JP3539474B2 - Polyamide resin for connector, resin composition and connector - Google Patents

Description

【００３６】
比較例１
原料のヘキサメチレンセバケートを同量のヘキサメチレンアジペートに変えた以外は実施例１と全く同様に重合、成形、特性評価を行った。結果を表１に示すが、ここで得られたポリアミド樹脂は特に吸水時の剛性が低い実用に耐えないものであった。
【００３７】
比較例２
生成するポリアミドの組成がヘキサメチレンテレフタルアミド単位２５モル％、ヘキサメチレンセバカミド単位５０モル％、およびカプロアミド単位２５モル％となるよう原料混合比を変えた以外は実施例１と全く同様に重合、成形、特性評価を行った。結果を表１に示すが、ここで得られたポリアミド樹脂も吸水時の剛性が低い実用に耐えないものであった。
【００３８】
比較例３
生成するポリアミドの組成がヘキサメチレンテレフタルアミド単位６５モル％、ヘキサメチレンアジパミド単位３０モル％、およびカプロアミド単位５モル％となるよう原料混合比を変えた以外は実施例１と全く同様に重合、成形、特性評価を行った。結果を表１に示すが、ここで得られたポリアミド樹脂は融点が高すぎ、溶融安定性が不十分で実用に耐えないものであった。
【００３９】
実施例２〜６
生成するポリアミド樹脂が表１に示す組成となるように原料の混合比を変えた以外は実施例１と全く同様の手順で重合、成形、特性評価を行った。結果は表１に示す通りであり、ここで得られたポリアミド樹脂も吸水時の剛性、寸法安定性にすぐれたものであった。
【００４０】
実施例７〜１１
先の実施例１〜５で得られたポリアミド樹脂と無水マレイン酸で変性したポリエチレンおよび／またはポリプロピレンを表２に示す配合比で２軸押出機を用いて溶融混練した後、順次射出成形、特性評価を行った。結果は表２にまとめた通り、いずれもすぐれた特性を有する組成物であった。
【００４１】
【表２】

【００４２】
【発明の効果】
本発明で得られるポリアミド樹脂および樹脂組成物は機械的特性、耐熱性、成形性、寸法安定性にすぐれ、かつ、高湿度雰囲気下で長時間使用しても剛性低下が小さく、耐久性にすぐれ、吸水による寸法変化が小さく、特に薄肉部分を有する自動車ハーネスコネクター成形品の製造に好適であり、得られたコネクター成形品は実用価値の高いものである。
【図面の簡単な説明】
【図１】実施例で作製したコネクター成形品の概略図であり、（Ａ）は平面図、（Ｂ）は正面図である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a polyamide resin composition having excellent mechanical properties, heat resistance, moisture resistance, and moldability, and particularly having excellent rigidity and dimensional stability when placed in a high humidity environment. More specifically, it maintains high toughness, which is a characteristic of polyamide resin, and has high heat resistance, high moisture resistance, and high dimensional stability with extremely small decrease in rigidity even after long-term exposure to high humidity environment. The present invention relates to a polyamide resin and a composition thereof, which are suitably used for a connector used mainly in an engine room of an automobile.
[0002]
[Prior art]
Polyamide resins typified by nylon 6 and nylon 66 have excellent properties as engineering plastics, and are widely used in various industrial fields such as automobiles, electricity and electronics.
[0003]
In recent years, automotive parts, especially harness connectors used in the engine room, have been used in harsh usage environments such as high temperatures and high humidity in the engine room, due to the high performance and high output of the engine performance. There is an increasing demand for materials that can maintain the binding and connection functions. In response to such advanced demands, especially for nylon 6 and nylon 66 resins that are used for general purposes, the connection function is impaired due to reduced water absorption, and the dimensional change is large and the dimensional stability is inferior, especially due to water absorption. There was a problem.
[0004]
Recently, as polyamide resins which can be used even in such severe use environments, JP-A-59-155426, JP-A-62-156130 and JP-A-3-201375 disclose terephthalic acid and / or terephthalic acid. Alternatively, a high melting point copolyamide resin containing isophthalic acid is disclosed. These polyamide resins have a high melting point and at the same time suppress the water absorption by the introduction of aromatic dicarboxylic acid units, and can exhibit high rigidity and dimensional stability even in a high humidity environment.On the other hand, due to their high melting points, melt molding methods Molding processability is significantly impaired, such as the intrusion of foreign substances presumed to be caused by gelation or carbonization of the polymer during the production of molded products, which is insufficient to produce practical molded products with good productivity. There was a problem that is.
[0005]
JP-A-61-283653 describes that the impact resistance is improved by adding a modified polyolefin to the above-mentioned high-melting point copolyamide resin. Although the impact resistance is certainly improved to some extent by this technique, the initial rigidity is low, and it has not been possible to suppress a decrease in rigidity especially after long-time use in a high-humidity use environment.
[0006]
[Problems to be solved by the invention]
As described above, according to the conventional technology, it is difficult to obtain a polyamide resin or a composition using the same, in which the decrease in rigidity under a high humidity atmosphere is small, and the heat resistance, toughness, and moldability are well balanced. there were.
[0007]
Therefore, the present invention has excellent mechanical properties, heat resistance, moldability, and dimensional stability, and has a small decrease in rigidity even when used for a long time in a high-humidity atmosphere. It is an object of the present invention to obtain a polyamide resin and a resin composition suitable for producing an automobile harness connector molded product having a small thickness, particularly a thin portion.
[0008]
[Means for Solving the Problems]
That is, the present invention
1. "(A) hexamethylene terephthalamide units 60 to 30 mol% and (b) 70 to 40 mol% of aliphatic polyamide units having 8 or more carbon atoms (amide group concentration) per amide group, A polyamide resin for a connector having characteristics in the following range.
(A) Melting point: 280 ° C. or more and less than 300 ° C. (b) A glass transition point at the time of saturated water absorption determined by viscoelasticity measurement of 25 ° C. or more, and at least one peak among a plurality of peak values of the loss elastic coefficient observed. Is above 80 ° C. "
2. "(A) 60 to 30 mol% of hexamethylene terephthalamide units, (b ') aliphatic polyamide units which have not less than 8 carbon atoms per amide group (amide group concentration) and are not defined in the following component (c) 65 to 35 mol% and (c) 5 to 35 mol% of at least one structural unit selected from undecaneamide units, dodecaneamide units and caproamide units, and the properties thereof are within the following ranges. Characteristic polyamide resin for connectors.
(A) Melting point: 280 ° C. or more and less than 300 ° C. (b) A glass transition point at the time of saturated water absorption determined by viscoelasticity measurement of 25 ° C. or more, and at least one peak among a plurality of peak values of the loss elastic coefficient observed. Is above 80 ° C. "
3. "The polyamide resin for a connector, wherein the aliphatic polyamide unit of the component (b) or (b ') is a hexamethylene sebacamide unit."
4. “A polyamide resin for a connector according to any one of the above, wherein the polyamide unit of the component (c) is a caproamide unit.”
5. "Any polyamide resin for a connector as described above, wherein the polyamide unit of the component (c) is a dodecaneamide unit."
6. "Any polyamide resin for a connector as described above, wherein the aliphatic polyamide unit of the component (b ') is a hexamethylene sebacamide unit, and the polyamide unit of the component (c) is a caproamide unit."
7. "Any polyamide resin for a connector as described above, wherein the aliphatic polyamide unit of the component (b ') is a hexamethylene sebacamide unit and the polyamide unit of the component (c) is a dodecaneamide unit."
8. "The polyamide resin for a connector according to any one of the above, wherein the connector is an automotive connector."
9. "(A) 60 to 30 mol% of (a) hexamethylene terephthalamide units and (b) 70 to 40 mol% of aliphatic polyamide units having 8 or more carbon atoms (amide group concentration) per amide group. Further, a polyamide resin composition for a connector comprising 99 to 80% by weight of a polyamide resin having the following properties, and 1 to 20% by weight of a modified polyolefin (B) modified with a carboxylic acid and / or a derivative thereof.
(A) Melting point: 280 ° C. or more and less than 300 ° C. (b) A glass transition point at the time of saturated water absorption determined by viscoelasticity measurement of 25 ° C. or more, and at least one peak among a plurality of peak values of the loss elastic coefficient observed. Is above 80 ° C. "
10. "(A) (a) 60 to 30 mol% of hexamethylene terephthalamide units, (b ') a fat which has not less than 8 carbon atoms (amide group concentration) per amide group and is not defined as the following component (c): 65 to 35 mol% of group III polyamide units and (c) 5 to 35 mol% of at least one structural unit selected from undecane amide units, dodecane amide units and caproamide units, and the properties thereof are within the following ranges: A polyamide resin composition for a connector comprising 99 to 80% by weight of a certain polyamide resin and (B) 1 to 20% by weight of a modified polyolefin modified with a carboxylic acid and / or a derivative thereof.
(A) Melting point: 280 ° C. or more and less than 300 ° C. (b) A glass transition point at the time of saturated water absorption determined by viscoelasticity measurement of 25 ° C. or more, and at least one peak among a plurality of peak values of the loss elastic coefficient observed. Is above 80 ° C. "
11. "Homopolymer of α-olefin wherein the modified polyolefin of the component (B) contains at least one selected from carboxylic acid groups, carboxylic acid anhydride groups, carboxylic acid ester groups, and carboxylic acid metal bases in the polymer molecular chain. Or a polyamide resin composition for a connector, which is a copolymer. "
12. "A polyamide resin composition for a connector according to any one of the above, wherein the connector is an automotive connector.",
13. "A connector obtained by injection molding any of the above polyamide resins."
14． "A connector obtained by injection molding any of the polyamide resin compositions.",
Is provided.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
In the present invention, as the first polyamide resin (A), a fat having (a) 60 to 30 mol% of hexamethylene terephthalamide units and (b) 8 or more carbon atoms (amide group concentration) per amide group is used. The second polyamide resin (A) is composed of (a) 60 to 30 mol% of hexamethylene terephthalamide units, and (b ') the number of carbon atoms per one amide group (amide). (Group concentration) is 8 or more and at least one structural unit selected from 65 to 35 mol% of an aliphatic polyamide unit not defined as the component (c) below and (c) an undecaneamide unit, a dodecaneamide unit and a caproamide unit. What consists of 5-35 mol% is used.
[0010]
The (a) hexamethylene terephthalamide unit constituting the polyamide resin of the component (A) is a unit synthesized from hexamethylene diamine and a derivative of terephthalic acid or an ester or acid halide thereof, and the component (c) is composed of 12 units. -Aminododecanoic acid, ω-laurolactam, 11-aminoundecanoic acid, ε-aminocaproic acid, units derived from raw materials such as ε-caprolactam. Specific examples of the raw material for providing an aliphatic polyamide unit having a carbon atom number (amide group concentration) of 8 or more per amide group of the component (b) or the component (b ′) include hexamethylene diammonium sebacate and hexamethylene diammonium sebacate. Examples include methylene diammonium decanoate, hexamethylene diammonium undecanoate, hexamethylene diammonium dodecanoate, 12-aminododecanoic acid, ω-laurolactam, 11-aminoundecanoic acid, and the like.
[0011]
When the polyamide component is a two-component system comprising the components (a) and (b), the components (a) and (b) are added in proportions of 60 to 30 mol% and 70 to 40 mol%, respectively, preferably 60 to 30 mol%. In the case of a ternary system comprising the components (a), (b ') and (c), it may be contained in the proportions of 45 mol% and 40 to 55 mol%, and (a), (b') and ( The copolymer which contains the component c) in a proportion of 60 to 30, 65 to 35 and 5 to 35 mol%, respectively, preferably in a proportion of 55 to 45, 45 to 50 and 5 to 10 mol%, respectively. Necessary in the invention.
[0012]
This is because a copolymerized polyamide obtained by polymerizing the above specific copolymerization component in a very limited copolymerization ratio and having a specific melting point, viscoelastic behavior, and viscoelastic behavior upon water absorption is used for an automotive connector. This is because, when used as such, there is little decrease in rigidity in a high humidity atmosphere, and preferable performances such as excellent balance of heat resistance, toughness, and moldability can be exhibited. In particular, it is important that a glass transition point of 25 ° C. or higher is maintained during water absorption, and a segment having a loss elastic modulus peak of 80 ° C. or higher is present.
[0013]
If the copolymerization amount of the component (a) is larger than the above range, the melting point of the produced polyamide resin becomes too high (for example, more than 300 ° C.), deterioration during melting becomes apparent, and the possibility of foreign matter mixing into molded articles increases. On the contrary, if the amount is less than the above range, the viscoelastic properties at the time of water absorption are unpreferably decreased. If the copolymerization amount of the component (b) or the component (b ') is larger than the above range, the melting point is lowered, and the required heat resistance cannot be maintained. It is not preferable because the water absorption increases and the rigidity at the time of water absorption decreases. In the case of a three-component system, if the copolymerization amount of the component (c) is larger than the above range, the melting point also decreases and the required heat resistance cannot be maintained, which is not preferable. This is not preferred because the fluidity of the resulting polyamide resin is reduced.
[0014]
Although the degree of polymerization of the polyamide resin of the present invention is not particularly limited, the relative viscosity measured at 25 ° C. in a 1% concentrated sulfuric acid solution is usually 1.5 in terms of mechanical properties and moldability. To 5.0, preferably 1.8 to 3.5, particularly preferably 2.0 to 2.8. In the polyamide resin of the present invention, a small amount of an amide component not defined in (a) to (c) can be contained as long as the effects of the present invention are not impaired.
[0015]
Although the method for producing the polyamide resin of the present invention is not particularly limited, ordinary pressure melt polymerization, for example, mixing of hexamethylene diammonium terephthalate (6T salt) with hexamethylene diammonium sebacate (610 salt) and ε-caprolactam The aqueous solution is heated and reacted under a steam pressure of 15 to 30 kg / cm ² , and then melt polymerization is carried out while releasing water in the system. Alternatively, the raw material aqueous solution is heated at 150 to 320 ° C. to temporarily form a prepolymer. And a method of solid-state polymerization at a temperature below the melting point or a method of increasing the degree of polymerization with a melt extruder. Among them, the pressure melt polymerization method is simple and suitable.
[0016]
The polyamide resin of the present invention may contain additives such as a viscosity modifier, a pigment, an anti-coloring agent, and a heat-resistant agent as long as the properties are not impaired.
[0017]
In the present invention, a modified polyolefin modified with a carboxylic acid and / or a derivative thereof (B), which is appropriately used as necessary, is blended as a composition for further improving properties. Such a component is a polyolefin containing, in its molecule, a functional group having an affinity for a polyamide resin, particularly a carboxylic acid group, a carboxylic acid anhydride group, a carboxylic acid ester group, or a carboxylic acid metal base. Α-olefin homopolymers or copolymers containing at least one member selected from the group consisting of:
[0018]
Specific examples of the α-olefin homopolymer or copolymer include homopolymers such as polyethylene, polypropylene, polybutene-1, polypentene-1, and polymethylpentene, ethylene, propylene, butene-1, pentene-1, 4-methylpentene. -1, α-olefins such as isobutylene, 1,4-hexadienedicyclopentadiene, 2,5-norbornadiene, 5-ethylidene norbornene, 5-ethyl-2,5-norbornadiene, 5- (1′-probenyl) -2 And polyolefins obtained by radical polymerization of at least one non-conjugated diene such as norbornene.
[0019]
The diene-based elastomer is an AB-type or ABA'-type block copolymer elastic material composed of a vinyl aromatic hydrocarbon and a conjugated diene, and the terminal blocks A and A 'are different even if they are the same. And an aromatic moiety may be a thermoplastic homopolymer or copolymer derived from a vinyl aromatic hydrocarbon which may be monocyclic or polycyclic.Examples of such a vinyl aromatic hydrocarbon include Styrene, α-methylstyrene, vinyltoluene, vinylxylene, ethylvinylxylene, vinylnaphthalene, and mixtures thereof. The intermediate polymer block B is made of a conjugated diene-based hydrocarbon, and examples thereof include 1,3-butadiene, 2,3-dimethylbutadiene, isoprene, 1,3-pentadiene, and a polymer derived from a mixture thereof. In the present invention, those obtained by subjecting the intermediate polymer block B of the block copolymer to a hydrogenation treatment are also included.
[0020]
Specific examples of the polyolefin copolymer include ethylene / propylene copolymer, ethylene / butene-1 copolymer, ethylene / propylene / dicyclopentadiene copolymer, ethylene / propylene / 5-ethylidene-2-norbornene copolymer, Examples include unhydrogenated or hydrogenated polybutadiene, unhydrogenated or hydrogenated styrene / isoprene / styrene triblock copolymer, and unhydrogenated or hydrogenated styrene / butadiene / styrene triblock copolymer.
[0021]
Examples of the functional group that modifies these polyolefins include a carboxylic acid group, a carboxylic acid anhydride group, a carboxylic acid ester group, a carboxylic acid metal base carboxylic acid imide group, and a carboxylic acid amide group. For example, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, methyl maleic acid, methyl fumaric acid, mesaconic acid, citraconic acid, glutaconic acid and metal salts of these carboxylic acids, hydrogen maleate Methyl, methyl hydrogen itaconate, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, hydroxyethyl acrylate, methyl methacrylate, 2-ethylhexyl methacrylate, hydroxyethyl methacrylate, methacryl Aminoethyl acid, Dimethyl inmate, dimethyl itaconate, maleic anhydride, itaconic anhydride, citraconic anhydride, endobicyclo- (2,2,1) -5-heptene-2,3-dicarboxylic acid, endobicyclo- (2,2, 1) -5-Heptene-2,3-dicarboxylic anhydride, maleimide, N-ethylmaleimide, N-butylmaleimide, N-phenylmaleimide, glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, glycidyl itaconate, citracone Glycidyl acid and the like.
[0022]
The method for introducing these functional group-containing components is not particularly limited, and a method such as copolymerization or graft introduction to an unmodified polyolefin using a radical initiator can be used. The amount of the functional group-containing component to be introduced is suitably in the range of 0.001 to 40 mol%, preferably 0.01 to 35 mol%, based on the whole modified polyolefin polymer.
[0023]
Specific examples of the modified polyolefin particularly useful in the present invention include maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, ethylene / acrylic acid copolymer, ethylene / methacrylic acid copolymer, and carboxylic acid moiety in these copolymers. A part or all of which is a salt with sodium, lithium, potassium, zinc, calcium, ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer, ethylene / methyl methacrylate copolymer, ethylene / Ethyl methacrylate copolymer, ethylene / ethyl acrylate-g-maleic anhydride copolymer ("g" represents a graft, the same applies hereinafter), ethylene / methyl methacrylate-g-maleic anhydride copolymer , Ethylene / ethyl acrylate-g-maleimide copolymer, ethylene / a Ethyl acrylate-g-N-phenylmaleimide copolymer and partially saponified products of these copolymers, ethylene / glycidyl methacrylate copolymer, ethylene / vinyl acetate / glycidyl methacrylate copolymer, ethylene / methyl methacrylate / glycidyl methacrylate Copolymer, ethylene / glycidyl acrylate copolymer, ethylene / vinyl acetate / glycidyl acrylate copolymer, ethylene / glycidyl ether copolymer, ethylene / propylene-g-maleic anhydride copolymer, ethylene / butene-1- g-maleic anhydride copolymer, ethylene / propylene / 1,4-hexadiene-g-maleic anhydride copolymer, ethylene / propylene / dicyclopentadiene-g-maleic anhydride copolymer, ethylene / propylene / 2 , -Norbornadiene-g-maleic anhydride copolymer, ethylene / propylene-g-N-phenylmaleimide copolymer, ethylene / butene-1-g-N-phenylmaleimide copolymer, hydrogenated styrene / butadiene / styrene- g-maleic anhydride copolymer, hydrogenated styrene / isoprene / styrene-g-maleic anhydride copolymer, ethylene / propylene-g-glycidyl methacrylate copolymer, ethylene / butene-1-g-glycidyl methacrylate Copolymer, ethylene / propylene / 1,4-hexadiene-g-glycidyl methacrylate copolymer, ethylene / propylene / dicyclopentadiene-g-glycidyl methacrylate copolymer, hydrogenated styrene / butadiene / styrene-g- A glycidyl methacrylate copolymer can be used.
[0024]
In the present invention, the blending amount of the modified polyolefin as the component (B) is in the range of 1 to 20% by weight, and the preferred range is 3 to 10% by weight.
[0025]
In the polyamide resin composition obtained herein, an antioxidant, a heat stabilizer such as copper iodide, potassium iodide, a lubricant, a crystal nucleating agent, an ultraviolet ray inhibitor, a coloring agent, Conventional additives such as flame retardants and small amounts of other polymers can be added.
[0026]
The method for producing the present composition is not particularly limited, and after the polyamide resin, modified polyolefin and other additives of the present invention are dry-blended using a ribbon blender, a Henschel mixer, a V blender, or the like, a Banbury mixer, a mixing roll, A method of melt-kneading using a twin-screw or twin-screw extruder, a kneader or the like may be used. Among them, a method of melt-kneading using a single-screw or twin-screw extruder having a sufficient kneading force is typical.
[0027]
The polyamide resin and the resin composition obtained by the present invention have excellent mechanical properties, heat resistance, moldability, and dimensional stability, and have a small decrease in rigidity even when used for a long time in a high humidity atmosphere, and have excellent durability. Since the dimensional change due to water absorption is small, it is particularly suitable for producing an automobile harness connector molded product having a thin portion, and the obtained connector molded product has a high practical value.
[0028]
【Example】
Hereinafter, the effects of the present invention will be further described with reference to examples, but the present invention is not limited to only these examples.
In addition, various characteristics described in the examples and comparative examples were measured by the following methods.
[0029]
Melting point: Using an RDC220 type differential operation calorimeter manufactured by Seiko Electronic Industry Co., Ltd., the temperature was once raised at a heating rate of 40 ° C./min, kept at an endothermic peak temperature plus 20 ° C. for 5 minutes, and then kept at 20 ° C./min. After the temperature was lowered to 100 ° C. at a rate of 20 minutes, the peak value measured at a rate of temperature rise of 20 ° C./min was taken as the melting point.
[0030]
Viscoelastic behavior: A polyamide resin sample is melt-pressed to form a sheet having a thickness of about 0.2 mm, and a 2 × 50 mm strip-shaped test piece is cut out therefrom, using Toyo Baldwin's Leo Vibron DDV-II-EA. At a frequency of 110 Hz and a heating rate of 2 ° C./min. The peak temperature of the loss elastic modulus corresponding to α-dispersion was defined as the glass transition point. In addition, the peak temperature of the highest temperature of the loss elastic modulus observed by splitting specifically at the time of water absorption is shown as a high temperature side peak at the time of water absorption.
[0031]
・ Tensile strength: ASTM D638
-Flexural modulus: According to ASTM D790, the flexural modulus at the time of absolute drying and at the time of atmospheric equilibrium water absorption was measured.
[0032]
-Practical water absorption characteristics: The connector shown in FIG. 1 having a maximum value of 55 mm, a height of 13 mm, a depth of 37 mm, and a thickness of 1 mm is molded by injection molding, and this is placed as shown in FIG. Was placed under the conditions of 30 ° C. and 95% RH for 100 hours, and the degree of deformation of the molded article was observed. The criteria are as follows.
：: No deformation △: Small deformation X: Large deformation [0033]
-Stability during melt retention: The above connector is set at the cylinder temperature of the injection molding machine plus the melting point of the polyamide resin plus 30 ° C, retained in the cylinder for 15 minutes, and then molded to obtain foreign matter in the molded product. The number was counted and used as an index of stability during melt retention. The criteria are as follows.
：: The number of foreign substances is 1 or less Δ: The number of foreign substances is 1 to 2 X: The number of foreign substances is 3 or more
Example 1
Hexamethylene diammonium terephthalate (6T salt), hexamethylene diammonium sebacate (610 salt) prepared to have 55 mol% of hexamethylene terephthalamide units, 45 mol% of hexamethylene sebacamide units, and 5 mol% of caproamide units. And a mixed aqueous solution of ε-caprolactam (solid raw material concentration: 60% by weight) was charged into a pressure polymerization vessel, the temperature was increased with stirring, the reaction was carried out at a steam pressure of 19 kg / cm 2 for 1.5 hours, and then gradually over about 2 hours. , And reacted under normal pressure nitrogen stream for about 30 minutes. At this time, the temperature in the final polymerization reactor was 315 ° C. After the completion of the reaction, the produced polymer was discharged from the discharge port at the bottom of the polymerization vessel, cooled in a cooling bath, and pelletized. The polyamide resin obtained here had a relative viscosity of 2.30, and the properties were as shown in Table 1. Various test pieces were obtained by injection molding of this polyamide resin, and the properties were measured. As shown in Table 1, the test pieces had excellent rigidity and dimensional stability even when absorbing water, and were used as connector materials. It was useful.
[0035]
[Table 1]

[0036]
Comparative Example 1
Polymerization, molding, and property evaluation were performed in exactly the same manner as in Example 1 except that the raw material hexamethylene sebacate was changed to the same amount of hexamethylene adipate. The results are shown in Table 1. The polyamide resin obtained here had a particularly low rigidity at the time of water absorption and was not suitable for practical use.
[0037]
Comparative Example 2
The polymerization was performed in exactly the same manner as in Example 1 except that the raw material mixing ratio was changed so that the composition of the resulting polyamide was 25 mol% of hexamethylene terephthalamide units, 50 mol% of hexamethylene sebacamide units, and 25 mol% of caproamide units. , Molding and characteristics evaluation. The results are shown in Table 1. The polyamide resin obtained here had a low rigidity at the time of absorbing water and was not practical.
[0038]
Comparative Example 3
Polymerization was carried out in exactly the same manner as in Example 1, except that the raw material mixing ratio was changed so that the composition of the resulting polyamide was 65 mol% of hexamethylene terephthalamide units, 30 mol% of hexamethylene adipamide units, and 5 mol% of caproamide units. , Molding and characteristics evaluation. The results are shown in Table 1. The polyamide resin obtained here had a melting point that was too high, had insufficient melt stability, and was not practical.
[0039]
Examples 2 to 6
Polymerization, molding, and property evaluation were performed in exactly the same procedures as in Example 1 except that the mixing ratio of the raw materials was changed so that the resulting polyamide resin had the composition shown in Table 1. The results are as shown in Table 1. The polyamide resin obtained here was also excellent in rigidity and dimensional stability when absorbing water.
[0040]
Examples 7 to 11
The polyamide resin obtained in Examples 1 to 5 and the polyethylene and / or polypropylene modified with maleic anhydride were melt-kneaded using a twin-screw extruder at the compounding ratio shown in Table 2, and then injection-molded sequentially. An evaluation was performed. The results, as summarized in Table 2, were all compositions having excellent properties.
[0041]
[Table 2]

[0042]
【The invention's effect】
The polyamide resin and the resin composition obtained by the present invention have excellent mechanical properties, heat resistance, moldability, and dimensional stability, and have a small decrease in rigidity even when used for a long time in a high humidity atmosphere, and have excellent durability. Since the dimensional change due to water absorption is small, it is particularly suitable for the production of an automobile harness connector molded product having a thin portion, and the obtained connector molded product is of high practical value.
[Brief description of the drawings]
FIG. 1 is a schematic view of a connector molded product produced in an example, (A) is a plan view, and (B) is a front view.

Claims (14)

(A) 60 to 30 mol% of hexamethylene terephthalamide unit and (b) 70 to 40 mol% of an aliphatic polyamide unit having 8 or more carbon atoms (amide group concentration) per amide group, and furthermore, its characteristics Is within the following range: a polyamide resin for a connector.
(A) Melting point: 280 ° C. or more and less than 300 ° C. (b) A glass transition point at the time of saturated water absorption determined by viscoelasticity measurement of 25 ° C. or more, and at least one peak among a plurality of peak values of the loss elastic coefficient observed. Is above 80 ° C (A) hexamethylene terephthalamide unit 60 to 30 mol%, (b ') aliphatic polyamide unit 65 having not less than 8 carbon atoms per one amide group (amide group concentration) and not defined in component (c) below And (c) 5 to 35 mol% of at least one structural unit selected from the group consisting of undecane amide units, dodecane amide units and caproamide units, and the properties thereof are within the following ranges. Characteristic polyamide resin for connectors.
(A) Melting point: 280 ° C. or more and less than 300 ° C. (b) A glass transition point at the time of saturated water absorption determined by viscoelasticity measurement of 25 ° C. or more, and at least one peak among a plurality of peak values of the loss elastic coefficient observed. Is above 80 ° C The polyamide resin for a connector according to claim 1 or 2, wherein the aliphatic polyamide unit of the component (b) or the component (b ') is a hexamethylene sebacamide unit. The polyamide resin for a connector according to claim 2, wherein the polyamide unit (c) is a caproamide unit. The polyamide resin for a connector according to claim 2, wherein the polyamide (c) is a dodecaneamide unit. The polyamide resin for a connector according to claim 4, wherein the aliphatic polyamide unit of the component (b ') is a hexamethylene sebacamide unit, and the polyamide unit of the component (c) is a caproamide unit. The polyamide resin for a connector according to claim 5, wherein the aliphatic polyamide unit of the component (b ') is a hexamethylene sebacamide unit, and the polyamide unit of the component (c) is a dodecaneamide unit. The polyamide resin for a connector according to any one of claims 1 to 7, wherein the connector is an automotive connector. (A) (a) hexamethylene terephthalamide units (60 to 30 mol%) and (b) 70 to 40 mol% of aliphatic polyamide units having 8 or more carbon atoms (amide group concentration) per amide group, Further, a polyamide resin composition for a connector comprising 99 to 80% by weight of a polyamide resin having the following characteristics, and 1 to 20% by weight of (B) a modified polyolefin modified with a carboxylic acid and / or a derivative thereof.
(A) Melting point: 280 ° C. or more and less than 300 ° C. (b) A glass transition point at the time of saturated water absorption determined by viscoelasticity measurement of 25 ° C. or more, and at least one peak among a plurality of peak values of the loss elastic coefficient observed. Is above 80 ° C. (A) (a) 60 to 30 mol% of hexamethylene terephthalamide units, (b ') an aliphatic group which has 8 or more carbon atoms (amide group concentration) per amide group and is not defined in the following component (c) It consists of 65 to 35 mol% of polyamide units and (c) 5 to 35 mol% of at least one structural unit selected from undecane amide units, dodecane amide units and caproamide units, and the properties thereof are in the following ranges. A polyamide resin composition for a connector comprising 99 to 80% by weight of a polyamide resin and (B) 1 to 20% by weight of a modified polyolefin modified with a carboxylic acid and / or a derivative thereof.
(A) Melting point: 280 ° C. or more and less than 300 ° C. (b) A glass transition point at the time of saturated water absorption determined by viscoelasticity measurement of 25 ° C. or more, and at least one peak among a plurality of peak values of the loss elastic coefficient observed. Is above 80 ° C. (B) the modified polyolefin of the component is a homopolymer of an α-olefin containing at least one selected from a carboxylic acid group, a carboxylic acid anhydride group, a carboxylic acid ester group, and a carboxylic acid metal base in a polymer molecular chain; The polyamide resin composition for a connector according to claim 9 or 10, which is a copolymer. The polyamide resin composition for a connector according to any one of claims 9 to 11, wherein the connector is a connector for an automobile. A connector obtained by injection-molding the polyamide resin according to claim 1. A connector obtained by injection-molding the polyamide resin composition according to claim 9.

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