JP2502670B2 - Resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a molding resin composition, and more particularly to a polyamide resin composition having improved dimensional stability.

(Prior Art) Polyamide resins have excellent mechanical, thermal and chemical properties and are widely used as molding materials. Among them, nylon 46 has a melting point of 295 ° C., which is remarkably higher than general polyamides such as 220 ° C. for nylon 6, 260 ° C. for nylon 66, 220 ° C. for polybutylene terephthalate, and 260 ° C. for polyethylene terephthalate. Further, the crystallization rate is high, and therefore it is most suitable as a soldering resistant molding material.
It also has a wide range of industrial applications, with little deterioration in rigidity under high temperature atmosphere and excellent chemical resistance.

In addition, the material in which nylon 46 is reinforced with glass fiber has more excellent mechanical properties and is used in more advanced mechanical parts.

In recent years, in particular, the surface mounting of electronic parts has made remarkable progress, and solder resistance has come to be noted as a particularly important property. Nylon 46 is the most excellent material as far as its solder resistance is concerned, and its wide application is expected from the electric and electronic fields.

Specific application examples include various connectors, slide switches, keyboard switches, toggle switches, SMD transformer inductors, DIP switches and the like.

However, in such electronic components, dimensional stability is extremely important, and although nylon 46 is extremely excellent in solder resistance, it is not always satisfactory in dimensional stability.

That is, the non-reinforced nylon 46 has a drawback that the molding shrinkage rate is large, and dimensional changes due to moisture absorption and sink marks occur. Further, the glass fiber reinforced nylon 46 has a drawback that the degree of warp deformation is large. Therefore, although nylon 46 is extremely excellent in solder resistance, it still has a problem in dimensional stability, and its use was greatly limited.

As an attempt to improve such dimensional stability of nylon 46, there is JP-A-61-188459, in which terephthalic acid and / or isophthalic acid and trimethylhexamethylenediamine and / or hexamethylene are used for nylon 46. It has been proposed to blend an amorphous aromatic polyamide consisting of a diamine. However, although this method improves the dimensional stability, it has a problem in that the heat resistance represented by the solder resistance is lowered.

(Problems to be Solved by the Invention) In view of such circumstances, an object of the present invention is to improve the dimensional stability of nylon 46 without impairing its solder resistance.

(Means for Solving the Problem) The inventors of the present invention have conducted extensive studies for this purpose, and as a result, by blending nylon 46 with a specific copolyamide, or by further blending an inorganic filler as necessary. The present invention was found by finding that the resin composition obtained by hardening satisfies the object of the present invention.

That is, the present invention comprises (A) nylon 46 30 to 95% by weight, (B) isophthalic acid 50 to 10% by mole, and terephthalic acid 0.
~ 40 mol% and hexamethylenediamine 45-5 mol% and general formula [I] (However, R ₁ and R ₂ may be the same or different and each represents hydrogen or an alkyl group having 1 to 3 carbon atoms.) From 5 to 45 mol% of the alicyclic diamine represented by It relates to a resin composition comprising 5 to 70% by weight of the obtained copolyamide and 0 to 50% by weight of the inorganic filler (C).

Nylon 46 used in the present invention includes polytetramethylene adipamide obtained from tetramethylene diamine and adipic acid and copolymerized polyamide having polytetramethylene adipamide unit as a main component. Further, another polyamide may be contained as a mixed component as long as the properties of nylon 46 are not impaired. The copolymerization component is not particularly limited, and a known amide-forming component can be used. As typical examples of the copolymerization component, amino acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid and para-aminomethylbenzoic acid, ε-caprolactam, ω
-Lactams such as lauryllactam, hexamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, metaxylylenediamine, Paraxylylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 1-amino-3-aminomethyl-3,5,5 trimethylcyclohexane, bis (3-methyl- Diamines such as 4-aminocyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane, bis (aminopropyl) piperazine and aminoethylpiperazine, and adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanenic acid, terephthalate Acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5 Dicarboxylic acids such as methyl isophthalic acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, diglycolic acid, etc. can be mentioned, and other polyamides used as a mixed component are composed of these components. Can be mentioned.

The method for producing nylon 46 used in the present invention is optional. For example, JP-A-56-149430, JP-A-56-149431
JP-A-58-83029 and JP-A-61-43631
The method disclosed in Japanese Patent Application Laid-Open No. 2002-242242, that is, a prepolymer having a small number of cyclic end groups is first produced under specific conditions, and then solid-state polymerization is performed in a steam atmosphere to prepare nylon 46 for a high year or 2-pyrrolidone. And a method of obtaining it by heating in a polar organic solvent such as N-methylpyrrolidone. Although the degree of polymerization of nylon 46 is not particularly limited, the relative viscosity at 30 ° C and 96% sulfuric acid at 1 g / dl is 2.0 to
Nylon 46 in the range of 6.0 is preferably used.

The alicyclic diamine, which is one of the diamine components of the copolyamide used in the present invention, is represented by the general formula [I].

(Here, R ₁ and R ₂ may be the same or different and each represents hydrogen or an alkyl group having 1 to 3 carbon atoms.) Preferred specific examples of these alicyclic diamines include bis- ( 4-aminocyclohexyl) methane, bis- (4
-Amino-3-methylcyclohexyl) methane, bis-
(4-aminocyclohexyl) propane, bis- (4-
Amino-3-methylcyclohexyl) propane.

The copolyamide used in the present invention is produced by a known method. For example, Japanese Examined Patent Publication No. 46-41024 discloses a method for producing a copolyamide comprising four components of terephthalic acid, isophthalic acid, hexamethylenediamine and bis- (4-aminocyclohexyl) methane. As a method for producing such a copolyamide, it is a general method to first react a diamine component and a dicarboxylic acid component in water to form a salt first, and then perform polycondensation while concentrating the salt. The salt solution is preferably first prepolymerized in a closed autoclave under reaction pressure in the range from 200 ° C. to 350 ° C. and then the reaction is carried out at atmospheric pressure or under reduced pressure until the pressure is released and polycondensation reaches equilibrium.

The copolyamide used in the present invention preferably has a glass transition temperature of 100 ° C. or higher in order not to impair the heat resistance of the resin composition. The glass transition temperature can be measured by a general differential thermal analyzer. In order to obtain good physical properties, the relative viscosity of the copolyamide (1% by weight of the copolyamide, measured at 20 ° C using m-cresol solution) is
It is preferably in the range of 1.2 to 1.8.

The blending ratio of nylon 46 and copolyamide in the resin composition of the present invention is 95: 5 to 30: 70% by weight, but the blending ratio is 95: 5 to 40:60 in order to maintain high heat resistance. It is preferably in the range of% by weight. If the compounding ratio of the copolyamide exceeds 70% by weight, the heat resistance will be greatly reduced.

Inorganic fillers optionally used in the present invention include glass fiber, carbon fiber, kaolin, mica, wollastonite, silica, calcium carbonate, talc, etc. used as a reinforcing material for polyamide. These fillers are preferably surface-treated with a silane coupling agent or the like for the purpose of further improving mechanical properties.

The blending ratio of the inorganic filler used as necessary in the present invention is preferably 0 to 50% by weight, and the blending ratio can be selected according to the purpose.

The resin composition of the present invention may further contain additives such as heat stabilizers, antioxidants, light stabilizers, lubricants, pigments, flame retardants and plasticizers.

Reference Example 1: Copolyamide (PA-1) 45 mol% isophthalic acid, 5 mol% terephthalic acid, 45 mol% hexamethylenediamine, bis- (4-amino-3)
Methylcyclohexyl) methane 5 mol% of raw material 10
Kg was charged into the reaction tank together with 5 kg of pure water, and the air in the reaction tank was purged with nitrogen several times. After raising the temperature to 90 ° C and stirring for about 5 hours, gradually increase the reaction temperature to 28 hours over 28 hours.
The temperature was raised to 0 ° C. under pressure (18 bar) with stirring in the tank.

Then, the pressure was released and the pressure was reduced to atmospheric pressure, and then polymerization was further performed at the same temperature for 6 hours. After completion of the reaction, the product was discharged from the reaction tank and cut to obtain pellets. The relative viscosity of the obtained pellets (the same measurement method as above) was 1.50. This copolymerized polyamide is designated as PA-1.

Reference Example 2: Copolyamide (PA-2) Isophthalic acid 40 mol%, terephthalic acid 10 mol%, hexamethylenediamine 40 mol%, bis- (4-aminocyclohexyl) methane 10 mol% and 1w based on the total amount.
Benzoic acid was added as a relative viscosity modifier so that t% was obtained, and a copolyamide was obtained by the same method as in Reference Example 1. The relative viscosity of this copolyamide was 1.42.
This copolymerized polyamide is designated as PA-2.

(Examples) Examples 1 to 4 and Comparative Examples 1 and 2 Nylon 46 ("STANYL" manufactured by DSM, Netherlands, relative viscosity 3.2 at 25 ° C concentration 1 g / dl in 96% sulfuric acid) and copolyamide PA-1 After mixing at the ratio of (Reference Example 1) and Table 1, temperature
It was dried at 100 ° C. under a reduced pressure of 1 torr for 16 hours. These mixtures were melt mixed in a twin-screw extruder. The temperature conditions of the cylinder were 250 ° C in the hopper, 300 ° C in the center and 310 ° C in the tip.

In addition, as shown in Table 2, glass chopped strands having a diameter of 13 μm were added from the second feeding section of the twin-screw extruder to reinforce the glass fibers. In each case, good cutting was possible and pellets were obtained. Temperature of the resulting pellets
Various test pieces were obtained by drying for 16 hours under a reduced pressure of 1 Torr at 100 ° C and molding at a cylinder temperature of 300 ° C and a mold temperature of 80 ° C using an ordinary injection molding machine.

For the purpose of comparison with the examples of the present invention, Table 1 and Table 2 show the physical properties of the nylon 46 obtained alone and the glass fiber reinforced product thereof.

In the resin composition of the present invention, the melting point, the bending strength, the bending elastic modulus, and the solder resistance are almost the same as those of nylon 46 alone. On the other hand, the dimensional change and physical property change due to the water absorption treatment are remarkably reduced in the resin composition of the present invention.

Examples 5 to 7 In the case of Examples 1 and 2 after mixing nylon 46 (“STANYL” manufactured by DSM Co., Netherlands, relative viscosity 4.0) and copolymerized polyamide PA-2 (Reference Example 2) in the ratio shown in Table 3. A test piece was obtained in the same manner as. Both pelletization and injection molding were successfully performed.

(Effects of the Invention) The resin composition of the present invention has almost the same performance in melting point, flexural strength, flexural modulus, and solder resistance as nylon 46 alone, and has no dimensional change and physical property change due to water absorption treatment. Remarkably less.

Continuation of the front page (56) Reference JP 61-188459 (JP, A) JP 62-164762 (JP, A) JP 58-38751 (JP, A) JP 62-156161 (JP , A)

Claims (1)

(57) [Claims] 1. (A) Nylon 46 30 to 95% by weight, (B)
Isophthalic acid 50 to 10 mol% and terephthalic acid 0 to 40 mol%
And hexamethylenediamine 45 to 5 mol% and the general formula [I] (However, R ₁ and R ₂ may be the same or different and each represents hydrogen or an alkyl group having 1 to 3 carbon atoms.) From 5 to 45 mol% of the alicyclic diamine represented by A resin composition comprising the copolymerized polyamide obtained in an amount of 5 to 70% by weight and the inorganic filler (C) in an amount of 0 to 50% by weight.