JP3155619B2 - Polyamide resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can stably provide a resin molded product having excellent mechanical properties, particularly excellent strength, rigidity and dimensional stability when absorbing water, and excellent surface appearance and weather resistance. The present invention relates to a crystalline polyamide resin composition useful as a structural material for use. The exterior structural material is a mechanical component or a structural component that requires a molded product surface workability (for example, textured workability, high surface glossiness, etc.) and requires relatively large strength and rigidity. For example, desk legs, chair legs,
Furniture supplies such as seats, cabins, wagon parts, etc., OA equipment field supplies such as notebook PC housings, door mirror stays, wheel rims, wheel caps, wipers, motor fans, seat lock parts, gears, lamp parts, etc. Electrical parts such as leeks, gears, hot air blower housings, and other field supplies, bicycle parts such as wheel rims, wheel spokes, saddles, saddle posts, handles, stands, cargo beds, valve housings, nails, screws, bolts, bolts and nuts And so on.

[0002]

2. Description of the Related Art Polyamide resins have excellent mechanical properties such as tensile strength and bending strength and elastic modulus, and have good heat resistance and chemical resistance. Therefore, they are used in many fields, especially for precision machine parts and structural materials. Have been.

[0003] However, when the polyamide is an aliphatic polyamide (for example, nylon 66, nylon 6, nylon 46), its use has been limited due to a decrease in strength and rigidity due to water absorption and a remarkable dimensional change. .

In order to solve this problem, studies have been made to use a polyamide containing an aromatic component (nylon 6I, nylon 6I / 6T copolymer, nylon 66 / 6T copolymer, etc.) to increase rigidity and suppress water absorption. (For example, Japanese Patent Publication 3-56576, Japanese Patent Publication 3-7721)
6 etc.). Of the polyamides containing these aromatic components, crystalline polyamides have a melting point that is too high and can be melt-molded only in an extremely limited temperature range and residence time, and those having a high glass transition point are sufficiently crystallized. In addition, a high-temperature mold equipped with an oil temperature controller and the like was required. Amorphous polyamides also have problems such as poor fluidity during molding, long molding time cycles, poor productivity, and poor chemical resistance, and are hardly practically used. Further, the above-mentioned aromatic polyamide has a defect that mold transferability is poor due to a high solidification rate, and uneven surface gloss is generated in, for example, surface embossing, and the surface appearance is extremely poor.

[0005] Structural materials, which mainly require appearance, also require light resistance (weather). JP-A-4-149234 discloses a 66 / 6T / 6I-based polyamide resin, which has low water absorption, dimensional stability,
Although it is a resin having excellent surface appearance, it is not a resin having sufficient (light) weather resistance and is unsuitable as a structural material requiring appearance.

As a method for improving the light resistance (weather) of polyamide, a method of adding a compound of carbon black, copper, manganese, a phosphorus compound, a benzophenone compound, a hindered amine compound or the like to a polyamide is known. Of these, copper compounds that are effective not only in light resistance (weather) but also in preventing thermal oxidative deterioration are often used, and their properties improve with the addition amount of the copper compound. However, the polyamide to which the copper compound is added has a problem of yellowing over time, which causes discoloration of the appearance color of a molded product. Therefore, the amount of the polyamide is limited and sufficient light resistance (weather) cannot be obtained. There was a problem. That is, strength rigidity at the time of water absorption, dimensional stability,
There has been no material having excellent properties in both surface appearance and sufficient light resistance (weather).

[0007]

SUMMARY OF THE INVENTION In view of the above circumstances, it is an object of the present invention to provide mechanical properties, particularly strength and rigidity when absorbing water.
An object of the present invention is to provide a molding material having excellent dimensional stability, surface appearance, weather (light) resistance, and the like.

[0008]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a specific aromatic component is copolymerized with nylon 66 at a specific ratio to form a specific carboxyl group. By obtaining a polyamide having a terminal group ratio and blending it with a mixture of a specific copper compound and an iodine compound and / or a manganese compound, the weather resistance is greatly improved without causing discoloration of the surface of the molded product. It has been found that a material excellent in strength, rigidity, dimensional stability, surface appearance and the like at the time of water absorption can be stably obtained.

That is, the present invention relates to (1) (a) hexamethylene adipamide (66) units obtained from adipic acid and hexamethylene diamine, in an amount of 30 to 95 units;
% By weight, (b) hexamethylene terephthalamide (6T) obtained from terephthalic acid and hexamethylene diamine
A polyamide comprising 0 to 40% by weight of units, (c) 5 to 30% by weight of hexamethylene isophthalamide (61) units obtained from isophthalic acid and hexamethylene diamine, and having a terminal group ratio of carboxyl groups of 65% or more On the other hand, a polyamide resin composition containing a mixture of a copper compound and an iodine compound and / or a manganese compound in a ratio satisfying the following formulas (1) to (3).

(1) 0.5 ppm ≦ copper ≦ 150 ppm (2) 20 ≦ iodine / copper ≦ 30 (molar ratio) (3) 0.5 ppm ≦ manganese ≦ 60 ppm (2) Polyamide resin composition 30 described in (1) It is a polyamide resin composition consisting of up to 95% by weight and 5 to 70% by weight of an inorganic filler.

The polyamide resin composition described in the above (1) is useful as a structural material for exterior, and the polyamide resin composition described in the above (2) is also useful as a structural material for exterior. Hereinafter, the present invention will be described in detail.

The crystalline polyamide of the present invention comprises (a) 30 to 95% by weight of 66 units, (b) 0 to 40% by weight of 6T units,
(c) Consists of 5-30% by weight 6I units. here,
If the 66 unit is less than 30% by weight, the glass transition point becomes too high, and furthermore, the crystallization is slow, so that the appearance is deteriorated due to the decrease in fluidity and the productivity is deteriorated due to the prolonged molding cycle. If 66 units are higher than 95% by weight,
The melting point and the solidification point are high, and the resin is easily solidified in the mold at the time of molding. For example, in a molded product reinforced with inorganic fibers, the inorganic fibers are raised on the surface of the molded product, or the transferability is poor in a molded product having a grain surface. Lose practical value,
Further, the rigidity is significantly reduced due to water absorption, and the dimensional stability is deteriorated. A more preferred composition ratio of 66 units is 50.
~ 80% by weight.

When the 6T unit is higher than 40% by weight, the melting point,
The solidification point becomes too high and molding can be performed only in a very limited range of molding conditions, or the resin is easily solidified and the appearance of the molded product deteriorates, and the practical value is lost. The amount of 6T units is preferably 5-37% by weight.

If the 6I unit is less than 5% by weight, the melting point and the solidification point are too high, and the appearance of the molded article is deteriorated, and the practical value is lost. If the 6I unit is higher than 30% by weight, the glass transition point becomes too high and crystallization is slowed down.
As described above, the appearance and productivity are deteriorated. In addition, the crystallinity sharply decreases, and the rigidity and the chemical resistance under heat deteriorate.

The relative viscosity of these three-component crystalline polyamides is 1.7 to 4.5 (1.0 g / d in 95.5% sulfuric acid).
1, measured at 25 ° C.). Preferably a relative viscosity of 1.8
~ 4.3. If the relative viscosity is lower than 1.7, the obtained molded article has low mechanical properties, particularly low tensile and bending properties, and becomes brittle, so that a molded article having excellent rigidity, which is one of the objects of the present invention, can be obtained. Absent. If the relative viscosity is higher than 4.3, the fluidity at the time of molding is poor, and no matter how the composition is controlled to the above-mentioned composition ratio, a molded product having good appearance can no longer be obtained at the time of molding.

The material of the present invention may be exposed to sunlight or fluorescent light depending on the application, and is required to have sufficient light resistance (weather). Therefore, a material having an extremely high level of light resistance (weather) is required as compared with a conventional polyamide material, and the present inventors have conducted a thorough study in consideration of this point. As a result, a mixture of a copper compound and an iodine compound was found. And / or a manganese compound has the following formula (1) with respect to polyamide having a terminal group ratio of carboxyl groups of 65% or more.
It has been found that, when the composition is satisfied so as to satisfy (3), a material having extremely high light resistance (weather) can be obtained without causing discoloration of the appearance of the molded article.

(1) 0.5 ppm ≤ copper ≤ 150 ppm (2) 20 ≤ iodine / copper ≤ 30 (molar ratio) (3) 0.5 ppm ≤ manganese ≤ 60 ppm [COO
H] / ([COOH] + [NH ₂ ])} × 100 (%)
Is the value calculated by If the compounding amount is larger than the numerical values shown in (1) to (3), yellow-green discoloration of the surface of the resin molded product is conspicuous, and especially when the resin is colored with a coloring agent, the color tone changes over time, and the commercial value Disappears. Conversely, if the amount is small, sufficient light resistance (weather) cannot be obtained. The preferred range is (1) '0.7 ppm ≤ copper ≤ 100 ppm (2) '22 ≤ iodine / copper ≤ 28 (molar ratio) (3)' 0.7 ppm ≤ manganese ≤ 55 ppm. In the present invention, a mixture of a copper compound and an iodine compound and a manganese compound are preferably used together, but a mixture of a copper compound and an iodine compound alone or a manganese compound alone can also be used. When the carboxyl group ratio is less than 65%, yellow-green discoloration on the surface of the resin molded product is conspicuous. The manganese compound is preferably added when light resistance (weather) is required. There is no particular problem even if manganese is added in excess of 60 ppm, but it is not necessary to add manganese in excess of 60 ppm because sufficient weather resistance can be obtained by combination with a copper compound and an iodine compound.

Examples of the copper compound include copper chloride, copper bromide, copper iodide, copper phosphate, copper ammonium complex, copper stearate, copper montanate, copper adipate, copper isophthalate, copper terephthalate, and benzoate. Examples of iodine compounds such as copper acid, copper pyrophosphate, copper acetate, and ammonia copper include potassium iodide, magnesium iodide, and ammonium iodide, and manganese compounds include manganese lactate and manganese pyrophosphate. These compounds may be added during the polymerization of the polyamide, or may be melt-kneaded using an ordinary single-screw or twin-screw extruder.

The method for polymerizing the crystalline polyamide of the present invention is not particularly limited, and includes melt polymerization, solution polymerization, interfacial polymerization, bulk polymerization,
Solid phase polymerization and a method combining these can be used, but generally, melt polymerization or a combination of melt polymerization and solid phase polymerization is suitable.

The inorganic filler referred to in the present invention includes glass fiber, carbon fiber, talc, kaolin, mica, wollastonite, calcium carbonate, magnesium carbonate, potassium titanate, etc., in an amount of 5 to 70 wt%, Preferably it is 10-65 wt%. If the amount of the inorganic filler is more than 70% by weight, the gloss of the surface of the molded product is reduced, and if the amount is less than 5% by weight, a foreign substance effect is caused, and the physical properties are reduced. Among them, glass fiber and carbon fiber are preferable. The method of blending the inorganic filler may be a method of melt-mixing using a conventional single-screw or twin-screw extruder.

A heat stabilizer, an antioxidant, a flame retardant, a lubricant, a release agent, a nucleating agent, a pigment, a dye, and the like can be added as long as the object of the present invention is not impaired. May be blended with other polyamide resins and other resins.

[0022]

The present invention will be described in more detail with reference to the following examples. The scope of the present invention is not limited by the examples.

The evaluation in the examples and comparative examples was performed by the following methods.

Relative viscosity: The polymer was dissolved in 95.5 ± 0.03% sulfuric acid at a concentration of 1.0 g / dl,
It was measured with an Ostwald viscosity tube.

Amino end group: The polymer was dissolved in a 90% aqueous phenol solution and subjected to potentiometric titration with 1 / 40N hydrochloric acid. (40 ° C.) Carboxyl end group: The polymer was dissolved in benzyl alcohol and titrated with a 1/10 N KOH ethylene glycol solution. Phenolphthalein was used as an indicator. (170 ° C.) Tensile properties: Performed according to ASTM D638.

Bending characteristics: Performed according to ASTM D790.

Appearance: The non-reinforced resin was injection-molded using a grain-finished mold, and the uniformity of grain transfer on the surface of the obtained molded article was visually judged. The GF-reinforced product was injection molded using a flat mold having a smooth surface, and the presence or absence of GF floating on the surface of the obtained molded product was visually determined.

Light resistance (weather) resistance: A test piece was put into a sunshine weatherometer (63 ° C., a shower was sprayed for 18 minutes in 2 hours; the light source was a xenon lamp), and the time until surface cracks were generated was examined. Was.

Example 1 Equimolar salt of adipic acid and hexamethylenediamine 1.2
5 kg, equimolar salt of terephthalic acid and hexamethylenediamine 0.75 kg, equimolar salt of isophthalic acid and hexamethylenediamine 0.50 kg, adipic acid and copper acetate in excess of 2 mol% based on the total acidity as copper components 15pp
m, 375 ppm of potassium iodide as an iodine component,
10 ppm of manganese lactate was added as a manganese component, and 2.5 kg of pure water was charged into an autoclave having an internal volume of 5 L. After sufficiently replacing with nitrogen, the temperature was raised from room temperature to 220 ° C. over about 1 hour with stirring. . Pressure 18
The temperature was raised to 260 ° C. over about 2 hours while removing water from the reaction system while maintaining the kg / cm ² to complete the reaction. After the reaction, the valve was closed and cooled to room temperature over about 8 hours to obtain about 2 kg of a polymer having a relative viscosity of 1.38. After pulverizing the obtained polymer, it was put into an evaporator having an internal volume of 10 L, and subjected to solid-state polymerization at 200 ° C. for 10 hours under a nitrogen stream. A relative viscosity of 2.35 was obtained by solid phase polymerization.

Example 2 Equimolar salt of adipic acid and hexamethylenediamine 2.0
A method similar to that of Example 1 except that 0 kg, an equimolar salt of isophthalic acid and hexamethylenediamine 0.50 kg, an adipic acid excess of 2 mol% with respect to the total acid content, and 2.5 kg of pure water were used as starting materials. The polymer was made with. The relative viscosity of the obtained polymer was 2.41. Example 3 Equimolar salt of adipic acid and hexamethylenediamine 1.6
25 kg, equimolar salt of terephthalic acid and hexamethylenediamine 0.375 kg, equimolar salt of isophthalic acid and hexamethylenediamine 0.50 kg, 2 parts for total acid content
A polymer was prepared in the same manner as in Example 1 except that a molar% excess of adipic acid and 2.5 kg of pure water were used as starting materials. The relative viscosity of the obtained polymer was 2.30.

Example 4 The same 66, 6T, 6I composition as in Example 1 was prepared by adding 35 ppm of copper acetate as a copper component, 875 ppm of potassium iodide as an iodine component, and 1 component of manganese lactate as a manganese component.
0 ppm was added, and a polymer was prepared in the same manner.
The relative viscosity of the obtained polymer was 2.35.

Example 5 The same 66 and 6I compositions as in Example 2 were used except that copper acetate was used as a copper component at 3 ppm and potassium iodide was used as an iodine component at 75 p.
pm, manganese lactate was added as a manganese component at 10 ppm, and a polymer was prepared in the same manner. The relative viscosity of the obtained polymer was 2.41.

Example 6 The polymer obtained in Example 5 and glass fiber (03JA416 manufactured by Asahi Fiber Glass Co., Ltd.) were mixed with a twin screw extruder (Wern).
and melt-kneading under the following conditions using ZSK25 manufactured by ER Co., Ltd. Set the cylinder temperature of the twin screw extruder to 280 ° C,
The polymer was charged from the hopper with a screw rotation of 100 rpm. Glass fibers were fed by side feed from Zone 4 such that the glass fiber content of the resin composition became 33 wt%. The polymer charging section and the glass fiber charging section were sufficiently purged with N ₂ . Vent vacuum was applied from Zone 6 (650 mmHg). Discharge amount of 9.4 kg / hr,
The resin temperature was 305 ° C.

The pellet thus obtained was heated at 80 ° C. under N ₂
Dry underneath for 24 hours.

Example 7 Glass fibers were blended with a polymer obtained in the same manner as in Example 6, except that the polymer was obtained in the same manner as in Example 1 (copper acetate was added so as to be 3 ppm as a copper component).

Comparative Example 1 Equimolar salt of adipic acid and hexamethylenediamine 2.5
0 kg, 3 ppm of copper acetate as a copper component, 75 ppm of potassium iodide as an iodine component, 10 ppm of manganese lactate as a manganese component, and a method similar to that of Example 1 except that 2.5 kg of pure water was used as a starting material. A polymer was made. The relative viscosity of the obtained polymer was 2.62.

Comparative Example 2 Equimolar salt of adipic acid and hexamethylenediamine 1.3
7 kg, 1.13 kg of equimolar salts of terephthalic acid and hexamethylenediamine, 3 ppm of adipic acid and copper acetate in excess of 2 mol% with respect to the total acid content as a copper component, 75 ppm of potassium iodide as an iodine component, and manganese lactate in an amount of 75 ppm. Add 10ppm as manganese component, pure water 2.5kg
Was prepared in the same manner as in Example 1 except that was used as a starting material. The relative viscosity of the obtained polymer is 2.30.
Met.

Comparative Example 3 Equimolar Salt of Adipic Acid and Hexamethylenediamine 1.2
5 kg, 1.25 kg of equimolar salt of isophthalic acid and hexamethylenediamine, 3 ppm of copper acetate as a copper component, 75 ppm of potassium iodide as an iodine component, 10 ppm of manganese lactate as a manganese component, and 2.5 kg of pure water A polymer was prepared in the same manner as in Example 1 except that the starting material was used. The relative viscosity of the obtained polymer was 2.50.

Comparative Example 4 A polymer was prepared in the same manner as in Example 1 with the same composition of 66, 6T and 6I as in Example 4 without adding an excess of 2 mol% of adipic acid. The relative viscosity of the obtained polymer is 2.
It was 40.

Comparative Example 5 A polymer was prepared in the same manner as in Example 1 with the same composition of 66, 6T and 6I, without adding copper acetate, potassium iodide and manganese lactate. The relative viscosity of the obtained polymer is 2.3.
It was 5.

COMPARATIVE EXAMPLE 6 The same 66, 6T, 6I composition as in Example 1 was used, and 160 ppm of copper acetate as a copper component, 4000 ppm of potassium iodide as an iodine component, and 10 ppm of manganese lactate as a manganese component were added. A% excess of adipic acid was added, and a polymer was prepared in the same manner as in Example 1.
The relative viscosity of the obtained polymer was 2.50.

Comparative Example 7 Equimolar salt of adipic acid and hexamethylenediamine 0.6
25 kg, 1.125 kg of equimolar salt of terephthalic acid and hexamethylenediamine, 0.50 kg of equimolar salt of isophthalic acid and hexamethylenediamine, 2
3 pp with a molar% excess of adipic acid and copper acetate as copper components
m, 75 ppm potassium iodide as an iodine component, 10 ppm manganese lactate as a manganese component,
A polymer was prepared in the same manner as in Example 1 except that 2.5 kg of pure water was used as a starting material. The relative viscosity of the obtained polymer was 2.30.

Comparative Example 8 The amount of glass fiber added to the polymer obtained in Example 5 was 7
Extruded to 2%. However, the extrudability was poor and the pellets could not be sampled.

Comparative Example 9 The amount of glass fiber added to the polymer obtained in Example 5 was 3
% In the same manner as in Example 6.

Comparative Example 10 The amount of glass fiber added to the polymer obtained in Comparative Example 5 was 5
0% was blended in the same manner as in Example 6.

A test piece was prepared from the obtained polymer using an injection molding machine (PS40E manufactured by Nissei Plastics Industry Co., Ltd.). The molding was performed at a cylinder temperature of 290 ° C. and a mold temperature of 80 ° C., with a cycle of injection for 10 seconds and cooling for 20 seconds.

Table 1 shows the results.

[0048]

[Table 1]

[0049]

According to the composition of the present invention, mechanical properties, in particular, rigidity when absorbing water, dimensional stability, surface appearance, and light resistance (weather) are obtained.
A molded article having excellent properties and the like can be obtained.

Claims (2)

(57) [Claims] 1. A. First Embodiment (a) hexamethylene adipamide (6) obtained from adipic acid and hexamethylene diamine
6) 30 to 95% by weight of units; (b) 0 to 40% by weight of hexamethylene terephthalamide (6T) units obtained from terephthalic acid and hexamethylene diamine; (c) hexamethylene isophthale obtained from isophthalic acid and hexamethylene diamine An amide (6I) unit composed of 5 to 30% by weight and a terminal group ratio of carboxyl groups of 65%
For the polyamide described above, B.I. A polyamide resin composition containing a mixture of a copper compound and an iodine compound and / or a manganese compound in a ratio satisfying the following formulas (1) to (3). (1) 0.5 ppm ≦ copper ≦ 150 ppm (2) 20 ≦ iodine / copper ≦ 30 (molar ratio) (3) 0.5 ppm ≦ manganese ≦ 60 ppm 2. The polyamide resin composition 3 according to claim 1,
A polyamide resin composition comprising 0 to 95 wt% and an inorganic filler of 5 to 70 wt%.