JPH07247422A - Polyamide-based resin composition - Google Patents

Abstract

PURPOSE:To obtain a composition capable of readily carrying out the melt molding in mixing two or more different kinds of polyamides. CONSTITUTION:This polyamide-based resin composition is obtained by mixing two or more kinds of polyamides and has the difference in end group concentration (Y) of polyamides after the mixing and the concentration (X) of phosphorus atoms of the polyamides after the mixing satisfying the following formula: Y>=0.44X {Y denotes ¦[concentration of terminal amino groups]-[concentration of terminal carboxyl groups] ¦X10<-6> (equiv./g); X denotes the concentration of phosphorus atoms (ppm)}.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamide composition composed of two or more kinds of polyamides, and to a composition which is easily melt-molded when mixing two or more kinds of polyamides of different kinds. Is.

[0002]

2. Description of the Related Art When a thermoplastic resin is molded by extrusion molding, an injection molding machine or the like, one of the important molding conditions is the melt viscosity of a raw material resin used for molding. On the other hand, for the purpose of improving the properties of various thermoplastic resins, mixing two or more kinds of resins having different properties is a commonly adopted method. At this time, when two or more kinds of resins having reactive groups at the terminals such as polyamide are melt-mixed, the melt viscosity of the resin composition after mixing significantly increases the arithmetic mean value or logarithmic mean value of the melt viscosity of the raw resin before mixing. There may be observed a phenomenon exceeding the above. Furthermore, when a large amount of phosphorus compound is present in the resin during mixing, the same phenomenon may be observed. When a resin composition containing two or more kinds of polyamides is melted by heating and subjected to molding, when the melt viscosity of the resin composition reaches a value that greatly exceeds the melt viscosity of a single starting polyamide, the moldability decreases. The problem of doing.

When the viscosity of the molten resin is greatly increased in this way, a molding machine requires remarkably large extrusion power and injection pressure, and the extrusion amount and the injection amount are likely to be unstable, resulting in the thickness accuracy and dimensional accuracy of the molded product. Is difficult to secure and the transferability is also reduced. Further, since a large pressure resistance is required for the flow path pipe of the molten resin, the die, and the injection nozzle, there arises a problem that equipment needs to be improved or a new installation needs to be made.

[0004]

The object of the present invention is to overcome the above-mentioned problems of the prior art and to suppress an increase in melt viscosity when melt mixing two or more polyamides, and to provide excellent moldability. Another object is to provide a polyamide composition.

[0005]

The present invention relates to a polyamide composition comprising a mixture of two or more polyamides, wherein the difference Y in terminal concentration of the polyamide after mixing and the phosphorus atom concentration of the polyamide after mixing. The present invention relates to a polyamide composition, wherein X satisfies the following formula (1).

[0006]

(2) Y ≧ 0.44X (1) (where Y is | [terminal amino group concentration] − [terminal carboxyl group concentration] | × 10 ⁻⁶ (equivalent / g), X is phosphorus atom concentration Hereinafter, the present invention will be described in detail.

It is known that the polymer substance is a mixture of a large number of polymer chains having different lengths, and the polyamide is a mixture of a large number of polymer chains having a different length, as in this example. In the case of polyamide, one polymer chain has two end groups unless it is branched, but the end groups of all polymer chains are not the same, and (a) both end groups are amino groups. , (B) with both terminal groups being carboxyl groups,
(C) One having an amino group and the other having a carboxyl group,
Is a mixture of polymer chains having three types of terminal groups. Which of these (a) to (c) is the terminal group depends on the type of raw material, the proportion of the raw material, the production method, the modifier, the end capping agent and the like in the production of polyamide.

In addition, a phosphorus compound is usually added for the purpose of accelerating the reaction or preventing oxidation during the production of polyamide. Depending on the type of polyamide, the phosphorus compound may be removed in the water treatment process in the manufacturing process, but the phosphorus compound added in the manufacturing process remains as it was at the time of addition, or as a phosphorus compound that changed during manufacturing. Some are doing it.

According to the experiments conducted by the present inventor, the melt viscosity greatly increases when melt-molding a polyamide composition comprising two or more types because the difference in the terminal group concentration of individual polyamides and the inclusion of phosphorus compounds. It was found that the cause was related to the quantity. Due to the relationship between the difference in the terminal group concentration of the polyamide and the content of the phosphorus compound, the details of the reason why the melt viscosity greatly increases during melting are unknown, but the amino terminal group and the carboxyl terminal of the polyamide composition mixed during melting are unknown. Base,
The interpolymer reaction is promoted by the phosphorus compound, the pressure at the time of melting, and the heat, the reaction occurs between the terminal groups of the polymer chains of polyamide, and long polymer chains are generated, so that the melt viscosity is increased. Presumed.

According to the experiments conducted by the present inventor, in order to effectively achieve the object of the present invention, when two or more polyamides are melt-mixed, the terminal amino group concentration of the polyamide-based composition formed by mixing them is When the absolute value of the difference from the terminal carboxyl group concentration (× 10 ⁻⁶ (equivalent / g)) is Y and the phosphorus atom concentration (ppm) contained is X, Y ≧ 0.44
It turns out that X needs to be met.

Here, the terminal amino group concentration and the terminal carboxyl group concentration of the polyamide composition can be confirmed by an acid-base titration method generally used in the technical field of polyamide. Regarding the phosphorus atom concentration, after wet ashing 1 g of the polyamide composition after mixing, 2,4 dinitrophenol pH indicator was added dropwise, ammonia water was added until a slight yellow color was added, and 10 ml of vanadomolybdic acid was further added. After that, water is added and the weight is weighed to 25 ml, and the mixture is allowed to stand for 20 minutes or more and then analyzed by an absorptiometer.

X and Y do not satisfy the expression (1), and Y <
In the case of 0.44X, the melt viscosity of the polyamide composition after mixing greatly exceeds the melt viscosity of the raw material polyamide before mixing, resulting in a composition having poor moldability, which is not preferable. The composition in which the polyamide-based composition after mixing satisfies Y ≧ 0.44X is a polyamide having different terminal amino group concentrations and terminal carboxyl group concentrations of the polyamide to be mixed, and polyamides having different phosphorus atom concentrations. It can be obtained by selecting the type, the mixing ratio of a plurality of polyamides and the like.

There is no upper limit to the respective values of the terminal group concentration difference Y and the phosphorus atom concentration X of the polyamide-based composition according to the present invention. However, if both values are too large, the melt viscosity is significantly lowered, and the polyamide-based composition When a molded product is manufactured by an extrusion molding method using the composition as a raw material, the amount of extrusion tends to be unstable, which may cause a problem such as difficulty in securing the thickness accuracy of the sheet or film. , In general, Y
Is 100 × 10 ⁻⁶ equivalent / g or less, preferably 80 × 10
^-6 equivalents / g or less, and X is 100 ppm or less, preferably 40 ppm or less.

The polyamide-based composition according to the present invention is selected from a plurality of polyamides by selecting and combining two or more kinds, and any kind of polyamide-based composition may be used as long as the mixed polyamide-based composition satisfies the above requirements. Combinations may be used, and the type of raw material polyamide is not particularly limited. Specific examples of the raw material polyamides include polyamides obtained by ring-opening polymerization of lactams such as ε-caprolactam, enantolactam, and lauryllactam; Polyamide obtained by condensation, polyamide obtained by polycondensation of nylon salt of diamine and dicarboxylic acid, further, various lactams described above, aminocarboxylic acid, a mixture of nylon salt of diamine and dicarboxylic acid as appropriate. Examples thereof include polyamide copolymers obtained by copolycondensation. Specific examples of the diamine include ethylenediamine, trimethylenediamine, hexamethylenediamine, metaxylylenediamine, paraxylylenediamine, cyclohexanediamine, aliphatic diamines such as 1,3-bisaminomethylcyclohexane, and alicyclic diamines. To be Specific examples of dicarboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, aliphatic dicarboxylic acids such as phthalic acid, alicyclic dicarboxylic acids, and aromatics. Group dicarboxylic acids and the like. Further, in the present invention, even when the above-mentioned various polyamides are manufactured, those having modified terminal groups and different terminal group concentrations are treated as different polyamides. For example, what modified the terminal group at the time of manufacturing polycapramide is treated as different from unmodified polycapramide.

The polyamide used in the present invention is produced by a known method. For example, it is produced by a method in which lactam is heated under pressure in the presence of a water solvent and polymerized while removing added water and condensed water. Further, it is produced by a method in which a nylon salt composed of a diamine and a dicarboxylic acid is heated under pressure in the presence of a water solvent and polymerized while removing added water and condensed water. Further, it is also produced by a method of directly adding diamine to molten dicarboxylic acid and polycondensing under normal pressure. In either case, a polymer having a high molecular weight obtained by melt polymerization and then solid phase polymerization can also be used.

The relative viscosity of the raw material polyamide used in the present invention (value measured by dissolving 1 g of polyamide in 100 ml of 96% sulfuric acid at 25 ° C.) is 1.7 to 5.5, particularly 1.9.
It is preferably in the range of 5.0. Relative viscosity is 1.
When it is less than 7, the polyamide has a low molecular weight, does not exhibit the necessary mechanical strength when formed into a molded article such as a film, and has a low melt viscosity, which causes a problem during molding. When the relative viscosity exceeds 5.5, the polyamide has a high melt viscosity, which imposes a heavy load on the molding machine during molding and makes mixing difficult, which is not preferable as a raw material of the present invention.

Further, the polyamide composition according to the present invention contains a lubricant, an antistatic agent, an antioxidant, an antiblocking agent, a stabilizer, within a range that does not significantly change the melt viscosity.
Various additives such as dyes, pigments and inorganic fine particles, and other thermoplastic resins can be added. Further, a modified polyolefin, an ionomer resin, an elastomer or the like may be added in order to improve the flex resistance etc. within a range in which the melt viscosity of the polyamide composition is not significantly changed.

Examples of the phosphorus compound in the present invention include phosphoric acid, hypophosphorous acid, phosphorous acid, and metal salts and partially neutralized salts thereof. In this case, the metal of the metal salt is potassium, sodium, calcium, magnesium or the like. The polyamide-based composition according to the present invention is a dry-blended product, or a melt-blended product that has been melt-mixed in advance with an extruder or the like and then pelletized, and various molding techniques such as an injection molding method, an extrusion molding method, and a blow molding method. The desired final molded product can be molded by Examples of molded articles include automobile parts, machine equipment parts, sheets, films (single layer, multi-layer), laminates with paper, blow bottles and the like, and secondary processed articles include trays, pouches and the like. Furthermore, in order to enhance the mechanical strength of the polyamide composition according to the present invention, glass fiber, carbon fiber, calcium carbonate,
Fibers or fillers such as mica and potassium titanate can be added and used as a molding material.

[0019]

EXAMPLES The contents and effects of the present invention will be described below in more detail with reference to examples, but the present invention is not limited to the examples described below as long as the gist thereof is not exceeded. In addition,
The terminal group concentration, phosphorus atom concentration, melt viscosity, and relative viscosity of the polyamides used in the following Examples and Comparative Examples and the polyamide-based compositions obtained by mixing these are those measured by the following methods. .

<Terminal group concentration> Using an automatic titrator GT-01 manufactured by Mitsubishi Kasei Co., Ltd., dissolved in a mixed solution of phenol and ethanol, hot benzyl alcohol, etc., the terminal amino group concentration is hydrochloric acid aqueous solution, terminal carboxy. The concentration was measured with an aqueous sodium hydroxide solution. <Phosphorus Atom Concentration> After wet ashing 1 g of the sample, 2,4 dinitrophenol pH indicator was added dropwise, ammonia water was added until a slight yellow color was obtained, and vanadomolybdic acid was further added to 10 g.
After adding ml, water was added and weighed to 25 ml, allowed to stand for 20 minutes or more, and then analyzed by an absorptiometer.

<Melt Viscosity> A melt rheometer (capillary L / D = 40) manufactured by Instron was used at a resin temperature of 270 ° C. and a shear rate of 100 sec ⁻¹ . <Relative Viscosity> Using a Canon Fenske type viscometer, 1 g of the sample was dissolved in 100 ml of 96% sulfuric acid and measured at 25 ° C.

Polycapramide A 200 l autoclave was charged with ε-caprolactam 60.
61.6g of Kg, 1.2Kg of water and hexamethylenediamine
Was charged, the mixture was sealed in a nitrogen atmosphere, the temperature was raised to 260 ° C., the reaction was carried out under pressure for 2 hours while stirring, and then the pressure was gradually released to 200 torr and the reaction was carried out under reduced pressure for 2 hours.
After introducing nitrogen and restoring the pressure to normal pressure, stirring was stopped, the reaction product was extracted as strands from the autoclave and made into chips, and unreacted monomers were extracted and removed using boiling water and dried to produce polycapramide A. . The [terminal amino group concentration] of this product was 37 × 10 ⁻⁶ equivalent / g, the [terminal carboxyl group concentration] was 4 × 10 ⁻⁶ equivalent / g, the phosphorus atom concentration was 0 ppm, the melt viscosity was 2800 poise, and the relative viscosity was It is 3.5.

Polycapramide B 200 l of autoclave, ε-caprolactam 60
Kg, 3 kg of water and 219 g of adipic acid were charged, the atmosphere was replaced with nitrogen, and then the reaction was carried out under pressure at 270 ° C. under a pressure of 8 kg for 1 hour. Then release the pressure, reduce the pressure to 150 torr,
The reaction was performed under reduced pressure for 2 hours, the stirring was stopped, the pressure was restored to 8 kg with nitrogen, and the reaction product was extracted as a strand from the autoclave. The extracted strand was cut into chips, extracted with demineralized water to remove unreacted monomers and oligomers, and dried to produce polycapramide B. The [terminal amino group concentration] of this product was 7 × 10 ⁻⁶ equivalent / g, the [terminal carboxyl group concentration] was 55 × 10 ⁻⁶ equivalent / g, the phosphorus atom concentration was 0 ppm, and the melt viscosity was 28.
00 poise, relative viscosity 3.5.

Polycapramide C 200 l autoclave, ε-caprolactam 60
After charging Kg and 1.2 Kg of water, sealing in a nitrogen atmosphere, raising the temperature to 260 ° C., reacting under pressure for 2 hours with stirring, and then gradually releasing the pressure to 200 torr and reducing the pressure for 2 hours. The reaction was carried out. After introducing nitrogen and returning to normal pressure, stirring was stopped, the reaction product was extracted as strands from the autoclave and made into chips, and unreacted monomers were extracted and removed using boiling water and dried to produce polycapramide C. . The [terminal amino group concentration] of this product was 29 × 10 ⁻⁶ equivalent / g, the [terminal carboxyl group concentration] was 28 × 10 ⁻⁶ equivalent / g, the phosphorus atom concentration was 0 ppm, and the melt viscosity was 60.
00 poise, relative viscosity is 3.7.

Polyhexamethylene adipamide Leona 66 manufactured by Asahi Kasei Kogyo Co., Ltd. The [terminal amino group concentration] of this product was 30 × 10 ⁻⁶ equivalent / g, the [terminal carboxyl group concentration] was 113 × 10 ⁻⁶ equivalent / g, the phosphorus atom concentration was 100 ppm, and the melt viscosity was 6000.
Poise, relative viscosity is 3.3.

Polymetaxylene adipamide A In a flask with an internal volume of 3000 cc equipped with a stirrer, a partial condenser, a thermometer, a dropping funnel and a nitrogen gas introducing tube, 731 g of adipic acid precisely weighed and sodium hypophosphite ( 0.6 g of (monohydrate salt) was added thereto, the atmosphere was sufficiently replaced with nitrogen, and the resulting mixture was uniformly dissolved at 160 ° C. in a small amount of nitrogen stream. To this, 612.9 g of meta-xylene diamine was added dropwise with stirring over 50 minutes. During this time, the internal temperature was continuously raised to 223 ° C. Subsequently, 68.1 g of meta-xylenediamine was continuously added dropwise under stirring for 20 minutes. During this time, the reaction temperature is 2
The temperature was continuously raised from 23 ° C to 243 ° C. Water distilled along with the addition of meta-xylenediamine was removed from the system through a partial condenser and a cooler. After the addition of meta-xylenediamine was completed, the internal temperature was raised to 260 ° C. and the reaction was continued for 2 hours. During the whole process of the reaction, no phenomenon of solidification or precipitation of the produced oligomer or polyamide was observed, and a uniform molten state was maintained throughout. The [terminal amino group concentration] of the obtained polymeta-xylene adipamide was 12 × 10 ⁻⁶ equivalent /
g, [terminal carboxyl group concentration] is 61 × 10 ⁻⁶ equivalent /
and the phosphorus atom concentration is 120 ppm and the water content is adjusted to 0.02%, the melt viscosity is 4800 pois.
e, relative viscosity is 2.6.

Polymetaxylene adipamide B In the production method described in Polymetaxylene adipamide A,
The reaction was performed in place of 0.025 g of sodium hypophosphite (monohydrate salt). [Terminal amino group concentration] of the obtained polymetaxylene adipamide was 12 × 10 ⁻⁶ equivalent / g, and [terminal carboxyl group concentration] was 61 × 10 ⁻⁶ equivalent / g,
Although the phosphorus atom concentration was 5 ppm and the water content was adjusted to 0.02%, the melt viscosity was 4800 poise and the relative viscosity was 2.
It is 6.

Polymetaxylene adipamide C In the production method described in Polymetaxylene adipamide A,
The reaction was performed in place of 0.05 g of sodium hypophosphite (monohydrate salt). [Terminal amino group concentration] of the obtained polymetaxylene adipamide was 12 × 10 ⁻⁶ equivalent / g, and [terminal carboxyl group concentration] was 61 × 10 ⁻⁶ equivalent / g,
Although the phosphorus atom concentration was 10 ppm and the water content was adjusted to 0.02%, the melt viscosity was 4800 poise and the relative viscosity was 2.6.

Example 1 A resin composition prepared by mixing polycapramide B and polyhexamethylene adipamide A in a mixing ratio (weight ratio) of 60:40 was used, and the resin temperature was 270 ° C. using an extruder equipped with a strand die. Was melt-kneaded and extruded into pellets. For the obtained pellets, the terminal amino group concentration, terminal carboxyl group concentration, phosphorus atom concentration and melt viscosity were measured,
The results are shown in Table 1 together with the types and ratios of polyamides used and the measured values of melt viscosity. There was no increase in viscosity during melt kneading, and extrusion moldability was good.

Examples 2 to 6 and Comparative Examples 1 to 4 Melt kneading was carried out in the same manner as in Example 1 except that the kind and mixing ratio of polyamide in the example described in Example 1 were changed as shown in Table 1. Pelletized. For the obtained pellets, terminal amino group concentration, terminal carboxyl group concentration,
The phosphorus atom concentration and the melt viscosity were measured, and the results are shown in Table 1 together with the types of polyamide used, the ratio, and the measured values of the melt viscosity. The compositions of Examples 2 to 6 had no increase in viscosity during melt kneading, and had good extrusion moldability. The compositions of Comparative Examples 1 to 4 showed a large increase in viscosity during melt kneading.

[0031]

[Table 1]

In Table 1, each abbreviation has the following meaning. NH ₂ : Terminal amino group concentration COOH: Terminal carboxyl group concentration

[0033]

The polyamide composition according to the present invention has 2
The composition obtained by melt-mixing more than one kind of polyamide can suppress the increase of melt viscosity, has excellent moldability, and has a particularly remarkable effect that troubles due to increase of melt viscosity do not occur. The above utility value is extremely high.

Continuation of the front page (72) Inventor Kunio Takeda 1000 Higashiuiana-cho, Ushiku-shi, Ibaraki Mitsubishi Kasei Co., Ltd. Tsukuba factory

Claims (2)

[Claims] 1. A polyamide composition comprising a mixture of two or more polyamides, wherein a difference Y in terminal concentration of the polyamide after mixing and a phosphorus atom concentration X in the polyamide after mixing.
Which satisfies the following formula (1): ## EQU1 ## Y ≧ 0.44X (1) (where Y is | [terminal amino group concentration] − [terminal carboxyl group concentration] | × 10 ⁻⁶ (equivalent / g), X is phosphorus atom concentration] (Ppm) is shown.) 2. A polyamide composition comprising a mixture of two or more polyamides, wherein at least one polyamide has 70 mol% or more of structural units formed by a polycondensation reaction of metaxylylenediamine and adipic acid. It is a polyamide or a polyamide copolymer contained, and the terminal atom concentration difference Y of the polyamide after mixing and the phosphorus atom concentration X of the polyamide after mixing satisfy the formula (1). The polyamide composition described.