JP3270518B2 - Polyamide resin composition and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamide resin composition and a method for producing the same, and more particularly, to a polyamide resin composition excellent in rigidity, lightness, surface smoothness of a molded article and color tone, and production thereof. It is about the method.

[0002]

2. Description of the Related Art Polyamide resins are widely used as representative engineering plastics in the fields of automobile parts, electric / electronic parts, and mechanical parts because of their excellent toughness, oil resistance, wear resistance, and light weight. ing. However, the polyamide resin has lower rigidity than other resins, for example, polyphenylene sulfide resin, and thus its use in fields requiring rigidity is limited.

[0003]

As a method for improving the rigidity of a polyamide resin, there is known a method of adding an inorganic crystal nucleating agent such as talc or a reinforcing material such as glass fiber. However, a method of adding an inorganic crystal nucleating agent does not provide a sufficient effect of improving rigidity, and a method of adding glass fiber inevitably causes an increase in specific gravity and a decrease in surface smoothness of a molded product. The inventors of the present invention have been made in view of the above circumstances, and an object of the present invention is to provide a polyamide resin composition having excellent rigidity, light weight, surface smoothness of a molded article, and color tone, and a method for producing the same.

[0004]

That is, the present invention relates to a polyamide resin composition and a method for producing the same, and the gist of each invention is as follows. The first gist of the present invention is as follows.
(4) that the layered phosphate derivative of a tetravalent cation and / or the layered phosphoric acid / phosphorous acid mixed salt derivative of a tetravalent cation having an interlayer distance of not less than an interlayer distance is dispersed in a polyamide resin at a unit layer level. It is a characteristic polyamide resin composition. A second gist of the present invention is to provide a layered phosphate of a tetravalent cation and / or a layered phosphate of a tetravalent cation in water or an aqueous solution of a linear ω-amino acid having 6 or more carbon atoms.
A method for producing a polyamide resin composition, comprising dispersing a layered salt derivative prepared by dispersing a mixed salt of phosphorous acid in a polyamide monomer and then performing polymerization.

Hereinafter, the present invention will be described in detail. First, the polyamide resin composition of the present invention will be described. The polyamide resin composition of the present invention comprises a polyamide resin and a layered phosphate derivative of tetravalent cation and / or a layered phosphoric acid / phosphorous acid mixed salt derivative.

[0006] Polyamide resin has -C in the polymer main chain.
It is a resin having an O-NH- bond and capable of being melted by heating. In the present invention, a preferable polyamide resin is polytetramethylene adipamide (nylon 4/6)
, Polycaprolactam (nylon 6), polyhexamethylene adipamide (nylon 6/6), polyhexamethylene sebacamide (nylon 6/10), polyhexamethylene dodecamide (nylon 6/12), polydodecalactam (nylon 6/10) Nylon 12).

In addition to the above, a polyamide obtained from terephthalic acid and / or isophthalic acid and hexamethylenediamine, a polyamide obtained from adipic acid and hexamethylenediamine, and a polyamide obtained from terephthalic acid, adipic acid and hexamethylenediamine Suitable semi-aromatic polyamides, copolymerized polyamides containing a dimerized fatty acid as a copolymerization component, and the like are also mentioned as suitable polyamide resins.

In the present invention, a tetravalent cation layered phosphate is defined as a tetravalent cation arranged on the same plane, which is crosslinked by a phosphate group (PO ₄ ), and the four oxygen atoms of each phosphate group. Three of them participate in cross-linking with tetravalent cations to form an octahedral configuration of six oxygen atoms around the tetravalent cation, and the negative charge of the remaining oxygen atoms of each phosphate group is hydrogen ion Means a structure neutralized by the positive charge of Further, the layered phosphoric acid / phosphorous acid mixed salt of a tetravalent cation means a structure in which a part of the phosphate group in the above layered phosphate is substituted by a phosphite group (PO ₃ ).

The above-mentioned layered salt is prepared by adding a high-concentration aqueous solution of phosphoric acid, phosphoric acid and phosphorous acid or a water-soluble salt thereof to an aqueous solution containing a tetravalent cation such as titanium, zirconium or tin. The resulting amorphous gel is synthesized by heating with the mother liquor. As a method of synthesizing a layered salt,
Many modifications other than the above are known, and in the present invention, a layered salt can be synthesized by not only the above-mentioned synthesis but also various modifications.

Examples of the tetravalent cation layered phosphate and / or the tetravalent cation layered phosphoric acid / phosphorous acid mixed salt include α-titanium phosphate, β-titanium phosphate, γ -Titanium phosphate, ammonium ion exchanger of titanium phosphate, ammonium ion exchanger of titanium phosphate / phosphite, α-zirconium phosphate, β-zirconium phosphate, γ-zirconium phosphate, γ-zirconium phosphate , Phosphoric acid / zirconium phosphite, α-tin phosphate, phosphoric acid / tin phosphite and the like. In the above, α-type means a crystal structure in which a lower metal atom is located immediately below a phosphorus atom, β-type means a crystal structure in which a lower phosphorus atom is located immediately below a phosphorus atom, and γ-type means the above crystal structure. It means a crystal structure with a water molecule layer between the β-type layers.

By the way, elements of the 4A and 4B groups of the periodic table,
As for cerium and thorium, the above-mentioned layered salts are known. It is also known that arsenic acid (H ₃ AsO ₄ ) and arsenous acid (H ₃ AsO ₃ ) can be used instead of phosphoric acid and phosphorous acid to produce the same layered salt as described above. Therefore, in principle, it is expected that the same resin composition as that of the present invention can be obtained by the layered salt obtained from each of the above components. However, in the present invention, a layered salt obtained from any of titanium, zirconium and tin and phosphoric acid or phosphorous acid is preferably used from the viewpoints of compound stability, availability of raw materials, and safety. Is done.

In the present invention, the above-mentioned layered salt derivative has a structure in which part or all of the hydrogen ions neutralizing the negative charge of the oxygen atom of the phosphate group is replaced by a cation other than a hydrogen ion. means. The interlayer distance of the above-mentioned layered salt derivative needs to be 15 ° or more. Interlayer distance is 1
If it is less than 5 °, the rigidity of the resin composition cannot be sufficiently improved. Although the reason for this is not clear, it is presumed that a small interlayer distance hinders the penetration of the polyamide monomer between the layers, resulting in that the dispersion of the layered salt derivative at the unit layer level is not achieved. The upper limit of the interlayer distance is not particularly limited, but is usually 2000 °.

The layered salt derivative having an interlayer distance as described above is, for example, a layered phosphate of a tetravalent cation and / or a layered phosphate of a tetravalent cation in water or an aqueous solution of a linear ω-amino acid. It can be easily prepared by dispersing an acid / phosphorous acid mixed salt. That is, long hydrogen bonding and van der Wa
A linear ω-amino acid penetrates between the layers of the layered salt relatively loosely bound by the als force, and the amino group neutralizes the strongly acidic OH group bonded to the phosphorus atom to form a ω-carboxy linear alkylammonium. It is believed that a salt derivative is formed.
As a result, the interlayer distance increases according to the chain length of the linear alkyl. The aqueous solution in the above dispersion treatment is used when the linear ω-amino acid has insufficient water solubility. The aqueous solution is prepared by adding an appropriate water-soluble organic solvent to water.

When the interlayer distance is to be increased by using a linear ω-amino acid, a linear ω-amino acid having 6 or more carbon atoms is used.
It is important to use amino acids. When a linear ω-amino acid having less than 6 carbon atoms is used, the effect of increasing the interlayer distance of the layered salt is not sufficient, and the object of the present invention cannot be achieved. And the upper limit of the carbon number of the linear ω-amino acid is
Although not particularly limited, it is usually 20 from the viewpoint of solubility in water or an aqueous solution. The preferred carbon number of the linear ω-amino acid is in the range of 6-15.

Specific examples of linear ω-amino acids having 6 or more carbon atoms include 6-aminohexanoic acid, 7-aminoheptanoic acid, 8-aminooctanoic acid, 9-aminononanoic acid,
10-aminodecanoic acid, 11-aminoundecanoic acid, 1
2-aminododecanoic acid, 13-aminotridecanoic acid, 1
4-aminotetradecanoic acid and 15-aminopentadecanoic acid. In particular, from the viewpoint of the effect of increasing the interlayer distance, water solubility, and availability, 10-aminodecanoic acid,
2-Aminododecanoic acid is preferably used.

It is necessary that the above-mentioned layered salt derivative is dispersed in the polyamide resin at a unit layer level. If the layered salt derivative is not dispersed at the unit layer level, the effect of improving the mechanical properties of the polyamide resin composition is not sufficient, and the object of the present invention cannot be achieved. Here, the dispersion of the layered salt derivative at the unit layer level means that a unit layer composed of tetravalent cations arranged on the same plane and a phosphate group or a phosphite group coordinated with the tetravalent cations is formed through hydrogen ions. It means a state in which the interaction between the unit layers due to the long hydrogen bond and the Van der Waals force is significantly reduced or substantially eliminated, and is uniformly dispersed in the polyamide resin.

The dispersion at the unit layer level of the layered salt derivative in the polyamide resin composition can be confirmed by disappearance of a diffraction peak corresponding to the interlayer distance of the layered salt derivative in the wide-angle X-ray diffraction spectrum of the polyamide resin composition. FIG. 1 is a structural model of a unit layer of α-zirconium phosphate shown for reference. In the figure, black circles represent oxygen atoms, and circles shown by broken lines represent linear ω-amino acids.

In the polyamide resin composition of the present invention,
The content of the layered salt derivative is preferably in the range of 0.5 to 40% by weight, and most preferably in the range of 2 to 15% by weight. When the content of the layered salt derivative is less than 2% by weight, the effect of improving the rigidity of the polyamide resin composition is insufficient, and the content is 15% by weight.
If it exceeds, the surface smoothness of the molded product is extremely reduced,
In any case, the object of the present invention cannot be achieved.

The polyamide resin composition of the present invention may contain an inorganic filler in an amount of 50% by weight or less, preferably 10 to 35% by weight of the total composition for the purpose of further improving rigidity. is there. And as the inorganic filler,
Glass fiber, glass flake, glass beads, talc,
Examples include mica, clay, calcium carbonate, calcium sulfate, and the like.

The polyamide resin composition of the present invention can be blended with other components by melt mixing as in the case of ordinary nylon 6 resin. Specific examples of the blend component include thermoplastic resins and elastomers exemplified in the following (1) to (8).

(1) Polyolefin resin For example, polyethylene resin, polypropylene resin, polybutene resin and the like can be mentioned. (2) Modified olefin polymer Examples of the olefin polymer include ethylene polymer, propylene polymer, butadiene polymer, isoprene polymer, isobutylene polymer, ethylene-propylene copolymer, ethylene-propylene-butadiene copolymer, and ethylene. -Butadiene copolymer, ethylene-butene copolymer, isobutylene-butadiene copolymer and the like are used. As the modifier, a graftable carboxylic acid derivative such as maleic anhydride and / or a graftable epoxy group-containing compound such as glycidyl methacrylate is used.

(3) Polyamide resin For example, polytetramethylene adipamide (nylon 4
6) Resin, polyhexamethylene adipamide (nylon 6
6) Resin, polyhexamethylene sebacamide (nylon 6
10) Resin, polyhexamethylene dodecamide (nylon 612) Resin, polyundecalactam (nylon 11)
, Polydodecalactam (nylon 12), polyamide resin obtained from terephthalic acid and hexamethylenediamine, polyamide resin obtained from adipic acid and metaxylenediamine, polyamide resin obtained from terephthalic acid, adipic acid and hexamethylenediamine And a copolymerized polyamide containing a dimerized fatty acid as a copolymerization component.

(4) Aromatic polycarbonate resin Representatively, bisphenol A polycarbonate resin and the like are mentioned. (5) Aromatic polyester resin For example, polyethylene terephthalate (PET) resin,
Examples include polybutylene terephthalate (PBT) resin, polyester (PCT) resin obtained from terephthalic acid and p-cyclohexanedimethanol, and polyester resin obtained from bisphenol A and phthalic acid.

(6) Other resins For example, polyphenylene ether resin, acid-modified polyphenylene ether resin, polyphenylene sulfide resin,
Examples include phenolic resins, epoxy resins, and styrene-maleic anhydride copolymers obtained by copolymerizing maleic anhydride. (7) Polyamide-based thermoplastic elastomer For example, polyether amide elastomer, polyester amide elastomer and the like can be mentioned.

(8) Modified styrene-based thermoplastic elastomer The styrene-based thermoplastic elastomer includes butadiene rubber-modified polystyrene, butadiene rubber-modified styrene-acrylonitrile copolymer, acrylic rubber-modified polystyrene, and acrylic rubber-modified styrene-acrylonitrile copolymer. Coalesce, ethylene-propylene copolymer-modified polystyrene, ethylene-butene copolymer-modified polystyrene,
Hydrogenated ethylene-butadiene copolymer-modified polystyrene, isoprene rubber-modified polystyrene, ethylene-methyl methacrylate copolymer-modified polystyrene, and the like are used. As the modifier, a graftable carboxylic acid derivative such as maleic anhydride and / or a graftable epoxy group-containing compound such as glycidyl methacrylate is used.

Next, a method for producing the polyamide resin composition of the present invention will be described. The polyamide resin composition of the present invention can be produced by dispersing a predetermined amount of the above-mentioned layered salt derivative in a polyamide monomer and then performing polymerization. As the polyamide monomer, the following polyamide monomers (a) to (c) corresponding to the above-mentioned polyamide resin are used. (A) Diamine and dicarboxylic acid (b) Diamine, dicarboxylic acid and lactam (c) Lactam

As the diamine, specifically,
Aliphatic chains such as trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, octamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4- or 2,4,4-trimethylhexamethylenediamine Diamine having an aromatic ring such as linear diamine, phenylenediamine and xylylenediamine; and alicyclic diamine such as bis (4-amino-3-methylcyclohexyl) methane.

Specific examples of the dicarboxylic acid include aromatic chain dicarboxylic acids such as adipic acid, pimelic acid, glutaric acid, suberic acid, octadecandioic acid and sebacic acid, and aromatic compounds such as terephthalic acid and isophthalic acid. Aromatic dicarboxylic acids, cyclohexane-1,4- and 1,3-
Examples include alicyclic dicarboxylic acids such as dicarboxylic acids and dimerized fatty acids. Here, the dimerized fatty acid is a fatty acid, for example, a polymerized fatty acid obtained by polymerizing a saturated, ethylenically unsaturated, acetylenically unsaturated, natural or synthetic-basic fatty acid having 8 to 24 carbon atoms.

Examples of the lactam include butyl lactam, pivalolactam, caprolactam, caprylactam, enantholactam, undecanolactam, dodecalactam and the like. These lactams may be used in combination of two or more.

Among the above-mentioned polyamide monomers, fatty acids such as tetramethylenediamine, hexamethylenediamine, adipic acid and sebacic acid are preferred from the viewpoints of penetration of the layered salt derivative between layers, easiness of polymerization reaction and availability. Lactams such as group-chain monomers, caprolactam and dodecalactam are preferred. Particularly, a combination of hexamethylenediamine and adipic acid or caprolactam is preferable, and caprolactam is most preferable.

The dispersion of the layered salt derivative in the polyamide monomer is performed in an aqueous solution of a salt of a diamine and a dicarboxylic acid or in a lactam melt. In some cases, it is preferable to appropriately heat the dispersion system in order to promote penetration of the layered salt derivative of the polyamide monomer between layers. When the dispersion is carried out in a lactam melt, it is preferable to add a polymerization initiator such as aminocarboxylic acid at this stage. The polymerization of the polyamide monomer is performed according to a known method, and the polymerization method is not particularly limited.

[0032]

The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples unless departing from the gist thereof. In the following examples, physical properties were measured according to the following methods. (1) Measurement of interlayer distance “Rotaflex RU-200” manufactured by Rigaku Denki Co., Ltd.
The measurement was performed using a "BV type" X-ray irradiator (X-ray wavelength: 1.5406 °).

(2) Evaluation of rigidity The resin composition was press-molded at 285 ° C. to prepare a 1 mm-thick plate, which was immediately quenched in ice water, punched out in the form of dumbbell pieces, and placed in a vacuum oven at 100 ° C. Crystallization was achieved by annealing for 16 hours. Then, a tensile test was performed at a speed of 5 mm / min in a completely dry state, and the tensile modulus was measured. FIG. 2 is an explanatory view of the dumbbell piece used for the rigidity evaluation. The reference tensile modulus was calculated based on the dimensions of the rectangular parallelepiped portion (b) in the neck portion (a) of the dumbbell piece before tension. (3) Evaluation of Surface Smoothness The surface smoothness of the above-mentioned dumbbell pieces was evaluated by visual observation.

Example 1 200 g of 2 g of α-titanium phosphate (interlayer distance: 7.4 °)
of water (85 ° C.) and add 12-
2.16 g of aminododecanoic acid was added and stirred for 6 hours. After the stirring was stopped and the mixture was allowed to stand at room temperature for 10 days, the solid was separated by filtration. The obtained solid was suspended in 1 liter of water with stirring, and then filtered again for washing. 5 washing operations
Repeated times. The washed solid was dried in a vacuum oven at 50 ° C. for 16 hours, and then ground in a mortar.

The 12-aminododecanoic acid derivative of α-zirconium phosphate obtained by the above operation (interlayer distance 22.0 °)
1.25 g of 22.38 g of ε-caprolactam and 6-
Crushed and mixed in a mortar with 2.37 g of aminohexanoic acid,
It was charged into a glass polymerization tube. After replacing the inside of the polymerization tube with nitrogen,
Stir at 100 ° C. for 90 minutes, raise the temperature to 250 ° C., at atmospheric pressure for 2 hours, and then under reduced pressure (maximum degree of vacuum 0.3 Torr)
For 5 hours. After the obtained polyamide resin composition was pulverized, it was thrown into boiling water to extract residual low molecular weight substances. The polyamide resin composition after the extraction treatment was dried in hot air drying at 80 ° C. for 2 hours, and further dried in vacuum drying at 100 ° C. for 18 hours. Physical properties of the polyamide resin composition obtained by the above operation were measured, and the results are shown in Table 1.

Example 2 2 g of α-zirconium phosphate (interlayer distance: 7.4 °)
The same operation as in Example 1 was carried out except that the suspension was suspended in 00 ml of water (55 ° C.) and 2.16 g of 12-aminododecanoic acid was added to the resulting suspension and stirred for 2 hours. A polyamide resin composition was obtained. Physical properties of the polyamide resin composition obtained by the above operation were measured, and the results are shown in Table 1. The interlayer distance of the 12-aminododecanoic acid derivative of α-zirconium phosphate was 18.0 °.

Example 3 2 g of γ-zirconium phosphate (interlayer distance 12.2 °) was suspended in 200 ml of water (55 ° C.), and 2.16 g of 12-aminododecanoic acid was added to the resulting suspension. A polyamide resin composition was obtained by performing the same operation as in Example 1 except that stirring was performed for 2 hours. Physical properties of the polyamide resin composition obtained by the above operation were measured, and the results are shown in Table 1. The interlayer distance of the 12-aminododecanoic acid derivative of γ-zirconium phosphate was 28.2 °.

EXAMPLE 4 Zirconium phosphate / phosphite [Zr (HPO ₄ ) _0.7
(HPO ₃ ) _1.3 · 0.5 H ₂ O] (interlayer distance 12.8)
Ii) The same operation as in Example 1 except that 2 g was suspended in 200 ml of water (55 ° C), and 2.16 g of 12-aminododecanoic acid was added to the resulting suspension and stirred for 2 hours. Was performed to obtain a polyamide resin composition. Physical properties of the polyamide resin composition obtained by the above operation were measured, and the results are shown in Table 1. The interlayer distance of the 12-aminododecanoic acid derivative of phosphoric acid / zirconium phosphite is 27.6.
Was Å.

Comparative Example 1 22.5 g of ε-caprolactam and 2.5 g of 6-aminohexanoic acid were pulverized and mixed in a mortar and charged into a glass polymerization tube. Thereafter, the same operation as in Example 1 was performed to obtain a polyamide resin. Physical properties of the polyamide resin obtained by the above operation were measured, and the results are shown in Table 1.

Comparative Example 2 α-zirconium phosphate (interlayer distance: 7.4 °) 1.25
g was mixed with 22.38 g of ε-caprolactam and 2.37 g of 6-aminohexanoic acid in a mortar and charged into a glass polymerization tube. Thereafter, the same operation as in Example 1 was performed to obtain a polyamide resin composition. Physical properties of the polyamide resin composition obtained by the above operation were measured, and the results are shown in Table 1. The interlayer distance of α-zirconium phosphate was 7.4 ° after pulverization and mixing in a mortar.

[0041]

[Table 1] ──────────────────────────────── Experiment number Tensile modulus (kg / cm ² ) Surface smoothness例 Example 1 15900 Good Example 2 15130 Good Example 3 14760 Good Example 4 14880 Good Comparative Example 1 12300 Good Comparative Example 2 12840 There is a white foreign substance. ──

[0042]

According to the present invention described above, there is provided a polyamide resin composition having excellent rigidity, light weight, surface smoothness and color tone of a molded product, and an effective method for producing the same. And the polyamide resin composition of the present invention, in particular,
It is suitable as a molding material in a field requiring rigidity.

[Brief description of the drawings]

FIG. 1 is a structural model of a unit layer of α-zirconium phosphate.

FIG. 2 is an explanatory diagram of a dumbbell piece used for rigidity evaluation.

[Explanation of symbols]

 (A): neck (b): rectangular parallelepiped

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08L 77/00-77/12

Claims (3)

(57) [Claims] 1. A layered phosphate derivative of a tetravalent cation and / or a layered phosphoric acid / phosphorous acid mixed salt derivative of a tetravalent cation having an interlayer distance of 15 ° or more is dispersed at a unit layer level in a polyamide resin. A polyamide resin composition comprising: 2. The polyamide resin composition according to claim 1, wherein the polyamide resin is nylon 6. 3. A layered phosphate of a tetravalent cation and / or a mixed layer of phosphoric acid and phosphorous acid of a tetravalent cation in water or an aqueous solution of a linear ω-amino acid having 6 or more carbon atoms. A method for producing a polyamide resin composition, comprising dispersing a layered salt derivative prepared by dispersing in a polyamide monomer, followed by polymerization.