JP4526911B2 - Polyamide master batch pellet - Google Patents

Description

  The present invention relates to a polyamide masterbatch pellet which can eliminate the trouble of metal deposition during processing and can provide a polyamide molded article having excellent heat resistance and appearance, or a polyamide molded article using the same.

Polyamide resins are used in many applications in the automotive and electrical / electronic fields, taking advantage of their excellent mechanical properties, heat resistance, chemical resistance, flame resistance, and the like. Among these, polyamide resins are excellent in long-term heat aging resistance as not seen in other resins, and are therefore used in parts where heat at extremely high temperatures is applied, such as in automobile engine rooms. Particularly in recent years, with the increase in the density of automobile engine compartment parts and the increase in engine output, the environmental temperature in the engine compartment has become increasingly high, and higher long-term heat aging resistance than ever has been required of polyamide resins. It was.
In response to this, various technical improvements have been attempted so far, for example, a polyamide resin composition containing a copper halogen compound, an aromatic amine, and a polyamide resin composition containing a hindered phenol-based oxidative degradation inhibitor. Etc. Among these, the heat aging improving technology using a mixture of a copper compound and a halogen compound is particularly excellent in cost performance, and is still widely used today.

  As a method of blending a copper compound and a halogen compound into a polyamide resin, an aqueous solution containing the copper compound and the halogen compound is prepared, and at any time before, during or after the polymerization of the polyamide (blending or melting with the polyamide resin) The method of adding to kneading | mixing etc. is mentioned. The method to be added before or during the polymerization is desirable for uniformly dispersing the copper compound and the halogen compound. However, production such as generation of an intermediate product or the need to wash the polymerization apparatus is required at the time of brand switching. It will cause a decrease in efficiency. Master batch pellets containing copper compounds and halogen compounds have also been proposed in order to improve production efficiency, but the conventional method reduces the mechanical properties because the dispersibility is lower than the method of adding in the polymerization step. The problem arises. Further, there is a problem in that the appearance of the molded product is deteriorated by changing the color from white to green in the process of gradually absorbing water thereafter, and the color change increases as the copper concentration increases.

In order to improve the copper precipitation and the dispersibility of the halogen compound, compositions using various compounds in combination have been proposed. In particular, halogen compounds are known to be easily agglomerated and solidified, but they can be added in a fine powder state by adding a lubricant to the halogenated compound by pulverization or the like in advance to prevent aggregation and solidification. It has been proposed to improve the appearance (see, for example, Patent Document 1).
In addition, it has been proposed to blend a masterbatch composed of a polyamide compound, a copper compound, and a halogen compound other than copper halide with respect to the polyamide (see, for example, Patent Document 2). However, the effect on the dispersibility of the copper compound and the halogen compound is insufficient, and mechanical properties are impaired by copper precipitates and aggregates, etc., and it is possible to obtain a polyamide resin composition having sufficiently satisfied heat aging properties. I could not do it.
JP 50-148461 A JP 2004-211083 A

  The present invention greatly improves the heat aging resistance of the polyamide resin, and suppresses metal copper precipitation in the extruder or molding machine, in addition to excellent processing stability, without reducing the mechanical properties of the product. Another object of the present invention is to provide a polyamide master batch pellet or a molded product using the same, which can be produced more efficiently because the appearance color change of the obtained molded product due to water absorption is extremely small.

  As a result of intensive studies in order to solve the above problems, the present inventors have determined that the compounding ratio of copper and halogen is within a specific range, such as a copper compound, an alkali halide, and a higher fatty acid metal having a specific range of oxidation. Polyamide master batch pellets obtained by blending at least one higher fatty acid compound selected from a salt, a higher fatty acid ester and a higher fatty acid amide to produce a granulated product, and melt-kneading the granulated product with a polyamide resin Thus, the inventors have found that the above-mentioned problem can be specifically solved, and have made the present invention.

That is, the present invention
(1) At least one compound selected from a copper compound (a), an alkali halide (b), a higher fatty acid metal salt having an acid value in the range of 0.01 to 500 mg / g, a higher fatty acid ester, and a higher fatty acid amide ( c) a polyamide masterbatch pellet obtained by melt-kneading the granulated product (A) and the polyamide resin (B), wherein the molar ratio of halogen atoms to copper atoms contained in the polyamide masterbatch (halogen atoms / Polyamide masterbatch pellets, wherein the copper atom) is 5 to 40, and the copper concentration in the masterbatch is 1 ppm to 10% by weight,
(2) The polyamide masterbatch pellet according to (1) above, wherein the alkali halide (b) has an average particle size of 200 μm or less,
(3) The above (1) or (3), wherein the compound (c) is a salt of a higher fatty acid and at least one metal selected from Group I, Group II metal, Cu, Zn, Al of the periodic table Polyamide masterbatch pellets according to (2),
(4) The polyamide master batch pellet according to any one of (1) to (3) above, wherein the concentration of the compound (c) in the granulated product (A) is 2 to 50% by weight,
(5) The polyamide masterbatch pellets 99.9 to 0.1% by weight described in any one of the above (1) to (4) are mixed with polyamide resin pellets 0.1 to 99.9% by weight and molded. A polyamide resin molded product characterized by being obtained,
It is.

  The polyamide masterbatch pellet containing the copper compound and halogen compound prepared by the method of the present invention is considered to have improved dispersibility compared with the masterbatch of the conventional method, and has a specific high heat aging property and high appearance. Have Surprisingly, a molded product excellent in high heat aging resistance and appearance can be obtained as compared with the method of adding a copper compound and a halogen compound in the polymerization step. Moreover, it has the effect of significantly reducing copper deposition during processing. According to the method of the present invention, the addition of the copper compound and the halogen compound to the polyamide resin is carried out by a masterbatch method with high production efficiency, and the product has a high heat aging resistance and a high appearance equal to or higher than those in the polymerization process. It became possible to get.

The present invention will be specifically described below.
Hereinafter, the contents of the present invention will be described in detail. The polyamide resin (B) used in the present invention is not particularly limited as long as it is a known polyamide resin, and may be any of homopolyamide, copolymerized polyamide, and blended polyamide. May be. As representative examples, lactams such as ε-caprolactam, enantolactam, ω-laurolactam, aminocarboxylic acids such as ε-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, tetramethylenediamine, hexamethylenediamine, Undecamethylenediamine, dodecamethylenediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, m-xylylenediamine, p-xylylenediamine, 1,3- Diamines such as bisaminomethylcyclohexane, 1,4-bisaminomethylcyclohexane, bis (4-aminocyclohexyl) methane, bis (p-aminocyclohexyl) propane, isophoronediamine, adipic acid, suberic acid, azelaic acid, sebacic acid, Dodecane Carboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, polyamides obtained from dicarboxylic acids such as dimer acid.

  Specific examples include homopolymers such as Ny6, Ny11, Ny12, Ny66, Ny46, Ny610, Ny612, Ny6I, Ny66 / 6 (/ indicates a copolymer), Ny66 / 610, Ny66 / 612, Ny66 / 6I, Copolymers such as Ny66 / 6T, Ny66 / 6T / 6I, Ny66 / 6T / 612, Ny6T / 6I, Ny6T / 6I / 612, Ny6T / 6, Ny66‖Ny6 (‖ indicates a blend), Ny66 / 6I There are blend polymers such as ‖Ny6, Ny66 / 6T‖Ny66, Ny66 / 6T‖Ny6, Ny66 / 6‖Ny6. The polyamide used in the present invention is obtained by a known polymerization technique, and may be any of melt polymerization, solid phase polymerization, solution polymerization, interfacial polymerization, etc. The molecular weight of the polymer is not limited and has a known molecular weight range. Can be used.

As the copper compound (a) used in the present invention, copper halide, copper acetate, copper propionate, copper benzoate, copper adipate, copper terephthalate, copper isophthalate, copper salicylate, copper nicotinate, copper stearate Or a copper complex salt coordinated to a chelating agent such as ethylenediamine (en) or ethylenediaminetetraacetic acid. These copper compounds may be used independently and may mix 2 or more types. Among these, preferable examples include copper iodide, cuprous bromide, cupric bromide, cuprous chloride, and copper acetate.
The amount of the copper compound added is 1 ppm to 10% by weight in terms of the copper concentration in the master batch. When the copper concentration is 1 ppm or more, a sufficient heat resistance effect is obtained, and if the copper concentration is 10% by weight or less, sufficient improvement in heat aging resistance can be obtained, and copper precipitation and discoloration of the molded product can be achieved. Can be suppressed. The copper concentration in the master batch is preferably 10 ppm to 5% by weight, and more preferably 20 ppm to 1% by weight.

  Examples of the alkali halide (b) used in the present invention include potassium iodide, sodium iodide, potassium bromide, potassium chloride, sodium chloride and the like. The molar ratio (halogen atom / copper atom) of halogen atoms and copper atoms contained in the polyamide master batch is 5 to 40, preferably 11 to 30. When the molar ratio of the halogen atom to the copper atom is 5 or more, it is preferable because copper deposition and discoloration of the molded product can be suppressed. If the molar ratio of the halogen atom and the copper atom is 40 or less, a sufficient improvement effect can be obtained, and the problem of corroding the screw of the molding machine can be suppressed. Moreover, the molar ratio (halogen atom / copper atom) of the halogen atom and the copper atom contained in the granulated product (A) is 5 to 40, preferably 11 to 40. When the molar ratio of the halogen atom and the copper atom is 5 or more, the precipitation of copper and the discoloration of the polyamide master batch pellet can be suppressed when the granulated product (A) and the polyamide resin (B) are melt-kneaded. If the molar ratio of the halogen atom and the copper atom is 40 or less, a sufficient improvement effect can be obtained, and problems such as corrosion of the apparatus for melting and kneading the granulated product (A) and the polyamide resin (B) can be suppressed. . When the granulated product (A) and the polyamide resin (B) are melt-kneaded, the molar ratio of halogen atoms and copper atoms in the polyamide master batch can be adjusted by additionally preparing an alkali halide or a copper compound. .

  Moreover, it is preferable that the average particle diameter of the alkali halide before forming a granulated material is 200 micrometers or less. When it is 200 μm or less, the alkali halide can be sufficiently dispersed when the granulated product (A) and the polyamide resin (B) are melt-kneaded, and the effect of preventing copper precipitation is sufficient. A decrease in mechanical properties can be suppressed. The average particle size of the alkali halide is preferably 150 μm or less, and more preferably 100 μm or less.

  The compound (c) used by this invention is illustrated below. Higher fatty acid metal salts include lithium stearate, aluminum monostearate, aluminum distearate, aluminum tristearate, calcium stearate, zinc stearate, sodium montanate, calcium montanate, lithium montanate, zinc montanate, etc. , Lithium stearate, aluminum monostearate, aluminum distearate, aluminum tristearate, sodium montanate, calcium montanate, lithium montanate, zinc montanate, the effect of inhibiting corrosion of equipment during melt-kneading and molding Is high and preferable. Examples of higher fatty acid esters include stearyl stearate, montanic acid 1,3 butanediol ester and partially saponified products thereof, behenyl behenate, fatty acid ester of neoventyl polyol, trimethylolpropane trilaurate, octyl stearate, butyl stearate Examples thereof include rate, montanic acid diethanolamine ester, montanic acid glycerin ester, montanic acid polyol ester, and trimethylolpropane montanic acid ester. Higher fatty acid amides include stearic acid amide, behenic acid amide, oleic acid amide, erucic acid amide, palmitic acid amide, behenic acid and stearyl amide monoamide, methylene bis stearic acid amide, ethylene bis stearic acid amide, N-stearyl elca Examples include acid amides, N-oleyl palmitic acid amides, ethylene bisoleic acid amides, ethylene biserucic acid amides, p-phenylene bis stearic acid amides, and xylylene bisstearyl ureas. These compounds (c) may be used alone or in combination of two or more. These compounds (c) having an acid value of 0.01 to 500 mg / g are preferred because alkali halides can be prevented from agglomerating and solidifying during processing. The acid value of the compound (c) is preferably 0.01 to 350 mg / g, and more preferably 0.01 to 150 mg / g.

When the compound (c) is selected from higher fatty acid metal salts, it is preferable to use at least one metal salt selected from higher fatty acids and Group I, Group II metals, Cu, Zn, and Al of the periodic table. Thus, the effect of the present invention can be further enhanced. It is more preferable to use at least one metal salt selected from higher fatty acids and Group I, Group II metals, Cu, and Al of the periodic table.
The content of the compound (c) in the granulated product (A) is preferably 2 to 50% by weight. If the content of the compound (c) is 2% by weight or more, not only the effect of preventing the precipitation of copper is great, but also the copper compound (a) and the compound (a) during melt kneading of the granulated product (A) and the polyamide resin (B) Alkali halides can be sufficiently dispersed and deterioration of mechanical properties can be suppressed. If content of a compound (c) is 50 weight% or less, the effect of copper precipitation prevention can be expected. The content of the compound (c) in the granulated product (A) is more preferably 2 to 30% by weight.

  In the present invention, the granulated product (A) of the copper compound (a), the alkali halide (b), and the compound (c) is obtained by a known granulation technique, and is a compression granulation method, a tableting method, a dry method. Any of extrusion granulation method, melt extrusion granulation method and the like may be used. Furthermore, a molded object can be grind | pulverized and it can also adjust to a desired particle size. The pulverization method at this time is also a known pulverization technique, and may be any one of a hammer mill, a knife mill, a ball mill, a jaw crusher, a cone crusher, a roller mill, a jet mill, and a milling tool. The specific gravity of the obtained granulated product is preferably in the range of 0.3 to 1.0 g / cc, more preferably 0.5 to 0.8 g / cc. When the specific gravity is 0.3 g / cc or more, the generation of fine powder due to pulverization during the handling of the granulated product is suppressed and the handling is easy, and the dispersion after melt-kneading due to the classification of the fine powder can be suppressed. In addition, if the specific gravity is 1.0 g / cc or less, the granulated product is completely crushed during melt-kneading and becomes uniform in the polyamide resin, and the mechanical properties may deteriorate due to the aggregate remaining in the resin. Absent.

The granulated product (A) and the polyamide resin (B) can be mixed before melt kneading, or can be fed separately from the polyamide resin (B) when melt kneading. When mixing before melt-kneading, it is not particularly limited as long as it is a known mixing apparatus, and examples thereof include a tumbler, Henschel, Proshear mixer, Nauter mixer, flow jet mixer and the like.
The apparatus for melt kneading the granulated product (A) and the polyamide resin (B) is not particularly limited as long as it is a known technique. For example, melt kneaders such as single-screw or twin-screw extruders, Banbury mixers, and mixing rolls are preferably used.

  The polyamide masterbatch pellets of the present invention can be used by mixing with other polyamide resins. If the mixing ratio is 99.9 to 0.1% by weight of the polyamide masterbatch pellets of the present invention and 0.1 to 99.9% by weight of other polyamide resin pellets are mixed and formed, copper may precipitate during the molding. In addition, a molded product having excellent heat aging resistance and little discoloration can be obtained without causing corrosion of the screw of the molding machine. It is preferable that other polyamide resin pellets are 30 to 99.8% by weight with respect to 70 to 0.2% by weight of the polyamide masterbatch pellets, and other polyamide resin pellets 50 with respect to 50 to 0.5% by weight of the polyamide masterbatch pellets. More preferably, it is made into 99.5 weight%.

The present invention will be described based on examples. In Examples and Comparative Examples, long-term heat aging resistance, copper deposition rate, and color tone change of molded products were measured by the following methods.
(1) Long-term heat aging property A test piece obtained under the following molding conditions was treated in a hot air oven at 180 ° C. for a predetermined time, and then the tensile strength was measured according to ASTM-D638. And the tensile strength after heat processing with respect to the tensile strength measured before heat processing was computed as tensile strength retention. The heat treatment time at which the tensile strength retention was 50% was defined as the half life.

(2) Change in color tone The test piece obtained under the following molding conditions was immersed in water at 23 ° C for 240 hours, and the color tone of the test piece after immersion was measured with a color difference meter (ND-K6B type manufactured by Nippon Denshoku Co., Ltd.). did. The measurement conditions are as follows.
Measurement items: L (lightness), a (redness), b (yellowness), ΔE (color difference)
Calculation: ΔE = √ {(L _S −L _B ) ² + (a _S −a _B ) ² + (b _S −b _B ) ² }
a _S , b _S , L _S a, b, L before water absorption treatment
a _B , b _B , L _B a, b, L before water absorption treatment
The color difference (ΔE) from the color tone of the molded product before water absorption was defined as the color tone change.

(Molding condition)
Injection molding machine: Nissei Plastic PS-40e
Mold: ASTM-D638 test piece mold Cylinder temperature: 280 ° C Flat mold temperature: 80 ° C
Plasticization stroke: 63 mm
Screw rotation speed: 200rpm
Injection time: 10 seconds Cooling time: 15 seconds

[Example 1]
A known melt polymerization was performed using an equimolar aqueous solution (50% by weight concentration) of hexamethylenediamine and adipic acid to obtain a pellet-like polyamide 66 resin. After stirring and mixing potassium iodide: 85% by weight, copper iodide: 5% by weight, and calcium montanate: 10% by weight, a granulated granule was prepared. Pellets of polyamide 66 resin: 70% by weight and granulated granules of potassium iodide / copper iodide / calcium montanate: 30% by weight were mixed in a tumbler-type blender. The obtained mixture was melt-kneaded with a twin-screw extruder to obtain polyamide master batch pellets. The polyamide masterbatch pellets: 2% by weight and polyamide 66 resin: 98% by weight were mixed in a tumbler type blender, and the mixture was melt-kneaded in a twin screw extruder to obtain copper-containing polyamide 66 resin pellets. An ASTM-D638 test piece was molded from the obtained copper-containing polyamide 66 resin pellets. Long-term heat aging properties and color tone changes were measured, and the physical properties shown in Table 1 were obtained.

[Example 2]
An ASTM-D638 test piece was prepared in the same manner as in Example 1 except that potassium iodide pulverized to an average particle size of 20 μm in advance by a jet mill was used, and the results of measuring long-term heat aging resistance and color tone change were measured. It described according to Table 1.

[Comparative Example 1]
When preparing the polyamide master batch pellet, the pelletized polyamide 66 resin obtained by melt polymerization was previously refined and average particle diameter: 20 μm potassium iodide: 25.5 wt%, copper iodide: 1.5 An ASTM-D638 test piece was molded in the same manner as in Example 1 except for mixing wt% and calcium montanate: 3.0 wt% and melt kneading using a twin screw extruder. The results of measuring long-term heat aging resistance and color tone change are shown in Table 1.

[Comparative Example 2]
When the polyamide 66 resin is melt polymerized, potassium iodide: 41.0% by weight and copper iodide: 12.0% by weight with respect to an equimolar aqueous salt solution (50% by weight concentration) of hexamethylenediamine and adipic acid as raw materials Aqueous solution containing: 0.25 wt% was blended, and known melt polymerization was performed to obtain a pellet-like polyamide 66 resin. Only the obtained polymer was melt-kneaded with a twin-screw extruder in the same manner as in Example 1 to obtain copper-containing polyamide 66 resin pellets. An ASTM-D638 test piece was molded from the obtained copper-containing polyamide 66 resin pellets. The results of measuring long-term heat aging resistance and color tone change are shown in Table 1.

[Comparative Example 3]
Using only polyamide 66, melt-kneading was carried out in a twin-screw extruder in the same manner as in Example 1, and an ASTM-D638 test piece was molded from the obtained polyamide 66 resin pellet containing no copper. The results of measuring long-term heat aging resistance and color tone change are shown in Table 1.

  The polyamide masterbatch pellet of the present invention can be suitably used in the field of polyamide resins used for heat-resistant applications.

Claims (5)

  From at least one compound (c) selected from a copper compound (a), an alkali halide (b), a higher fatty acid metal salt having an acid value in the range of 0.01 to 500 mg / g, a higher fatty acid ester, and a higher fatty acid amide And a polyamide master batch pellet obtained by melt-kneading the granulated product (A) and the polyamide resin (B), and the molar ratio of halogen atoms to copper atoms (halogen atoms / copper atoms) contained in the polyamide master batch Is a polyamide masterbatch pellet, wherein the masterbatch has a copper concentration of 1 ppm to 10% by weight.   The polyamide masterbatch pellet according to claim 1, wherein the average particle diameter of the alkali halide (b) powder is 200 µm or less.   The compound (c) is a salt of a higher fatty acid and at least one metal selected from Group I, Group II metal, Cu, Zn, and Al of the periodic table. Polyamide master batch pellet.   The polyamide master batch pellet according to any one of claims 1 to 3, wherein the concentration of the compound (c) in the granulated product (A) is 2 to 50% by weight.   It is obtained by mixing 99.9 to 0.1% by weight of polyamide masterbatch pellets according to any one of claims 1 to 4 with 0.1 to 99.9% by weight of polyamide resin pellets and molding. Polyamide resin molded product.