JP6008616B2 - Polyamide resin composition - Google Patents

Description

  The present invention relates to a polyamide resin composition.

  Polyamides typified by polyamide 66 and polyamide 6 are excellent in molding processability, mechanical properties, and chemical resistance, so they are used in automobiles, electric and electronic, industrial materials, industrial materials, daily use, and home use. Widely used as a material for various parts.

  It is well known that a polyamide resin is compounded with carbon black for the purpose of imparting weather resistance, product color, etc. to a polyamide resin. However, when carbon black is blended, the objectives of improving the weather resistance of polyamide resin molded products and the color of the products are generally achieved, but the elongation rapidly decreases compared to the polyamide resin molded products before coloring, and the molded product shape Depending on the case, there is a drawback that it is easy to break or crack during use.

  In order to solve this problem, proposals have been made to use a special dye in combination with carbon black (for example, see Patent Document 1) and proposals to use a higher fatty acid amide as a dispersant (for example, see Patent Document 2). .

Japanese Patent Publication No. 60-43379 JP-A-61-55146

  However, although the polyamide resin composition described in Patent Document 1 certainly shows an improvement in elongation, since it uses a dye, not only the weather resistance is deteriorated, but the surface of the molded product is used in the atmosphere. Depending on the bottom, there is a problem that it becomes cloudy or other molded products that are in contact with it are colored.

  Further, the polyamide resin composition described in Patent Document 2 has not been sufficiently realized to the extent that toughness is expected.

  Therefore, the problem to be solved by the present invention is that without using a dye that the weather resistance deteriorates, the surface of the molded product becomes cloudy during use, and other molded products that are in contact with the product are colored. An object of the present invention is to provide a polyamide resin composition having excellent toughness.

  As a result of studying carbon black to be blended with polyamide resin, it was found that even if the polyamide resin is colored with carbon black, a carbon black having a specific average primary particle size gives a resin composition with excellent toughness. Completed the invention.

That is, the present invention relates to the following.
[1]
Containing a polyamide resin (A) and carbon black (B),
The content of carbon black (B) is 0.05 to 5 parts by weight with respect to 100 parts by weight of the polyamide resin (A),
The resin composition whose average primary particle diameter of carbon black (B) is 35 nm-80 nm.
[2]
The resin composition according to [1], wherein the polyamide resin (A) includes polyamide 66.
[3]
The resin composition according to [1] or [2], wherein the polyamide resin (A) is composed of polyamide 66 / polyamide 6 = 100/0 to 100/5 (weight ratio).
[4]
[1] A resin composition for a binding band comprising the resin composition according to any one of [3].

  According to the present invention, it is possible to obtain a black colored polyamide resin composition having excellent toughness and little deterioration in physical properties even under an outdoor exposure environment, and a molded product thereof.

  Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. In addition, this invention is not restrict | limited to the following embodiment, A various deformation | transformation can be implemented within the range of the summary.

≪Resin composition≫
The resin composition of the present embodiment (hereinafter also referred to as “polyamide resin composition”) is:
Containing a polyamide resin (A) and carbon black (B),
The content of carbon black (B) is 0.05 to 5 parts by weight with respect to 100 parts by weight of the polyamide resin (A),
The average primary particle diameter of carbon black (B) is 35 nm to 80 nm.

<Polyamide resin (A)>
The polyamide resin (A) used in the present embodiment is not particularly limited. For example, polycaprolactam (polyamide 6), polytetramethylene adipamide (polyamide 46), polyhexamethylene adipamide (polyamide 66), poly Hexamethylene sebacamide (polyamide 610), polyhexamethylene dodecamide (polyamide 612), polyundecamethylene adipamide (polyamide 116), polyundecalactam (polyamide 11), polydodecalactam (polyamide 12), poly Trimethylhexamethylene terephthalamide (polyamide TMHT), polyhexamethylene isophthalamide (polyamide 6I), polynonanemethylene terephthalamide (9T), polyhexamethylene terephthalamide (6T), polybis (4-amino) Cyclohexyl) methane dodecamide (polyamide PACM12), polybis (3-methyl-aminocyclohexyl) methane dodecamide (polyamide dimethyl PACM12), polymetaxylylene adipamide (polyamide MXD6), polyundecamethylene hexahydroterephthalamide (polyamide 11T) (H)), and polyamide copolymers containing at least two different polyamide components among these, or mixtures thereof.

  The polyamide resin (A) used in the present embodiment preferably contains polyamide 66, and more preferably comprises polyamide 66 / polyamide 6 = 100/0 to 100/5 (weight ratio).

(Polyamide 66)
As the polyamide 66, for example, a polyamide 66 made of a hexamethylene unit having an amide bond (—NHCO—) and an adipic acid unit in the main chain and obtained by polymerizing these unit raw materials can be mentioned. The relative viscosity of polyamide 66 is a value measured at 25 ° C. in 98% sulfuric acid at a concentration of 1% in accordance with JIS K6810, and is preferably in the range of 1.5 to 3.0.

(Polyamide 6)
Examples of the polyamide 6 include polyamide 6 obtained by using ε-caprolactam having an amide bond (—NHCO—) in the main chain as a raw material and ring-opening polymerization of the raw material. The relative viscosity of the polyamide 6 is a value measured at a concentration of 1% in 98% sulfuric acid and a temperature of 25 ° C. according to JIS K6810, and is preferably 1.5 to 3.0.

<Carbon black (B)>
Carbon black (B) used in this embodiment is carbon black having an average primary particle size of 35 to 80 nm. The average primary particle diameter of carbon black (B) is preferably 70 to 80 nm. By using carbon black (B) having an average primary particle size within the above range, a polyamide resin composition having excellent toughness and weather resistance can be obtained.

  As a method for obtaining carbon black (B) having an average primary particle diameter within the above range, any method of oil furnace method, gas furnace method, channel method or thermal method can be used, and it is not particularly limited.

  Carbon black (B) has a dibutyl phthalate (hereinafter also referred to as “DBP”) oil absorption of preferably 60 to 150 ml / 100 g, and more preferably 70 to 90 ml / 100 g.

  The resin composition using carbon black (B) having an average primary particle diameter within the above range and a DBP oil absorption within the above range has a small change in color tone when exposed to sunlight, and the surface of the molded product Roughness tends to be suppressed.

  In the present embodiment, the average primary particle diameter of carbon black (B) is a value measured by the following method. An aggregate enlarged image is obtained by the procedure described in the ASTM D3849 standard (standard test method of carbon black-morphological characterization by electron microscopy), and 3,000 particle sizes as unit constituent particles are obtained from the aggregate image. Measure and determine the average of the measured values to obtain the average primary particle size. The DBP oil absorption of carbon black (B) is a value obtained by measurement according to JIS K6217 standard.

  In the polyamide resin composition of the present embodiment, the content of carbon black (B) is 0.05 to 5 parts by weight with respect to 100 parts by weight of the polyamide resin (A), and 0.15 to 0.5 parts by weight. It is preferable that it is 0.2-0.3 weight part. When the content of the carbon black (B) is within the above range, the polyamide resin composition is excellent in toughness and decreases in physical properties even under an outdoor exposure environment.

<Other additives>
In the polyamide resin composition of the present embodiment, other additives, for example, stabilizers such as crystal nucleating agents, heat-resistant agents and ultraviolet absorbers, flame retardants, charging, etc., as long as they do not impair the purpose of the present invention. Inhibitors, plasticizers, lubricants, and the like can also be added.

  As the heat-resistant agent used in the polyamide resin composition of the present embodiment, for example, a copper compound and a halogen compound (excluding copper halide) are preferably used in order to improve long-term heat resistance. Specific examples of the copper compound include cuprous chloride, cupric chloride, cupric bromide, cuprous iodide, cupric iodide, cupric sulfate, cupric nitrate, and phosphoric acid. Copper, cuprous acetate, cupric acetate, cupric salicylate, cupric stearate, cupric benzoate and copper such as inorganic copper halide and xylylenediamine, 2-mercaptobenzimidazole, benzimidazole Compound etc. are mentioned. Among these, preferred examples of the copper compound include copper iodide, cuprous bromide, cupric bromide, cuprous chloride, and copper acetate. Specific examples of the halogen compound (excluding copper halide) include potassium iodide, sodium iodide, potassium bromide, potassium chloride, sodium chloride and the like. Of these, potassium iodide is more preferably used. The compounding amount of the heat-resistant agent such as a copper compound and a halogen compound other than the halogen copper is 0.05 to 0.75 weight with respect to 100 parts by weight of the polyamide resin composition in order to have good mold contamination and toughness. Part is more preferable, and 0.05 to 0.5 part by weight is more preferable.

  Examples of the crystal nucleating agent used in the polyamide resin composition of the present embodiment include talc, silica, kaolin and the like.

  Examples of the plasticizer used in the polyamide resin composition of the present embodiment include octyl p-oxybenzoate and N-butylbenzenesulfonamide.

  Antistatic agents used in the polyamide resin composition of the present embodiment include alkyl sulfate type anionic antistatic agents, nonionic antistatic agents such as polyoxyethylene sorbitan monostearate, betaine amphoteric antistatic agents, etc. Is mentioned.

  Examples of the flame retardant used in the polyamide resin composition of the present embodiment include red phosphorus, melamine cyanurate, magnesium hydroxide, aluminum hydroxide and other hydroxides, ammonium polyphosphate, brominated polystyrene, brominated polyphenylene ether, bromine. And a combination of a brominated flame retardant and antimony trioxide.

  The addition amount of these additives is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and further preferably 3 parts by mass or less with respect to 100 parts by mass of the polyamide resin composition.

  Moreover, in the polyamide resin composition of this embodiment, it is also preferable to mix | blend a mold release agent and a lubricant in order to improve the mold release property at the time of shaping | molding. Examples of release agents and lubricants include long-chain aliphatic carboxylic acids having 14 or more carbon atoms such as stearic acid and palmitic acid and derivatives thereof (for example, esters, alkali metal salts, alkaline earth metal salts, amides, etc.) ), Higher aliphatic alcohols having 14 or more carbon atoms such as stearyl alcohol and derivatives thereof, amines and derivatives thereof having 14 or more carbon atoms such as stearylamine, waxes such as low molecular weight polyethylene wax, paraffin wax, silicone oil And silicone gum. Among these, an aliphatic carboxylic acid derivative is preferable. Examples of the aliphatic carboxylic acid derivatives include aliphatic carboxylic acid esters, aliphatic carboxylic acid metal salts (alkali metal salts and alkaline earth metal salts), and aliphatic carboxylic acid amides.

  Examples of the aliphatic carboxylic acid esters include esters of long-chain aliphatic carboxylic acids having 14 or more carbon atoms such as palmitic acid, stearic acid, and montanic acid.

  Examples of the aliphatic carboxylic acid metal salt include alkali metal salts and alkaline earth metal salts of long-chain aliphatic carboxylic acids having 14 or more carbon atoms. Specific examples thereof include calcium stearate and calcium montanate. , Sodium montanate, zinc stearate, aluminum stearate, sodium stearate, lithium stearate and the like.

  The compounding amount of the release agent and the lubricant is preferably 0.02 to 0.5 parts by weight, more preferably 0.03 to 0.3 parts by weight with respect to 100 parts by weight of the polyamide resin composition. . When the blending amount of the release agent and the lubricant is equal to or more than the lower limit value, the release property is good, and the release tends to be performed without taking a long cooling time. This leads to shortening of the molding time cycle, that is, improvement of productivity. Moreover, discoloration of a polyamide resin composition can be suppressed as the compounding quantity of a mold release agent is below the said upper limit.

≪Method for producing resin composition≫
The polyamide resin composition of the present embodiment can be produced according to a conventional method for producing a resin composition. For example, the polyamide resin (A), carbon black (B) and other various additives contained as necessary are well mixed in a mixing apparatus such as a tumbler mixer, a Henschel mixer, a ribbon blender, and the resulting mixture. For example, there is a method of supplying a resin composition pellet by supplying it to a melt-kneader such as a vented single-screw or twin-screw extruder or a Banbury mixer and melt-kneading. In addition, after preparing a carbon black masterbatch in which carbon black (B) is melt-kneaded in part or all of the polyamide resin (A) in advance, the remaining components are melt-kneaded or dry blended into the masterbatch to obtain a resin composition The method of obtaining a thing is also mentioned. Moreover, the method of pellet-blending two or more types of melt-kneaded materials having different compositions to obtain a resin composition may be used.

  In the present embodiment, a carbon black masterbatch obtained by melt-kneading carbon black (B) in part of the polyamide resin (A) is manufactured in advance, and then the remaining polyamide resin (A) and necessary A method of obtaining a resin composition by melting and kneading other components contained therein is preferable. By adopting such a method, in the resulting resin composition, the dispersibility of the carbon black (B) is further improved, and the weather resistance tends to be further improved.

≪Usage≫
The resin composition of the present embodiment can be molded into a molded product by a known method. There is no restriction | limiting also about the molding method, For example, injection molding, injection compression molding, extrusion molding, blow molding, press molding, etc. are mentioned. Among these, it is preferable to employ an injection molding method from the viewpoint of fluidity.
The resin composition of this embodiment can be suitably used as a resin composition for a binding band.

  Examples The present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. The materials and evaluation methods used in the examples are shown below.

[Polyamide resin]
Polyamide 6: Ube Industries, Ltd. product name 1013A
Polyamide 66-1: Product name Leona 1300 manufactured by Asahi Kasei Chemicals Corporation
Polyamide 66-2: Product name Leona 1402S manufactured by Asahi Kasei Chemicals Corporation
The tensile fracture elongation of polyamide 66 was measured in the same manner as the method for measuring the properties of the polyamide resin composition described later.

〔Carbon black〕
Carbon Black-1; “BLACK PEARLS 130” manufactured by Cabot Japan, average primary particle size 75 nm, DBP oil absorption 70 ml / 100 g
Carbon black-2; “# 10B” manufactured by Mitsubishi Chemical Corporation, average primary particle size 75 nm, DBP oil absorption 84 ml / 100 g
Carbon Black-3; “BLACK PEARLS 880” manufactured by Cabot Japan, average primary particle diameter 16 nm, DBP oil absorption 105 ml / 100 g
Carbon black-4; “VULCAN9A32” manufactured by Cabot Japan, average primary particle size 19 nm, DBP oil absorption 114 ml / 100 g
Carbon Black-5; “# 52” manufactured by Mitsubishi Chemical Corporation, average primary particle size 27 nm, DBP oil absorption 60 ml / 100 g

  In this example, the average primary particle size was measured by the following method. An aggregate enlarged image is obtained by the procedure described in the ASTM D3849 standard (standard test method of carbon black-morphological characterization by electron microscopy), and 3,000 particle sizes as unit constituent particles are obtained from the aggregate image. Measured and averaged to obtain the average primary particle size. Further, the DBP oil absorption of carbon black was measured according to JIS K6217 standard.

〔Master Badge〕
Master batch-1; a composition obtained by melt-kneading polyamide 6 and carbon black-1 at a ratio of polyamide 6 / carbon black-1 = 90/10 (weight ratio). Master batch-2; A composition obtained by melt-kneading carbon black-2 at a ratio of polyamide 6 / carbon black-1 = 90/10 (weight ratio) Masterbatch-3; Polyamide 66-1 and carbon black-1 Polyamide 66-1 / carbon black-1 = 90/10 (weight ratio) obtained by melt-kneading composition Masterbatch-4; Polyamide 66-1 and carbon black-2 were mixed with polyamide 66- Composition obtained by melt-kneading at a ratio of 1 / carbon black-1 = 90/10 (weight ratio) Masterbatch-5; Polyamide 6 and carbon A composition obtained by melt-kneading N-black-3 at a ratio of polyamide 6 / carbon black-1 = 90/10 (weight ratio), master batch-6; polyamide 6 and carbon black-4, polyamide 6 / carbon black-1 = 90/10 (weight ratio) obtained by melt-kneading at a ratio of master batch-7; polyamide 6 and carbon black-5, polyamide 6 / carbon black-1 = 97 Composition obtained by melt-kneading at a ratio of / 3 (weight ratio) Masterbatch-8; manufactured by Asahi Kasei Chemicals Co., Ltd. Product name LCA20 A33555M (dye-based masterbatch)

[Examples 1-4 and Comparative Examples 1-2]
Polyamide 66-2 and each master batch 1-6 were weighed so that polyamide 66-2 / master batch = 97/3 (weight ratio) and pellet blended to obtain polyamide resin composition pellets. Moreover, the characteristic of the obtained polyamide resin composition was measured by the method of the below-mentioned. The measurement results are shown in Tables 1 and 2.

[Comparative Examples 3 to 4]
Polyamide 66-2 and each master batch 7-8 were weighed so that polyamide 66-2 / master batch = 95/5 (weight ratio) and pellet blended to obtain polyamide resin composition pellets. Moreover, the characteristic of the obtained polyamide resin composition was measured by the method of the below-mentioned. The measurement results are shown in Table 2.

≪Measurement method of characteristics of polyamide resin composition≫
<Creation of specimen>
Using a pellet of the polyamide resin composition obtained by the above method, a dumbbell test piece (2 mm thickness) for ISO tensile test was placed at a cylinder temperature of 280 ° C. and gold using an injection molding machine (SE50D manufactured by Sumitomo Heavy Industries, Ltd.). Molding was performed at a mold temperature of 80 ° C., an injection speed of 40 mm / sec, a screw rotation speed of 120 rpm, and a cooling time of 10 sec.

<Evaluation of toughness and weather resistance>
About the test piece obtained above, the tensile fracture elongation before and after the exposure using a sunshine weather meter (Suga Test Instruments WEL-SUW-DC) was measured according to ISO-527 as follows. Moreover, based on this measured value etc., toughness and weather resistance were evaluated in the following three stages, respectively.

[Exposure method]
Equipment used: Sunshine weather meter (Suga Test Instruments WEL-SUW-DC)
Black panel temperature: 63 ° C
Water injection time: 18 minutes Water injection stop time: 102 minutes Exposure time: 2000 hr

[Tensile test method]
Equipment used: Instron universal testing machine (Instron 50KN)
Tensile speed: 50 mm / sec
Test temperature: 23 ° C

[Toughness]
○: Tensile fracture elongation before exposure is equal to or greater than tensile fracture elongation of polyamide 66 (Leona 1402S) before coloring Δ: Tensile fracture elongation before exposure is 50% of tensile fracture elongation of polyamide 66 (Leona 1402S) before coloring More than less than 100% ×: tensile fracture elongation before exposure is less than 50% of tensile fracture elongation of polyamide 66 (Leona 1402S) before coloring

[Weatherability]
○: Tensile fracture elongation after 2000 hr exposure is 80% or more of the tensile fracture elongation before exposure Δ: Tensile fracture elongation after 2000 hr exposure is 50% or more and less than 80% of the tensile fracture elongation before exposure ×: After 2000 hr exposure Less than 50% of the tensile fracture elongation before exposure

Claims (4)

Containing a polyamide resin (A) and carbon black (B),
The content of carbon black (B) is 0.05 to 5 parts by weight with respect to 100 parts by weight of the polyamide resin (A),
The resin composition whose average primary particle diameter of carbon black (B) is 70 nm-80 nm.   The resin composition according to claim 1, wherein the polyamide resin (A) comprises polyamide 66.   The resin composition according to claim 1 or 2, wherein the polyamide resin (A) is composed of polyamide 66 / polyamide 6 = 100/0 to 100/5 (weight ratio). The resin composition for binding bands which consists of a resin composition as described in any one of Claims 1-3.