JP2003171549A - Polyamide resin composition excellent in weathering resistance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyamide resin composition which exhibits a sufficient weathering resistance under outdoor exposure or exposure to ultraviolet rays even when the composition contains a pigment containing a metal component (e.g. titanium oxide) or a remaining catalyst containing a metal ingredient and which is suitable for parts of automobiles, railway exteriors, parts for building materials and housing equipments, etc., and for parts of lighting equipments, etc. <P>SOLUTION: This resin composition of 100 pts.wt. contains an N-O-R type low-molecular-weight hindered amine light stabilizer and a high-molecular-weight hindered amine light stabilizer in an amount of 0.05-2 pts.wt. <P>COPYRIGHT: (C)2003,JPO

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 which is excellent in weather resistance under outdoor exposure or ultraviolet exposure environment and is suitable for parts of automobiles, railroad exteriors, building materials and housings, parts such as lighting equipments. It is about.

[0002]

2. Description of the Related Art Polyamide resins are widely used in automobile parts, electronic / electrical parts, mechanical parts, building materials / housing related parts, etc. due to their excellent mechanical properties, molding processability and chemical resistance. Has been done. However, the polyamide resin is extremely susceptible to oxidative deterioration, and unfavorable phenomena such as deterioration of mechanical strength, generation of cracks on the surface, and coloring occur as the degree of polymerization decreases. In particular, this oxidative deterioration is accelerated by heat and light, and its use is restricted in outdoor exposure.

For the purpose of preventing these deterioration phenomena, it is known to add various stabilizers to polyamide resin.
It is disclosed in Japanese Patent Laid-Open No. 93652 and Japanese Patent Laid-Open No. 2-229853. However, these weather resistance improving effects were not sufficiently satisfactory.

On the other hand, Japanese Examined Patent Publication No. 7-103330 discloses a specific polyamide with a hindered phenol heat-resistant agent,
A polyamide resin composition has been proposed in which a triazole-based UV absorber and a hindered amine-based light stabilizer are blended to improve weather resistance. Japanese Unexamined Patent Publication (Kokai) No. 5-93134 proposes a weather resistant composition in which a specific polyamide is blended with a triazole-based UV absorber, a hindered amine-based light stabilizer, an alkali metal halide and copper iodide.

In these methods, an ultraviolet absorber (UVA) is used.
It is intended to improve the weather resistance by using a hindered amine light stabilizer together with a hindered amine light stabilizer.However, it is important to include a metal component such as a color grade using a pigment containing a metal component such as titanium oxide or a residual catalyst during resin polymerization. In the case of such a polyamide resin, there is a problem that the metal component reacts with UVA to form a complex, and the synergistic effect of the UVA light resistance cannot be obtained, so that the use thereof is limited.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to obtain sufficient weather resistance even in a polyamide resin containing a pigment containing a metal component such as titanium oxide and a residual catalyst containing a metal component. It is to provide a polyamide resin composition that exhibits the effect.

[0007]

Means for Solving the Problems As a result of intensive studies to solve this problem, the present inventors have found that by using a NOR type low molecular weight type and a high molecular weight type together as a hindered amine type light stabilizer. The inventors have found that the object can be achieved and arrived at the present invention.

That is, in the present invention, 0.05 to 2 parts by weight of N-O-R type low molecular weight type hindered amine type light stabilizer and high molecular weight type hindered amine type light stabilizer is added to 100 parts by weight of the total composition. The present invention relates to a polyamide resin composition containing excellent weather resistance. In addition, the present invention relates to a total of 100 parts by weight of the composition, 0.05 to 2 parts by weight of N-O-R low molecular weight type hindered amine light stabilizer and high molecular weight hindered amine light stabilizer, and a metal component. The present invention relates to a polyamide resin composition having excellent weather resistance, which comprises 0.2 to 7 parts by weight of a pigment containing

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
The polyamide resin that constitutes the composition of the present invention may be a known one. Examples thereof include various types of polyamide resins such as a lactam polycondensate, a diamine compound-dicarboxylic acid compound polycondensate, and an ω-aminocarboxylic acid polycondensate.

As the monomer component of the polyamide resin, an aliphatic diamine or aromatic diamine having 4 to 12 carbon atoms and an aliphatic dicarboxylic acid or aromatic dicarboxylic acid having 6 to 12 carbon atoms, or a lactam having 6 to 12 carbon atoms is used. Examples thereof include aminocarboxylic acids having 6 to 12 carbon atoms.

Specific examples of the aliphatic diamine include tetramethylenediamine, hexamethylenediamine, octamethylenediamine, nonamethylenediamine, undecamethylenediamine, dodecamethylenediamine and the like. Examples of aromatic diamines include metaxylylenediamine. Specific examples of the aliphatic dicarboxylic acid include adipic acid, heptanedicarboxylic acid, octanedicarboxylic acid, nonanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid and the like. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid.

Specific examples of the lactam include α-pyrrolidone, ε-caprolactam, ω-laurolactam, ε-enanthlactam and the like. Specific examples of the aminocarboxylic acid include 6-aminocaproic acid, 7-aminoheptanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid and the like.

Specific examples of the polyamide resin formed from these monomer components include nylon 6 and nylon 6
6, Nylon 12, Nylon 610, Nylon 6I, Nylon 6T, Nylon M6, etc., and their copolyamides such as Nylon 6/66, Nylon 66.
/ 610, nylon 66 / 6I, nylon 66 / 6T
Etc., and blends of these with each other. In the present invention, the polyamide resin is preferably a copolyamide. By using the copolyamide, the mechanical properties, especially the elongation retention rate, are increased.

The degree of polymerization of the polyamide resin in the present invention is not particularly limited, but 1 g of the polymer is added to 96% concentrated sulfuric acid 10
It was dissolved in 0 ml and the relative viscosity measured at 25 ° C. was 1.8 to
It is preferably 5.0, more preferably 2.0 to
It is 3.0. If the relative viscosity is higher than the upper limit of the above numerical value, the workability is significantly impaired, and if it is lower than the lower limit, the mechanical strength is lowered, which is not preferable.

The polyamide resin of the present invention preferably has an amino terminal group concentration higher than a carboxyl terminal group concentration. The concentration of amino end groups is 1 kg of polymer.
It is desirable that the amount is 50 meq or more, preferably 60 meq or more. Excessive concentration of amino end groups results in higher mechanical properties, especially retention of elongation.

A method for producing a polyamide resin having an amino terminal group concentration higher than a carboxyl terminal group concentration is not particularly limited, but a diamine compound is added at the time of polymerization or after the completion of the polymerization when the composition is extruded and kneaded. It can be obtained by including it. If produced during melt polymerization, a method of polymerizing by adding a diamine monomer in excess at the time of raw material charging, a method of polymerizing by adding a raw material monomer and a diamine compound other than the raw material monomer during raw material charging,
A method is used in which after a polyamide having a predetermined molecular weight is polymerized, a diamine compound is added immediately before the polymer is extracted from the polymerization tank so as to achieve a desired end group concentration balance. If it is produced after the polymerization, a method in which the polyamide resin after the polymerization and the diamine compound are melt-kneaded so as to achieve the desired end group concentration balance is used.

Specific examples of this diamine compound include, in addition to those used as a monomer of the above-mentioned polyamide resin, aliphatic diamines such as methylenediamine, ethylenediamine and trimethylenediamine, and aromatic diamines such as naphthalenediamine and metaxylylenediamine. Diamine is used, preferably hexamethylenediamine, dodecamethylenediamine, and metaxylylenediamine.

The polyamide resin composition of the present invention comprises an N-O-R low molecular weight type hindered amine light stabilizer and a high molecular weight hindered amine light stabilizer 0.05-2 based on 100 parts by weight of the total composition. Including parts by weight. The amount of hindered amine light stabilizer is 0.05
If it is less than 2 parts by weight, the weather resistance will be insufficient, and if it is more than 2 parts by weight, problems such as bleed-out will occur, which is not preferable.

The weight ratio of the N-O-R type low molecular weight type and the high molecular weight type hindered amine light-resistant stabilizer is such that the low molecular weight type: high molecular weight type = 1: 10 to 10: 1, preferably 1: 3 to 3 : 1 is desirable.

In the hindered amine light-resistant stabilizer used in the present invention, the low molecular weight type is one having an average molecular weight of 300 or more and less than 1,000, preferably 400 or more and 800 or less. The high molecular weight type has an average molecular weight of 1,000.
From the above, 5,000 or less, preferably 1500
From the above, it is 4000 or less.

The N—O—R type low molecular weight type hindered amine light-resistant stabilizer in the present invention is a compound having a structure of the following formula in the molecule.

[Chemical 2] (R ₁ , R ₂ , R ₃ , and R ₄ represent an alkyl group, and R ₅ represents an alkyl group, a cycloalkyl group, and an aryl group.)

Examples of the N—O—R type low molecular weight type hindered amine light fastness stabilizer include compounds represented by the following formula (1).

[Chemical 3]

The high molecular weight hindered amine-based light stabilizer used in the present invention is dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine succinate. Polycondensate, poly [{6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl -4-Piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}], N, N'-bis (3-aminopropyl) ethylenediamine-2,4-
Bis [N-butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,
3,5-triazine condensate, poly [(6-morpholine-
s-triazine-2,4-diyl) {(2,2,6,6
-Tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}] and the like.

In the present invention, the NOR type low molecular weight type and the high molecular weight type are used in combination as the hindered amine type light fastness stabilizer so that the light resistance is equal to or higher than that in the case of using UVA and the hindered amine type light fastness stabilizer in combination. The effect of is obtained. The reason is that the high molecular weight type hindered amine-based light stabilizer exhibits light stability for a long time, but when it is used alone, the light resistance reaction is slow, and therefore the light resistance effect does not appear quickly. On the other hand, the N—O—R type low molecular weight type hindered amine-based light resistance stabilizer exhibits a light resistance action more quickly than general N—H type hindered amine light resistance stabilizers, but a long-term effect cannot be expected. Therefore, by using both in combination, it is possible to rapidly exhibit a light resistance effect and to exhibit light stability for a long time.

In the polyamide resin composition of the present invention, other fillers and additives such as glass fiber, inorganic pigments, inorganic fillers, heat-resistant agents, crystal nucleating agents and crystallization accelerators are added depending on the required properties. , An antistatic agent, a flame retardant, a lubricant, a plasticizer, a foaming agent, a coloring agent, a stabilizer, a coupling agent and the like can be added.

As the inorganic pigment, titanium dioxide, carbon black, iron oxide, ultramarine or the like can be used. They are,
They may be used alone or in combination. In particular, titanium dioxide is preferable for use in white resin parts such as lighting equipment. Titanium dioxide is not particularly limited in particle size, and its crystalline form may be either rutile type or anatase type. In addition, Mn, Al, Zn, S
It is preferable that the titanium oxide surface is coated with a compound such as i. The total amount of inorganic pigment added is 1
0.2 to 7 parts by weight is preferable with respect to 00 parts by weight. In the present invention, the inorganic pigment also has an effect of resistance to light discoloration.

Examples of the heat-resistant agent include hindered phenols, phosphites and copper halides, which can be used alone or in combination. Hindered phenols include triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanedio-.
Rubis (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n
-Octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine, pentaerythrityl-tetrakis [3- (3,5-di-t]
-Butyl-4-hydroxyphenyl) propione-
G] 2,2-thio-diethylenebis [3- (3,5-
Di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N, N '.
-Hexamethylenebis (3,5-di-t-butyl-4-
Hydroxy-hydrocinnamamide), 3,5-di-t-
Butyl-4-hydroxy-benzylphosphonate-
Diethyl ester, 1,3,5-trimethyl-2,4,
6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene and the like can be mentioned, and preferably triethylene glycol-bis [3- (3-t-butyl-5-
Methyl-4-hydroxyphenyl) propionate],
Pentaerythrityl-tetrakis [3- (3,5-di-
t-butyl-4-hydroxyphenyl) propione-
], N, N′-hexamethylenebis (3,5-di-t
-Butyl-4-hydroxy-hydrocinnamamide).

Examples of phosphites include tris (2,4)
-Di-t-butylphenyl) phosphite, tetrakis (2,4-di-t-butylphenyl) -4,4'-biphenylene phosphonite.

The amount of the heat-resistant agent added is preferably 0.01 to 1 part by weight based on 100 parts by weight of the total composition.

Examples of the crystal nucleating agent include inorganic fillers such as talc and clay, and organic crystal nucleating agents such as fatty acid metal salts. These can be used alone or in combination. Examples of the crystallization accelerator include low molecular weight polyamides, higher fatty acids, higher fatty acid esters and higher aliphatic alcohols, which can be used alone or in combination. Examples of the release agent include fatty acid metal salts, fatty acid amides, and various waxes, which may be used alone or in combination. Examples of the antistatic agent include aliphatic alcohols, aliphatic alcohol esters and higher fatty acid esters, which may be used alone or in combination. Examples of the flame retardant include metal hydroxides such as magnesium hydroxide, phosphorus, ammonium phosphate, ammonium polyphosphate, melamine cyanurate, ethylene dimelamine dicyanurate, potassium nitrate, and chlorine-based flame retardants, which may be used alone or in these. Can be used in combination.

Other thermoplastic resins can be added to the polyamide resin of the present invention within the range not impairing the object of the present invention. Examples of thermoplastic resins used in combination are polyethylene, polypropylene, polystyrene, ABS resin, AS
Examples include general-purpose resin materials such as resins and acrylic resins, polycarbonate, polyphenylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, and other high heat resistant resins. Particularly when polyethylene or polypropylene is used in combination, it is desirable to use those modified with maleic anhydride, a glycidyl group-containing monomer or the like.

The polyamide resin composition of the present invention is preferably used for exterior parts of automobiles and railways, parts such as building materials and housing, and parts such as lighting equipment.

[0033]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[Mechanical Properties] According to ASTM D638,
Tensile strength and tensile elongation were measured using ASTM I pieces molded by injection molding. The degree of deterioration of physical properties due to weathering treatment is evaluated by comparing the characteristics before and after weathering treatment.

[ΔE (color difference)] According to JIS Z8730, the ASTMI No. piece molded by injection molding is subjected to weathering treatment,
L ^* , with Suga SM color computer SM5
The a ^* and b ^* were measured. Color difference ΔE = (ΔL ^{* 2} + Δa ^{* 2} + Δb ^{* 2} ) due to weathering due to the difference between L ^* , a ^* , and b ^* measured from the test pieces before and after weathering.
^0.5 was calculated. Based on this result, the change in color tone before and after the weather resistance treatment is evaluated.

[Composition used in Examples and Comparative Examples] PA6-1: Ube Industries, Ltd. 1013B (amino terminal group concentration 4.5 eq / g × 10 ⁻⁵ , carboxyl terminal group concentration 6.5 eq / g ×) ^10-5 ) PA6-2: Ube Industries, Ltd. 1013A (amino terminal group concentration 9.7 eq / g × 10 ⁻⁵ , carboxyl terminal group concentration 2.6 eq / g × 10 ⁻⁵ ) PA6 / 66: Ube Industries Ltd. Company-made 5013B Heat-resistant agent: Tominox 917 (Yoshitomi Pharmaceutical Co., Ltd. hindered phenol system) Heat-resistant agent: Irganox 1098 (Ciba Specialty Chemicals Co., Ltd.) Heat-resistant agent: Irgafos 168 (Ciba Specialty Chemicals) (Phosphite type manufactured by Co., Ltd.) Heat-resistant agent: Sandostab P-EPQ (Phosphite manufactured by Clariant Co., Ltd.) Onaito system) UV absorber: Tinuvin327 (manufactured by Ciba Specialty Chemicals Corp. benzotriazole) UV absorber: Tinuvin234 (manufactured by Ciba Specialty Chemicals Corp. benzotriazole) UV absorber: SanduvorVSU (Clariant
Oxalic acid anilide type manufactured by Co., Ltd. Weathering agent: Tinuvin 770 (NH type hindered amine type manufactured by Ciba Specialty Chemicals Co., Ltd., molecular weight 481) Weathering agent: Tinuvin 123 (N-O- manufactured by Ciba Specialty Chemicals Co., Ltd.) R-type hindered amine system,
Molecular weight 737) Weathering agent: Chimassorb 944 (N-H type hindered amine type, manufactured by Ciba Specialty Chemicals, molecular weight 2000 or more) Weathering agent: Chimassorb 119 (N-R hindered amine type, manufactured by Chiba Specialty Chemicals, molecular weight) 2000 or more) Pigment: Titanium oxide KR-480 (Titanium dioxide manufactured by Titanium Industry Co., Ltd.)

Examples 1 to 7 and Comparative Examples 1 to 5 Each composition shown in Table 1 was premixed by dry blending, and pellets were prepared by melt-kneading using TEM35B of Toshiba Machine Co., Ltd. The prepared sample is injection-molded by ASTM using Nestal SG75 manufactured by Sumitomo Heavy Industries, Ltd.
A No. I piece was molded. Using the obtained ASTMI piece,
Tensile strength and tensile elongation were measured.

Next, the oven device shown in FIG. 1 (Temperature Chamber MODEL PS-2 manufactured by Tabai Espec Co., Ltd.)
Using 2), a weather resistance test was conducted using the obtained ASTM I piece. In Fig. 1, Mercury Lamp H
Using 400, the distance from the center of the mercury lamp to the jig was set to 245 mm, the motor rotation speed was set to 60 rpm, the system temperature was set to 90 ° C., and accelerated tests were conducted for 7 days and 14 days. The tensile strength, tensile elongation, and ΔE (color difference) of the sample after the test were measured. ΔE in this case refers to the difference (color difference) from the sample not subjected to the accelerated test. The results obtained are shown in Table 1.

[0039]

[Table 1]

The polyamide resin composition of the present invention exhibits sufficient weather resistance even when it contains a pigment containing a metal component such as titanium oxide or a residual catalyst containing a metal component.
It is preferably used for automobiles, railway exteriors, parts such as building materials and housing, and parts such as lighting equipment.

[Brief description of drawings]

FIG. 1 is a schematic view of an oven device used for a weather resistance test.

Continued front page    F-term (reference) 4J002 CL011 CL031 CL051 CM022                       DA037 DE097 DE117 DE137                       EU086 FD042 FD046 FD060                       FD097 FD100 FD130 FD160                       FD200 GC00 GL00 GN00

Claims (7)

[Claims] 1. N- based on 100 parts by weight of the total composition.
O-R low molecular weight hindered amine light stabilizer and high molecular weight hindered amine light stabilizer 0.
A polyamide resin composition having excellent weather resistance, characterized in that the polyamide resin composition contains from 0 to 5 parts by weight. 2. N- based on 100 parts by weight of the total composition.
O-R low molecular weight hindered amine light stabilizer and high molecular weight hindered amine light stabilizer 0.
Pigment containing 0.5 to 2 parts by weight and a metal component 0.2 to 7
A polyamide resin composition having excellent weather resistance, which is characterized by containing parts by weight. 3. The polyamide resin composition according to claim 2, wherein the metal component of the components constituting the pigment contains titanium oxide. 4. The weight ratio of the NOR type low molecular weight type and the high molecular weight type hindered amine light stabilizer is
The polyamide resin composition according to claims 1 to 3, which is 1:10 to 10: 1. 5. The polyamide resin composition according to claim 1, wherein the N—O—R type low molecular weight type hindered amine light stabilizer is a compound represented by the following formula (1). [Chemical 1] 6. The polyamide resin composition according to claim 1, wherein the polyamide resin is a copolyamide resin. 7. The polyamide resin composition according to claim 1, wherein the amino terminal group concentration in the polyamide resin> the carboxyl terminal group concentration.