JP4067610B2 - Flame retardant polyamide composition - Google Patents

Description

【００４０】
【表２】

【００４１】
【表３】

【００４２】
なお、表１〜３において、註１、２は下記の通りである。
註１）ＰＥＧ４００：ポリエチレングリコール（数平均分子量４００）
註２）ＰＥＧ６０００：ポリエチレングリコール（数平均分子量６０００）
【００４３】
【発明の効果】
本発明の組成物は、難燃性が極めて高く、かつ成形加工時の難燃剤による金型汚染性が少なく、更には耐熱変色性に優れた成形材料であり、家電部品、電子部品、自動車部品等の用途に用いることが出来る。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flame retardant polyamide resin composition. In particular, the present invention relates to a flame retardant polyamide resin composition suitably used for parts materials such as connectors in the electrical / electronic field and electrical parts in the automotive field. In particular, the present invention relates to a flame-retardant polyamide resin composition excellent in heat resistance, which has very little mold contamination by a flame retardant during molding and has very little thermal discoloration during molding.
[0002]
[Prior art]
Conventionally, polyamide resins have been used in fields such as automobile parts, machine parts, and electric / electronic parts because they are excellent in mechanical strength, heat resistance, and the like. In particular, in recent years, the level of demand for flame retardancy has become higher in applications for electrical and electronic parts, and higher flame retardancy is required than the self-extinguishing properties inherent in polyamide resins. UL- of the Underwriters Laboratory Many studies have been made to improve the flame retardant level conforming to the 94 standard.
[0003]
For example, polyamide resin compositions obtained by blending melamine cyanurate with polyamide resin are well known (Japanese Patent Laid-Open Nos. 53-31759 and 53-12559). This composition is an excellent flame retardant composition having a high flame retardant level and less bleeding out. However, the composition obtained by this technique has a problem that the melamine cyanurate is firmly fixed to the mold surface during injection molding, so that it is necessary to periodically clean the mold surface. Due to the difference in temperature and the slight difference in the drying temperature of the pellets before molding, there is a problem that the color tone of the obtained molded product is different and the defect rate is high, and it is not necessarily a composition with excellent molding productivity. There wasn't.
[0004]
For this reason, an attempt to improve mold contamination by adding an aliphatic carboxylic acid metal salt and a nonionic surfactant (Japanese Patent Laid-Open No. 8-157712), molding by adding an inorganic phosphorus compound or an organic phosphorus compound Attempts have been made to prevent color tone fluctuations of products (JP-A-3-54252, JP-A-3-76756, and JP-A-7-18179), but only compositions obtained by any of the prior arts. In addition, even a composition obtained by combining these technologies cannot improve the mold contamination and the color tone variation of the molded product at the same time. There was a craving for a very high flame retardant polyamide resin composition.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a flame-retardant polyamide resin composition excellent in heat resistance, which has very little mold fouling by a flame retardant during molding and has very little thermal discoloration during molding. .
[0006]
[Means for Solving the Problems]
As a result of extensive research, the present inventor has achieved the purpose for the first time when a specific phosphoric acid triester, a higher fatty acid metal salt and a polyhydric alcohol are combined in a system comprising a polyamide resin and melamine cyanurate. Based on this finding, the present invention has been completed.
[0007]
That is, the present invention is as follows.
1) (a) 100 parts by weight of polyamide resin, (b) 2 to 20 parts by weight of melamine cyanurate, (c) 0.005 to 1.5 parts by weight of phosphoric acid trialkyl ester, (d) having 9 to 30 carbon atoms A flame retardant polyamide composition comprising 0.01 to 5 parts by weight of a higher fatty acid metal salt and (e) 0.01 to 5 parts by weight of polyethylene glycol .
[0008]
2) (c) The trialkyl phosphate is at least one selected from trimethyl phosphate, triethyl phosphate, tri-n-propyl phosphate, and tri-n-butyl phosphate. The flame retardant polyamide composition according to 1 above.
3) The flame retardant polyamide composition according to 1 or 2 above, wherein (d) the higher fatty acid metal salt is at least one selected from calcium stearate and aluminum stearate.
[0010]
Hereinafter, the present invention will be described in detail.
The polyamide resin (a) used in the present invention is an aliphatic polyamide such as 46 nylon, 6 nylon, 66 nylon, 610 nylon, 612 nylon, 11 nylon, 12 nylon, hexamethylene terephthalamide, tetramethylene isophthalamide, hexa Examples thereof include aromatic polyamides containing aromatic components such as terephthalic acid such as methylene isophthalamide and metaxylylene adipamide, isophthalic acid and xylylenediamine, and copolymerized polyamides and mixed polyamides containing these as main constituents. In particular, 6 nylon, 66 nylon, 46 nylon, and copolymer of 66 nylon and 6 nylon are preferable in terms of heat resistance and molding processability. There is no restriction | limiting in particular about the molecular weight of the polyamide resin used here, The thing of the range whose sulfuric acid relative viscosity (JIS-K6180) is 1.5-4.5 can be used arbitrarily.
[0011]
Melamine cyanurate (b) used in the present invention is an equimolar reaction product of melamine and cyanuric acid, for example, stirring and mixing an aqueous melamine solution and an aqueous cyanuric acid solution at a temperature of about 90 to 100 ° C. It is obtained by precipitating and filtering the product obtained by the reaction. The obtained product is a white solid and is preferably pulverized into a fine powder.
[0012]
The compounding quantity of a melamine cyanurate is 2-20 weight part with respect to 100 weight part of polyamide resins, Preferably it is 3-15 weight part. If it is less than 2 parts by weight, the flame retardant effect is small, and if it exceeds 20 parts by weight, the quantitative flame retardant improvement effect is not seen, but it is not preferable because the physical properties and moldability are impaired. Any known method can be applied to blending melamine cyanurate into the polyamide resin, but industrially, a method of kneading and blending with an extruder or the like is preferred.
[0013]
The trialkyl phosphate (c) used in the present invention is trimethyl phosphate, triethyl phosphate, tri-n-propyl phosphate, tri-i-propyl phosphate, tri-n-butyl phosphate, triphosphate. -I-butyl, tri-n-pentyl phosphate, tri-n-hexyl phosphate, tri-n-octyl phosphate, tri (2-ethylhexyl) phosphate and the like. The amount of these trialkyl phosphates added is usually 0.005 to 3 parts by weight, particularly preferably 0.01 to 1.5 parts by weight, based on 100 parts by weight of the polyamide resin. When the amount added is less than 0.005 parts by weight, no effect is seen in improving the thermal discoloration during molding, and it tends to be colored yellow due to slight differences in the molding temperature and the drying temperature of the pellets. Will fluctuate. Further, even if the addition amount is more than 3 parts by weight, the heat resistance stability of the obtained polyamide resin composition is not further improved.
[0014]
The addition time of the trialkyl phosphate is not particularly limited, and can be added at any stage before, during and after the polymerization of the polyamide resin. In particular, it is particularly preferable to add a trialkyl phosphate when kneading a polyamide resin and melamine cyanurate using an extruder because it is more effective in preventing thermal discoloration. Moreover, these trialkyl phosphates may be used alone or in combination of two or more. Trimethyl phosphate, triethyl phosphate, tri-n-propyl phosphate, and tri-n-butyl phosphate are particularly preferable because of their high anti-coloring effect. Furthermore, trimethyl phosphate is most preferable in that there is no decrease in physical properties.
[0015]
The higher fatty acid metal salt (d) used in the present invention is a carbon number such as capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, serotic acid, montanic acid, mellicic acid, oleic acid, erucic acid, etc. Examples of sodium salts, lithium salts, calcium salts, magnesium salts, zinc salts, and aluminum salts of 9 to 30 higher aliphatic carboxylic acids include, among these higher fatty acid metal salts, stearic acid metal salts, In particular, calcium stearate, magnesium stearate, zinc stearate, and aluminum stearate are particularly preferable because they do not reduce the flame retardancy of the finally obtained polyamide resin composition. Furthermore, calcium stearate and aluminum stearate are the most preferable from the viewpoint of less gas generation during molding.
[0016]
The addition amount of these higher fatty acid metal salts is usually 0.01 to 5 parts by weight, particularly preferably 0.03 to 3 parts by weight, based on 100 parts by weight of the polyamide resin. When the amount added is less than 0.01 parts by weight, the effect of preventing adhesion of melamine cyanurate to the mold during molding is not recognized, and even when the amount exceeds 5 parts by weight, the effect of preventing quantitative adhesion is seen. Rather, it is not preferable because gas is generated during molding and new problems such as a reduction in flame retardancy occur. These higher fatty acid metal salts may be used alone or in combination of two or more.
[0017]
As a method for adding a higher fatty acid metal salt, various methods can be used at an arbitrary stage before molding. Examples thereof include a method of dry blending with a polyamide resin, a method of melt-kneading using an extruder after dry blending, a method of coating the surface of polyamide resin pellets, and the like.
Examples of the polyhydric alcohol and ester derivative (e) used in the present invention include glycols such as polyethylene glycol, polypropylene glycol, ethylene glycol, diethylene glycol, trimethylene glycol, and propylene glycol, 1,4 butanediol, and 1,5 pentadiol. Diols such as 1,6 hexanediol, polyhydric alcohols such as glycerin and pentaerythritol, sorbitan monolaurate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, polyoxyethylene sorbitan monolaurate, poly Examples thereof include ester derivatives of polyhydric alcohols such as oxyethylene sorbitan monostearate and polyoxyethylene sorbitan monooleate.
[0018]
Among these, polyethylene glycol is particularly preferable because it has a large effect as a dispersant for melamine cyanurate. The number average molecular weight of polyethylene glycol is preferably in the range of 200 to 10,000 from the viewpoints of releasability, flame retardancy, gas generation during molding, and the like. A particularly preferred molecular weight is 300 to 7000.
[0019]
The addition of the polyhydric alcohol component (e) has an effect of suppressing secondary aggregation of the melamine cyanurate dispersed in the polyamide resin, but when added in combination with a higher fatty acid metal salt, it is in a molten state during injection molding. The effect of preventing the phenomenon that melamine cyanurate partially separates from the polyamide resin and sticks to the mold surface is remarkably improved, and mold contamination peculiar to the melamine cyanurate-containing polyamide resin is not recognized even if molded for a long time. . The addition amount of the polyhydric alcohol component is usually 0.01 to 5 parts by weight, preferably 0.03 to 3 parts by weight. When the addition amount is less than 0.01, the effect of preventing melamine cyanurate from sticking to the mold is small, and when it exceeds 5 parts by weight, the flame retardancy of the flame retardant polyamide resin composition finally obtained Is significantly reduced.
[0020]
As a method for adding the polyhydric alcohol component, any known method can be used at any stage before molding, but the effect of the present invention is further manifested particularly when added in the presence of a higher fatty acid metal salt. Therefore, for example, there are a method of blending with a polyamide resin and a higher fatty acid metal salt using a blender, a method of melt-kneading with an extruder after blending, a method of coating or adhering to a polyamide resin pellet together with a higher fatty acid metal salt. Can be mentioned.
[0021]
In the flame-retardant polyamide resin composition of the present invention, other components, for example, colorants such as pigments and dyes, heat stabilizers, oxidation deterioration inhibitors, and weather resistance improvements are within the range not impairing the object of the present invention. Additives such as an agent, a nucleating agent, a plasticizer, a lubricant and an antistatic agent, and other resin polymers can be added.
The composition of the present invention is molded into various molded products for electrical, electronic, and automotive applications such as connectors, coil bobbins, breakers, holders, plugs, switches, and the like by known methods such as injection molding, extrusion molding, and blow molding.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to these Examples. In addition, the measuring method used for the Example and the comparative example is shown below.
(1) Flame retardancy;
The measurement was carried out according to the method of UL94 (standard established by Under Writers Laboratories Inc., USA). The thickness of the test piece was 1/32 inch, and it was obtained by molding using an injection molding machine (Toshiba Machine: IS50EP).
[0023]
(2) Fixing property of melamine cyanurate to the mold surface;
Using an injection molding machine (manufactured by Nissei Plastic Industry; PS40E) with a mold attached, under the molding conditions shown below, after the 1,500 shot molding, the mold was disassembled and the state attached to the mold surface was observed, The fixing property of melamine cyanurate was determined as follows.
(Fixability criteria)
A: No fixed matter is observed.
[0024]
◯: A thin film-like fixed substance was observed, but can be easily removed by simply wiping with gauze.
X: A fixed substance firmly adhered to the surface of the mold is observed, and this fixed substance needs to be removed by strongly polishing with a metal brush.
(Molding condition)
・ Cylinder setting temperature: Nozzle part 260 ° C, front part 265 ° C, middle part 265 ° C, rear part 265 ° C
・ Mold set temperature: 80 ℃
Molding cycle: injection 1.2 seconds, cooling 5.0 seconds, intermediate 1.0 seconds Injection speed: 99%
・ Injection pressure: 43%
(3) Thermal discoloration;
Using an injection molding machine (manufactured by Toshiba Machine; IS90B), a flat plate (66 mm × 90 mm × 2 mm) was molded at the two levels of molding temperatures shown below, and the yellowing degree [YI] of the obtained flat plate was determined according to JISK7105. It calculated | required using the color difference meter (Nippon Denshoku Industries make; color difference meter ND-1001DP).
[0025]
The lower the yellowing degree “YI”, the more the molded product color tone is white and the higher the heat discoloration, and the smaller the difference in yellowing degree “YI” between the molded products obtained by changing the molding conditions, the more the molding conditions change. Indicates a stable color tone.
(Molding condition 1)
・ Cylinder set temperature: 265 ℃ (flat)
・ Mold set temperature: 80 ℃
Molding cycle: injection 5.0 seconds, cooling 10.0 seconds, intermediate 2.0 seconds Injection speed: 40%
・ Injection pressure: 22%
(Molding condition 2)
・ Cylinder set temperature: 275 ℃ (flat)
・ Mold set temperature: 80 ℃
Molding cycle: injection 5.0 seconds, cooling 10.0 seconds, intermediate 2.0 seconds Injection speed: 40%
・ Injection pressure: 22%
[0026]
[Example 1]
100 parts by weight of nylon 66 (Asahi Kasei Kogyo; Leona 1200), 7 parts by weight of melamine cyanurate (Mitsubishi Chemical; MCA-CO), 0.04 parts by weight of trimethyl phosphate (Kishida Chemical; first grade reagent), calcium stearate ( After mixing 0.2 parts by weight of Sakai Chemical Industry Co., Ltd .; SC-100) and 0.2 parts by weight of polyethylene glycol (manufactured by Sanyo Chemical; PEG400: number average molecular weight of about 400) with a Henschel mixer, this mixture was mixed with a twin-screw extruder. It was melt-kneaded with (Ikegai Iron Works; PCM45), the strand was cooled and solidified, and a pellet was obtained with a pelletizer.
[0027]
The obtained pellets were dried and then injection molded to evaluate various properties. The results are shown in Table 1.
[0028]
[Examples 2 and 3]
Various characteristics were evaluated in the same manner as in Example 1 except that the amount of trimethyl phosphate was changed to the blending amount shown in Table 1. The results are shown in Table 1.
[0029]
[Example 4]
Various characteristics were evaluated in the same manner as in Example 1 except that tri-n-butyl phosphate (manufactured by Kishida Chemical; primary reagent) was used instead of trimethyl phosphate. The results are shown in Table 1.
[0030]
[Comparative Example 1]
Various characteristics were evaluated in the same manner as in Example 1 except that trimethyl phosphate was not used. The results are shown in Table 1.
[0031]
[Comparative Example 2]
Various characteristics were evaluated in the same manner as in Example 1 except that triphenyl phosphate (manufactured by Kishida Chemical Co., Ltd .; primary reagent) was used instead of trimethyl phosphate. The results are shown in Table 2.
[0032]
[Comparative Example 3]
Various characteristics were evaluated in the same manner as in Example 1 except that di-n-butyl phosphate (manufactured by Kishida Chemical Co., Ltd .; primary reagent) was used instead of trimethyl phosphate. The results are shown in Table 2.
[0033]
[Example 5]
Example 1 except that trimethyl phosphate, aluminum stearate (manufactured by Sakai Chemical; SA-1000)) and polyethylene glycol (manufactured by Sanyo Chemical; PEG 6000: number average molecular weight of about 6000) were changed to the compositions shown in Table 2. It implemented similarly and various characteristics were evaluated. The results are shown in Table 2.
[0034]
[Example 6]
Various characteristics were evaluated in the same manner as in Example 6 except that the amount of aluminum stearate was 1.0 part by weight. The results are shown in Table 2.
[0035]
[Example 7]
The same procedure as in Example 1 was performed except that trimethyl phosphate, calcium montanate (manufactured by Hoechst Japan; Hostamont CaV102), polyethylene glycol (manufactured by Sanyo Chemical; PEG 6000: number average molecular weight of about 6000) were changed to the compositions shown in Table 2. Various characteristics were evaluated. The results are shown in Table 2.
[0036]
[Comparative Example 4]
It carried out similarly to Example 7 except not using calcium montanate, and various characteristics were evaluated. The results are shown in Table 3.
[0037]
[Comparative Example 5]
Various characteristics were evaluated in the same manner as in Example 7 except that polyethylene glycol (manufactured by Sanyo Chemical; PEG 6000: number average molecular weight of about 6000) was not used. The results are shown in Table 3.
[0038]
[Comparative Examples 6 and 7]
Various characteristics were evaluated in the same manner as in Example 8 except that the amounts of calcium montanate and polyethylene glycol were changed to the compositions shown in Table 3. The results are shown in Table 3.
[0039]
[Table 1]

[0040]
[Table 2]

[0041]
[Table 3]

[0042]
In Tables 1 to 3, 註 and 1 are as follows.
註 1) PEG400: Polyethylene glycol (number average molecular weight 400)
2) PEG 6000: Polyethylene glycol (number average molecular weight 6000)
[0043]
【The invention's effect】
The composition of the present invention is a molding material having extremely high flame retardancy, low mold contamination due to a flame retardant during molding, and excellent heat discoloration. Home appliance parts, electronic parts, automobile parts It can be used for such applications.

Claims (3)

(A) 100 parts by weight of a polyamide resin, (b) 2 to 20 parts by weight of melamine cyanurate, (c) 0.005 to 1.5 parts by weight of phosphoric acid trialkyl ester, (d) a higher fatty acid having 9 to 30 carbon atoms A flame retardant polyamide composition comprising 0.01 to 5 parts by weight of a metal salt and (e) 0.01 to 5 parts by weight of polyethylene glycol .   (C) The trialkyl phosphate is at least one selected from trimethyl phosphate, triethyl phosphate, tri-n-propyl phosphate, and tri-n-butyl phosphate. The flame-retardant polyamide composition according to 1.   (D) The flame retardant polyamide composition according to claim 1 or 2, wherein the higher fatty acid metal salt is at least one selected from calcium stearate and aluminum stearate.