JPH11106645A - Flame-resistant polyamide composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition extremely little in mold staining and thermal discoloration caused by a flame retardant on molding processing and excellent in heat resistance by including a polyamide resin, a melamine cyanurate, a trialkyl phosphate, a higher fatty acid metal salt, and a polyhydric alcohol in specific amounts, respectively. SOLUTION: This flame-resistant polyamide composition comprises (A) 100 pts.wt. of a polyamide resin (e.g. 6-nylon, a copolymer of 6-nylon with 66-nylon), (B) 2-20 pts.wt. of a melamine cyanurate (e.g. the equimolar reaction product of melamine with cyanuric acid), (C) 0.005-3 pts.wt. of a trialkyl phosphate ester (preferably trimethyl phosphate ester), (D) 0.01-5 pts.wt. of a higher fatty acid metal salt (preferably calcium stearate, aluminum stearate), and (E) 0.01-5 pts.wt. of a polyhydric alcohol and/or its ester derivative (preferably polyethylene glycol).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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 as a component material for components such as connectors in the electric and electronic fields and electrical components in the automotive field. In particular, the present invention relates to a flame-retardant polyamide resin composition having extremely low mold contamination due to a flame retardant during molding and having extremely low heat discoloration during molding and excellent heat resistance.

[0002]

2. Description of the Related Art Conventionally, polyamide resins have a high mechanical strength,
Because of its excellent heat resistance, automotive parts, machine parts,
Used in fields such as electric and electronic components. In particular, in recent years, the demand level for flame retardancy has become increasingly higher in electric and electronic parts applications, and a higher degree of flame retardancy than the self-extinguishing property inherent to polyamide resin has been required. Underwriters Laboratory's UL- Numerous studies have been made to improve the flame retardant level conforming to the 94 standard.

For example, a polyamide resin composition obtained by blending melamine cyanurate with a polyamide resin is well known (JP-A-53-31759 and JP-A-53-53759).
No. 125549). This composition is an excellent flame-retardant composition having a high flame-retardant level and low bleed-out. However, the composition obtained by this technique has the problem that melamine cyanurate firmly adheres 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 pellet before molding, there is a problem that the color tone of the obtained molded product is different and the rejection rate is high. Did not.

[0004] For this reason, an attempt to improve mold contamination by adding a metal salt of an aliphatic carboxylic acid and a nonionic surfactant (Japanese Patent Laid-Open No. 8-157712) or adding an inorganic phosphorus compound or an organic phosphorus compound is disclosed. (Japanese Patent Application Laid-Open Nos. 3-54252 and 3-7)
No. 6,756, JP-A-7-18179). However, not only compositions obtained by any of the prior arts, but also compositions obtained by combining these techniques, molds It was not possible to obtain a resin composition in which both the stainability and the color tone fluctuation of the molded article were improved at the same time, and a flame-retardant polyamide resin composition having a very high productivity and solving these problems at once was in great demand.

[0005]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a flame-retardant polyamide which has extremely low mold contamination by a flame retardant at the time of molding and has extremely low heat discoloration at the time of molding. It is to provide a resin composition.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a system comprising a polyamide resin and melamine cyanurate is combined with a specific phosphoric acid triester, a metal salt of a higher fatty acid and a polyhydric alcohol. When blended,
It has been found for the first time that the object can be achieved, and based on this finding, the present invention has been completed.

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 3 parts by weight of trialkyl phosphate, (d) 0.01 to metal salt of higher fatty acid. A flame-retardant polyamide composition comprising 5 parts by weight and (e) 0.01 to 5 parts by weight of a polyhydric alcohol and / or an ester derivative thereof.

2) that (c) the trialkyl phosphate is at least one selected from trimethyl phosphate, triethyl phosphate, tri-n-propyl phosphate and tri-n-butyl phosphate; 2. The flame-retardant polyamide composition according to the above item 1, wherein (3) The flame-retardant polyamide composition as described in (1) or (2) above, wherein (d) the higher fatty acid metal salt is at least one selected from calcium stearate and aluminum stearate.

(4) The flame-retardant polyamide composition as described in any one of (1) to (3) above, wherein the polyhydric alcohol is polyethylene glycol. 5) wherein (c) the trialkyl phosphate is trimethyl phosphate, (d) the higher fatty acid metal salt is calcium stearate and / or aluminum stearate, and (e) the polyhydric alcohol is polyethylene glycol. The flame-retardant polyamide composition according to 1.

Hereinafter, the present invention will be described in detail. The polyamide resin (a) used in the present invention is 46 nylon, 6 nylon,
Aliphatic polyamides such as nylon, 66 nylon, 610 nylon, 612 nylon, 11 nylon, 12 nylon, hexamethylene terephthalamide, tetramethylene isophthalamide, hexamethylene isophthalamide,
Aromatic polyamides containing aromatic components such as terephthalic acid, isophthalic acid, xylylenediamine and the like such as meta-xylylene adipamide, and copolymerized polyamides and mixed polyamides containing these as main components. In particular, in terms of heat resistance and moldability, nylon 6, nylon 66,
Nylon 6 and copolymers of nylon 66 and nylon 6 are preferred. There is no particular limitation on the molecular weight of the polyamide resin used here, and the relative viscosity of sulfuric acid (JIS-K61
80) in the range of 1.5 to 4.5 can be arbitrarily used.

The melamine cyanurate (b) used in the present invention is an equimolar reaction product of melamine and cyanuric acid. For example, a melamine aqueous solution and a cyanuric acid aqueous solution are stirred at a temperature of about 90 to 100 ° C. It is obtained by precipitating and filtering the product obtained by mixing and reacting. The obtained product is a white solid, and is preferably used by pulverizing it into a fine powder.

The amount of melamine cyanurate is 2 to 20 parts by weight, preferably 3 to 15 parts by weight, based on 100 parts by weight of the polyamide resin. If the amount is less than 2 parts by weight, the flame-retarding effect is small, and if it is more than 20 parts by weight, the effect of quantitatively improving the flame-retardancy is not seen, but rather the physical properties and the formability are impaired, which is not preferable. Any known method can be used for blending melamine cyanurate with the polyamide resin, but a method of kneading and blending with an extruder or the like is industrially preferable.

The trialkyl phosphate (c) used in the present invention includes trimethyl phosphate, triethyl phosphate,
Tri-n-propyl phosphate, tri-i-propyl phosphate, tri-n-butyl phosphate, tri-i-butyl phosphate, tri-n-pentyl phosphate, tri-n-hexyl phosphate, phosphoric acid Tri-n-octyl, tri (2-ethylhexyl) phosphate and the like. The addition amount of these trialkyl phosphates is usually 0.005 to 3 parts by weight, particularly preferably 0.01 to 1.5 parts by weight, per 100 parts by weight of the polyamide resin. The amount added is 0.
If the amount is less than 005 parts by weight, the effect of improving the thermochromic property at the time of molding processing is not seen. Become. 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.

The timing of adding the trialkyl phosphate is not particularly limited, and it can be added at any stage before, during, or after the polymerization of the polyamide resin. In particular, when a polyamide resin and melamine cyanurate are kneaded using an extruder, the addition of a trialkyl phosphate is particularly preferable because it is more effective in preventing thermal discoloration. 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 preferred because they have a high effect of preventing coloration. Further, trimethyl phosphate is most preferable in that there is no decrease in physical properties.

The higher fatty acid metal salt (d) used in the present invention includes capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, serotinic acid, montanic acid, melicic acid, oleic acid, erucic acid and the like. Carbon number 9
Examples of the sodium salt, lithium salt, calcium salt, magnesium salt, zinc salt, aluminum salt and the like of the above higher aliphatic carboxylic acids, among these higher fatty acid metal salts, metal stearic acid salts, specifically, , Calcium stearate, magnesium stearate, zinc stearate, and aluminum stearate are particularly preferred because they do not reduce the flame retardancy of the finally obtained polyamide resin composition. Further, calcium stearate and aluminum stearate are most preferred because they generate less gas during molding.

The amount of the higher fatty acid metal salt to be added is usually 0.01 to 5 parts by weight, particularly preferably 0.03 to 3 parts by weight, per 100 parts by weight of the polyamide resin.
When the amount added is less than 0.01 part by weight, the effect of preventing melamine cyanurate from sticking to the mold at the time of molding is not recognized, and even when the amount is more than 5 parts by weight, the quantitative effect of preventing adhesion is observed. However, it is not preferable because gas generation occurs during molding and new problems such as a decrease in flame retardancy occur. These higher fatty acid metal salts may be used alone or in combination of two or more.

As a method of adding the higher fatty acid metal salt, various methods can be used at any stage before molding. For example, 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 a polyamide resin pellet, and the like can be mentioned. The polyhydric alcohol and its ester derivative (e) used in the present invention include polyethylene glycol,
Glycols such as polypropylene glycol, ethylene glycol, diethylene glycol, trimethylene glycol and propylene glycol; diols such as 1,4 butanediol, 1,5 pentadiol and 1,6 hexanediol; polyvalent such as glycerin and pentaerythritol Alcohol and polyhydric alcohols such as sorbitan monolaurate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate Ester derivatives are mentioned.

Of these, polyethylene glycol is particularly preferred because of its high effect as a dispersant for melamine cyanurate. Further, the number average molecular weight of the polyethylene glycol is preferably in the range of 200 to 10,000 from the viewpoints of mold releasability, flame retardancy, gas generation during molding, and the like. Particularly preferred molecular weight is 300-7000.

The addition of the polyhydric alcohol component (e) has the effect of suppressing the secondary aggregation of melamine cyanurate dispersed in the polyamide resin. The effect of preventing the phenomenon of melamine cyanurate being partially separated from the molten polyamide resin and sticking to the mold surface is significantly improved, and mold contamination peculiar to the melamine cyanurate-containing polyamide resin even after molding for a long time is greatly improved. Will not be recognized. 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. If the amount is less than 0.01, the effect of preventing melamine cyanurate from sticking to the mold is small, and if it exceeds 5 parts by weight, the flame retardancy of the finally obtained flame-retardant polyamide resin composition Is significantly reduced.

As a method for adding the polyhydric alcohol component, any known method can be used at an arbitrary stage before molding. Particularly, when the polyhydric alcohol component is added in the presence of a metal salt of a higher fatty acid, the effect of the present invention is reduced. Because it is expressed more, for example,
Examples of the method include a method of blending a polyamide resin and a higher fatty acid metal salt with a blender, a method of melt-kneading with an extruder or the like after blending, and a method of coating or attaching polyamide resin pellets together with the higher fatty acid metal salt.

The flame-retardant polyamide resin composition of the present invention contains other components such as a coloring agent such as a pigment and a dye, a heat stabilizer, an antioxidant, and the like, as long as the object of the present invention is not impaired. Additives such as a weather resistance improver, 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 formed into various molded products for electric, electronic, and automotive applications such as connectors, coil bobbins, breakers, holders, plugs, and switches by known methods such as injection molding, extrusion molding, and blow molding.

[0022]

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. The measurement methods used in Examples and Comparative Examples are shown below. (1) Flame retardancy; UL94 (Under Write, USA)
rs Laboratories Inc.). The thickness of the test piece was 1/32 inch, and an injection molding machine (TOSHIBA MACHINE: IS
50 EP).

(2) Adhesion of melamine cyanurate to the surface of a mold; using an injection molding machine (manufactured by Nissei Plastics Industries; PS40E) equipped with a mold under the following molding conditions,
After 500 shot molding, the mold was disassembled and the state of adhesion to the mold surface was observed, and the sticking property of melamine cyanurate was determined as follows. (Criteria for determining sticking property) A: No sticking matter is observed at all.

Δ: A thin film-like adhered substance was observed, but it can be easily removed only by wiping with gauze. X: A fixed substance firmly adhered to the mold surface is observed, and the fixed substance needs to be strongly polished and removed with a metal brush. (Molding conditions) Cylinder set temperature: nozzle part 260 ° C, front part 265
° C, middle part 265 ° C, rear part 265 ° C ・ Mold setting temperature: 80 ° C ・ Molding cycle: Injection 1.2 seconds, cooling 5.0 seconds, intermediate 1.0 second ・ Injection speed: 99% ・ Injection pressure: 43% (3) Thermochromic property; injection molding machine (manufactured by Toshiba Machine; IS90
Using B), a flat plate (66 mm × 90 mm × 2 mm) is formed at the following two levels of forming temperature, and the yellowing degree [YI] of the obtained flat plate is measured according to JIS K7105 by a color difference meter (manufactured by Nippon Denshoku Industries Co., Ltd.). A color difference meter ND-1001DP).

The lower the yellowing degree "YI", the whiter the molded article color tone and the higher the heat-resistant discoloration property, and the smaller the difference in the yellowing degree "YI" between the molded articles obtained by changing the molding conditions. This means that a stable color tone is exhibited with respect to fluctuations in molding conditions. (Molding condition 1) ・ Cylinder set temperature: 265 ° C (flat) ・ Mold set temperature: 80 ° C ・ 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 ° C (flat) ・ Mold set temperature: 80 ° C ・ Molding cycle: Injection 5.0 seconds, cooling 10.0 seconds, middle 2.0 seconds・ Injection speed: 40% ・ Injection pressure: 22%

[0026]

Example 1 Nylon 66 (manufactured by Asahi Kasei Corporation; Leona 12)
00) 100 parts by weight, melamine cyanurate (manufactured by Mitsubishi Chemical; MCA-CO) 7 parts by weight, trimethyl phosphate (manufactured by Kishida Chemical; first grade reagent) 0.04 parts by weight, calcium stearate (manufactured by Sakai Chemical Industry; SC-100) ) 0.2 parts by weight and polyethylene glycol (manufactured by Sanyo Chemical; PEG40)
0: number average molecular weight: about 400) and 0.2 parts by weight with a Henschel mixer. The mixture was melt-kneaded with a twin-screw extruder (PCM45, manufactured by Ikegai Iron Works), the strand was cooled and solidified, and pellets were obtained with a pelletizer. Was.

After the obtained pellets were dried, they were injection-molded to evaluate various properties. Table 1 shows the results.

[0028]

Examples 2 and 3 The same procedures as in Example 1 were carried out except that the amount of trimethyl phosphate was changed to the amount shown in Table 1, and various characteristics were evaluated. Table 1 shows the results.

[0029]

Example 4 Tri-phosphate was used in place of trimethyl phosphate.
The procedure was performed in the same manner as in Example 1 except that n-butyl (manufactured by Kishida Chemical; primary reagent) was used, and various properties were evaluated. Table 1 shows the results.

[0030]

Comparative Example 1 The same operation as in Example 1 was carried out except that trimethyl phosphate was not used, and various characteristics were evaluated. Table 1 shows the results.

[0031]

Comparative Example 2 The same procedure as in Example 1 was carried out except that triphenyl phosphate (manufactured by Kishida Chemical; primary reagent) was used instead of trimethyl phosphate, and various characteristics were evaluated. Table 2 shows the results.

[0032]

Comparative Example 3 Di-n phosphate instead of trimethyl phosphate
The same procedures as in Example 1 were carried out except that -butyl (manufactured by Kishida Chemical; primary reagent) was used, and various properties were evaluated. Table 2 shows the results.

[0033]

Example 5 Except that trimethyl phosphate, aluminum stearate (manufactured by Sakai Chemical; SA-1000) and polyethylene glycol (manufactured by Sanyo Chemical; PEG6000: number average molecular weight: about 6000) were changed to the compositions shown in Table 2. Is Example 1
And the characteristics were evaluated. Table 2 shows the results.

[0034]

Example 6 The same procedure as in Example 6 was carried out except that the amount of aluminum stearate was changed to 1.0 part by weight, and various characteristics were evaluated. Table 2 shows the results.

[0035]

Example 7 Trimethyl phosphate, calcium montanate (Hoestmont Japan; Hostamont CaV10)
2), polyethylene glycol (manufactured by Sanyo Chemical; PEG6)
000: number average molecular weight of about 6000), except that the composition was as shown in Table 2, and various properties were evaluated. Table 2 shows the results.

[0036]

Comparative Example 4 The same operation as in Example 7 was carried out except that calcium montanate was not used, and various characteristics were evaluated. Table 3 shows the results.

[0037]

Comparative Example 5 Polyethylene glycol (manufactured by Sanyo Chemical; P
EG6000: number average molecular weight of about 6000) was not used, and various properties were evaluated.
Table 3 shows the results.

[0038]

Comparative Examples 6 and 7 The same procedures as in Example 8 were carried out except that the amounts of calcium montanate and polyethylene glycol were changed to the compositions shown in Table 3, and various characteristics were evaluated. Table 3 shows the results.

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

[Table 3]

In Tables 1 to 3, notes 1 and 2 are as follows. Note 1) PEG400: polyethylene glycol (number average molecular weight 400) Note 2) PEG6000: polyethylene glycol (number average molecular weight 6000)

[0043]

Industrial Applicability The composition of the present invention is a molding material having extremely high flame retardancy, low mold contamination by a flame retardant during molding, and excellent heat discoloration resistance. It can be used for applications such as electronic parts and automobile parts.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08K 5: 098 5: 053 5: 103)

Claims (5)

[Claims] (1) 100 parts by weight of a polyamide resin,
(B) 2 to 20 parts by weight of melamine cyanurate, (c) 0.005 to 3 parts by weight of trialkyl phosphate,
A flame-retardant polyamide composition comprising (d) 0.01 to 5 parts by weight of a higher fatty acid metal salt and (e) 0.01 to 5 parts by weight of a polyhydric alcohol and / or an ester derivative thereof. (2) The trialkyl phosphate (c) is:
Trimethyl phosphate, triethyl phosphate, tri-n phosphate
The flame-retardant polyamide composition according to claim 1, wherein the composition is at least one selected from the group consisting of -propyl and tri-n-butyl phosphate. 3. The flame retardant polyamide composition according to claim 1, wherein (d) the higher fatty acid metal salt is at least one selected from calcium stearate and aluminum stearate. 4. The flame-retardant polyamide composition according to claim 1, wherein (e) the polyhydric alcohol is polyethylene glycol. 5. The method of claim 5, wherein (c) the trialkyl phosphate is trimethyl phosphate, (d) the higher fatty acid metal salt is calcium stearate and / or aluminum stearate,
The flame-retardant polyamide composition according to claim 1, wherein (e) the polyhydric alcohol is polyethylene glycol.