JP2000119515A - Polyamide resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a flame-retardant polyamide resin composition excellent in safety of a gas generated at the time of burning, a thermal properties, a surface appearance and mechanical properties by compounding a polyamide resin, with a salt of a polyphosphoric acid, and a melam (derivative) and a melem (derivative), and an inorganic filler. SOLUTION: This polyamide resin composition is obtained by compounding 100 pts.wt. polyamide composed of xylylenediamine and an α,ω-linear aliphatic dibasic acid, or mixed resin of the polyamide with a polyamide resin such as a mixture of nylon 66 and/or nylon 6, and a thermoplastic resin without the polyamide, e.g. a polyphenylene ether resin, with 1-50 pts.wt. salt composed of a polyphosphoric acid, and a melam (derivative) and a melem (derivative), containing 5-15 wt.% phosphorus, and having <=50 μm average particle diameter, 0.1-20 pts.wt. phosphorus-based flame retardant such as red phosphorus showing <=2 wt.% rate of the weight loss when heated to 250 deg.C in differential thermal analysis, and a condensed phosphoric ester, and 0.1-300 pts.wt. inorganic filler such as a glass fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyamide resin composition, and more particularly, to a flame-retardant polyamide resin composition.

[0002]

2. Description of the Related Art Hitherto, several methods for flame retarding polyamide have been proposed. The most commonly used method is to mix a polyamide with a flame retardant. Halogen-based flame retardants, nitrogen-based compounds, metal-containing compounds, etc. are known as flame retardants.However, halogen-based flame retardants have been questioned for the safety of gas generated during combustion. Flame retardant effect is insufficient.

With respect to nitrogen compounds, for example, JP-A-50-105744, JP-A-53-31759, etc. add a triazine compound such as melamine, cyanuric acid or melamine cyanurate to polyamide. Techniques for improving flame retardancy have been disclosed. However, these methods have the following disadvantages. When an inorganic filler, particularly a fibrous substance such as glass fiber, is blended with polyamide, there is a disadvantage that the fibrous substance exhibits the function of a candle core and the flame retardancy is reduced. In addition, a so-called plate-out phenomenon occurs in which the flame retardant sublimates and adheres to a mold or the like at the time of molding, which results in poor mold release, rough appearance of the molded product, and blooming phenomenon in which a part of the flame retardant precipitates on the surface of the molded product. There are drawbacks such as generation of

[0004] For example, JP-A-53-49054 discloses a flame-retardant composition in which melamine phosphate is blended with polyamide. However, simply blending a salt of phosphoric acid and melamine with polyamide makes it difficult to work during extrusion kneading due to poor compatibility with polyamide, or melamine sublimates during molding to give a molded product appearance. There are disadvantages such as damage.

Furthermore, Japanese Patent Publication No. 61-49342 discloses a flame-retardant composition comprising polyamide and melem or melon (both high-temperature baked melamine). WO 96/09344) discloses a flame-retardant composition obtained by blending a polyamide with a melem-phosphoric acid reaction product. However, none of the above compositions is sufficient in terms of flame retardancy. In addition, the latter composition has a high water-solubility based on phosphate, so that the polyamide composition has high water absorption and dispersibility in polyamide is not sufficient. As a result, strength and elastic modulus may be reduced by water absorption. Further, the hot strength (such as the temperature dependency of the bending strength) may be reduced. Moreover, when water is absorbed,
Since the phosphoric acid reaction product easily migrates to the surface of the molded product, the surface appearance may be deteriorated.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a gas, which is excellent in safety, thermal properties, surface appearance, and mechanical properties, generated during combustion. An object of the present invention is to provide a flame-retardant polyamide resin composition.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems. As a result, melam or melam derivative and melem or melem, which are deammonification reaction products of melamine or melamine derivatives. The present inventors have found that the derivative and the salt of polyphosphoric acid have excellent flame retardancy, and have reached the present invention.

That is, the gist of the present invention is that polyphosphoric acid and a melam or melam derivative and a melem or melem derivative per 100 parts by weight of a resin component with respect to a polyamide resin or a mixed resin composed of a polyamide resin and a thermoplastic resin other than the polyamide resin. And 1 to 50 parts by weight of a salt consisting of:

Hereinafter, the present invention will be described in detail. The resin component in the present invention is a polyamide resin or a mixed resin composed of a polyamide resin and a thermoplastic resin other than the polyamide resin.

As the above polyamide resin, for example,
Nylon 6, Nylon 66, Nylon 69, Nylon 6
10, nylon 612, nylon 12, polyamide resins (hereinafter also referred to as MX nylon) obtained from xylylenediamine and α, ω-linear aliphatic dibasic acid, and mixtures thereof.

In the present invention, MX nylon or a mixed polyamide resin thereof with nylon 66 and / or nylon 6 is preferable, and a mixed polyamide resin of MX nylon and nylon 66 is particularly preferable. In a mixed polyamide resin of MX nylon and nylon 66 and / or nylon 6, the mixing ratio of nylon 66 and / or nylon 6 to 100 parts by weight of MX nylon is 0.1 to 10%.
0 parts by weight, preferably 0.1 to 80 parts by weight.

Examples of the thermoplastic resin other than the above polyamide resin include polystyrene resin, ABS resin, and A
ES resin, AS resin, olefin resin, methacrylic resin, polycarbonate resin, polyacetal resin, polyphenylene ether resin (PPE resin), modified PPE resin, polyester resin, polysulfone resin, polyimide resin, polyphenylene sulfide resin, polyarylate resin, polyether Examples thereof include a sulfone resin, a polyether ketone resin, a polyether ether ketone resin, a polyester carbonate resin, an amorphous polyamide resin, a liquid crystal polymer, and an alloy resin composition comprising two or more of these resins. In the present invention, a polyphenylene ether resin (PPE resin) is preferred.

In the mixed resin comprising a polyamide resin and a thermoplastic resin other than the polyamide resin, the ratio (weight ratio) of the polyamide resin to the thermoplastic resin other than the polyamide resin is usually 99/1 to 1/99, preferably 90/99. / 1
0-10 / 90, more preferably 70 / 30-30 / 7
0.

The above-mentioned polyphenylene ether resin is a resin having a structural unit represented by the following general formula (I) in the main chain, and may be any of a homopolymer, a copolymer and a graft polymer. In the general formula (I), R ¹ is a lower alkyl group having 1 to 3 carbon atoms, and R ² and R ³ are a hydrogen atom or a lower alkyl group having 1 to 3 carbon atoms. n shows the number of repeating units.

[0015]

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Specific examples of the polyphenylene ether resin include poly (2,6-dimethyl-1,4-phenylene)
Ether, poly (2,6-diethyl-1,4-phenylene) ether, poly (2,6-dipropyl-1,4-phenylene) ether, poly (2-methyl-6-ethyl-)
1,4-phenylene) ether, poly (2-methyl-6)
-Propyl-1,4-phenylene) ether and the like.

In the present invention, a poly (2,6-dimethyl-1,4-phenylene) ether, a 2,6 dimethylphenol / 2,3,6-trimethylphenol copolymer and a graft copolymer obtained by grafting styrene to these are used. Polymers are preferred, and polyphenylene ether resins with improved compatibility (hereinafter sometimes referred to as modified PPE) are more preferred. The modified PPE is obtained by reacting PPE with an unsaturated carboxylic acid or an acid anhydride thereof.

When an acid anhydride of an unsaturated carboxylic acid is used for the modification of the PPE, the modified PPE is obtained by reacting the acid anhydride of the unsaturated carboxylic acid and the PPE in a melt-mixed state without a catalyst. Comes out. In this case, examples of the melt mixing means include a kneader, a Banbury mixer, and an extruder, but an extruder is preferable from the viewpoint of operability. Examples of the acid anhydride of the unsaturated aliphatic carboxylic acid include maleic anhydride, itaconic anhydride, citraconic anhydride and the like, and maleic anhydride is particularly preferable.

The proportion of the acid anhydride required for the modification of the PPE is usually 0.01 to 10 parts by weight, preferably 0.1 to 3 parts by weight, more preferably 0.1 to 1 part by weight, per 100 parts by weight of the PPE. Parts by weight. The use ratio of acid anhydride is 0.0
When the amount is less than 1 part by weight, the effect of improving the compatibility between PPE and nylon is small, so that it is difficult to obtain a tough composition,
If it exceeds 10 parts by weight, excess acid anhydride is thermally decomposed, which causes practical inconveniences such as reduced heat resistance and poor appearance.

When an unsaturated aliphatic carboxylic acid is used for modifying PPE, a radical generator such as benzoyl peroxide, dicumyl peroxide or cumene hydroperoxide can be used as a catalyst, if necessary. The usage ratio of the unsaturated carboxylic acid necessary for the modification of PPE is usually 0.01 to 10 parts by weight based on 100 parts by weight of PPE.

In the present invention, the salt comprising polyphosphoric acid and melam or a melam derivative and melem or a melem derivative (hereinafter abbreviated as “polyphosphate”) are represented by the following general formulas (II) to (IV). Compounds to be used. In the general formula (II), M represents a compound (melam or a melam derivative) represented by the general formula (III) and a compound (melem or a melem derivative) represented by the general formula (IV), and n is 2 or more. Represents a number. In the general formulas (III) and (IV), R
⁴ represents a hydrogen atom, a cyano group or a guanyl group. Desirable R ⁴ is a hydrogen atom.

[0022]

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The above polyphosphate can be obtained, for example, by baking a salt obtained by a neutralization reaction between phosphoric acid and melamine or a melamine derivative at 350 to 500 ° C. for several hours. At this time, it is possible to obtain a salt of a mixture in which the ratio of melam and melem differs depending on the firing temperature and the firing time. Further, at this time, depending on the firing time and the firing temperature, the deammonification reaction of melem partially proceeds, and a salt composed of polyphosphoric acid and melon may be generated. If the quantity
It may be contained in polyphosphate. All products are white solids. Usually, it is used by pulverizing it into fine powder.

The phosphorus content in the polyphosphate is not particularly limited, but is preferably 5 to 15% by weight. When the phosphorus content is less than 5% by weight, the flame retardancy tends to decrease, and when it exceeds 15% by weight, the hygroscopicity tends to increase. A more preferred range for the phosphorus content is 7-12% by weight.

The average particle size of the polyphosphate is usually 50 μm.
m, preferably 0.1 to 30 μm. If the average particle size exceeds 50 μm, the dispersibility in the polyamide resin tends to decrease, and the appearance of the molded article tends to deteriorate.

Specific examples of the salt comprising polyphosphoric acid and melam or a melam derivative include, for example, melam polyphosphate, cyanomelam polyphosphate, guanyl melam polyphosphate and the like. Specific examples of salts comprising polyphosphoric acid and melem or melem derivatives,
For example, melem polyphosphate, cyanomelem polyphosphate, guanyl melem polyphosphate and the like can be mentioned. In the present invention, a mixed salt of melam polyphosphate and melem polyphosphate, which is relatively easy to produce industrially, is preferred.

The weight ratio of melam or a melam derivative to melem or a melem derivative is not particularly limited.
Range less than 0/10 and 5/95 or more, preferably 75/95
It is in the range of 25-5 / 95. In particular, the range of 50/25 to 5/95 is preferable from the viewpoint of ease of industrial production.

In general, melam or melam derivatives and melem or melem derivatives have better thermal stability than melamine, and have a decomposition temperature of 450 ° C. or more by differential thermal analysis. Therefore, it is difficult to sublimate even at the molding temperature of the polyamide resin.

Examples of the phosphoric acid used for producing the polyphosphate include orthophosphoric acid, phosphorous acid, hypophosphorous acid and the like. In the present invention, orthophosphoric acid that can be industrially mass-produced is preferable. Further, in order to improve the solubility of orthophosphoric acid in water and the hygroscopicity, it is preferable to convert a part of orthophosphoric acid into a phosphoric acid such as pyrophosphoric acid or metaphosphoric acid.

In the polyamide resin composition of the present invention,
The compounding amount of the polyphosphate is 1 to 50 parts by weight, preferably 2 to 40 parts by weight, more preferably 3 to 30 parts by weight, per 100 parts by weight of the resin component. If the amount of the polyphosphate is less than 1 part by weight, the flame retardancy is insufficient,
If it exceeds 50 parts by weight, the mechanical properties are reduced.

In the present invention, a small amount of a phosphorus-based flame retardant (hereinafter simply abbreviated as "phosphorous-based flame retardant") whose weight loss on heating by differential thermal analysis is not more than 2% by weight at 250.degree.
It is preferable to use them together because they exhibit excellent effects in terms of flame retardancy, mechanical properties and moldability. The above weight loss rate under heating is a physical property value defined from the viewpoint of low gas property and low blooming property during molding. The type of such a phosphorus-based flame retardant is selected from organic phosphorus-containing compounds, red phosphorus, phosphazene-based compounds, ammonium polyphosphate, and the like.

Examples of the organic phosphoric acid-containing compound include phosphates typified by triphenyl phosphate and phosphites typified by triphenyl phosphite. Specific examples include triphenyl phosphate,
Phosphate esters such as trithiophenyl phosphate, trixylenyl phosphate, hydroquinone bis (diphenyl phosphate), resorcinol bis (diphenyl phosphate), and condensed phosphoric esters such as phenylresorcinol polyphosphate and resorcinol polyphosphate. .

Red phosphorus is one allotrope of phosphorus and is generally an amorphous, red-brown solid. The density is 2.
It is about 1 to 2.3. Red phosphorus is obtained, for example, by heating yellow phosphorus in an inert gas.

As the phosphazene compound, for example,
Any phosphenitrile derivative represented by the following general formula (III) may be used, and examples thereof include propoxyphosphazene oligomers and phenylphosphazene oligomers. m shows the number of repeating units.

[0035]

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In the present invention, ammonium polyphosphate, red phosphorus, and condensed phosphoric acid esters are preferable, and red phosphorus and condensed phosphoric acid ester are particularly preferable in terms of heat resistance and availability. Two or more phosphorus-based flame retardants may be used in combination.

In the polyamide resin composition of the present invention,
The mixing ratio of the phosphorus-based flame retardant is usually 0.1 to 20 parts by weight, preferably 0.2 to 100 parts by weight, per 100 parts by weight of the resin component.
To 15 parts by weight, more preferably 0.3 to 10 parts by weight. When the compounding ratio of the phosphorus-based flame retardant is less than 0.1 part by weight, the flame retardant effect becomes small, and when it exceeds 20 parts by weight, coloring and blooming of the molded article become remarkable.

In the present invention, various inorganic fillers can be used. The shape of the inorganic filler is not particularly limited, and may be any of a fiber shape, a plate shape, a needle shape, a spherical shape, and a powder. Types of inorganic fillers include glass fiber,
Carbon fiber, talc, mica, glass flake, wollastonite, potassium titanate whisker, magnesium sulfate, sepiolite, zonolite, aluminum borate whisker, glass beads, balloon, calcium carbonate, silica, kaolin, clay, titanium oxide, barium sulfate , Zinc oxide, magnesium hydroxide and the like.
These can be used alone or as a mixture of two or more. In the present invention, glass fibers, calcium carbonate or aluminum borate whiskers are preferred.

In the polyamide resin composition of the present invention,
The compounding amount of the inorganic filler is 100 parts by weight of the resin component,
It is usually 0.1 to 300 parts by weight, preferably 5 to 300 parts by weight, more preferably 10 to 250 parts by weight, particularly preferably 50 to 150 parts by weight. The amount of the inorganic filler is 3
If the amount is more than 00 parts by weight, the workability is reduced.

In the polyamide resin composition of the present invention, various additives generally used for polymer materials, for example, ultraviolet absorbers, stabilizers, face dyes, release agents, lubricants,
A nucleating agent, a weather resistance improving agent and the like can be appropriately compounded.

The preparation of the polyamide resin composition of the present invention comprises:
This can be done in the usual way. For example, conventional equipment,
For example, using a vent-type extruder or a device similar thereto, the polyamide resin, a thermoplastic resin other than the polyamide resin, and if necessary, an inorganic filler and various additives are melt-kneaded in an arbitrary order.

[0042]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. The raw materials used in the examples and comparative examples are as follows.

(1) Polymethaxylylene adipamide (hereinafter referred to as "nylon MXD6"): Mitsubishi Gas Chemical Co., Ltd.
And a relative viscosity of 2.14 (25% in 98% sulfuric acid as a solvent).
(2) Nylon 66: relative viscosity 2.95 (3) Nylon 6: relative viscosity 2.20

(4) Maleic anhydride-modified PPE: PPE
To 5 kg (manufactured by Mitsubishi Gas Chemical Co., Ltd., intrinsic viscosity 4.45), 50 g of maleic anhydride was added, mixed with a super mixer for 3 minutes, and then kneaded with a twin-screw extruder at 300 ° C. while heating and melting. Prepared. (5) Glass fiber: length 3
mm chopped strand (“CS03-JAFT2” manufactured by Asahi Fiberglass Co., Ltd.)

(6) Calcium carbonate (“NS-100” manufactured by Nitto Powder Chemical Co., Ltd.)

(7) (Melam / Melem) described in the following table
Polyphosphate mixture (Nissan Chemical Industries, Ltd.)

[0047]

[Table 1]

(8) Melem (manufactured by Nissan Chemical Industries, Ltd.) (9) Red phosphorus (Hishigard TP manufactured by Nippon Chemical Industry Co., Ltd.)
−10 ”) (10) Condensed phosphate ester (“ P ”manufactured by Daihachi Chemical Industry Co., Ltd.)
X-200 ”) (11) Melamine cyanurate (“ M ”manufactured by Nissan Chemical Industries, Ltd.)
C-440 ") (12) Magnesium hydroxide (" Kisuma 5E "manufactured by Kyowa Chemical Co., Ltd.)

In Examples and Comparative Examples, bending strength,
Tests for flammability and mold contamination were performed as follows.

(1) Flame retardancy: A test was conducted in accordance with Subject 94 (UL-94) standard set by Underwriters Laboratories, USA. A test piece (length 5 inches, width 1/2 inch, thickness 1/16 inch) was formed from the resin composition as follows. That is, molding was performed using an injection molding machine under the conditions of a resin temperature of 260 ° C. and a mold temperature of 130 ° C.

(2) Flexural strength: Measured according to ASTM D790. Test piece (5 inch long, 1/2 inch wide,
Molding was performed in the same manner as described above.

(3) Mold contamination test: injection primary pressure 500 kgf / c
m ² , injection speed 20 mm / s, holding pressure 0 kgf / cm ² , injection time 3 seconds, molding temperature 270 ° C, mold temperature 130 ° C, cooling time 8 seconds. 1
00 shot molding was performed, and the mold surface after the molding was visually observed. The surface condition was evaluated in the following four stages.

[0053]

[Table 2] ：: Almost no mold contamination is observed. ○: Slight mold contamination is observed. △: Die contamination is observed. X: Die contamination is noticeably observed.

Examples 1 to 18 and Comparative Examples 1 to 12 The components shown in Tables 3 to 9 were weighed in the amounts shown in the same table, mixed by a tumbler, and melt-kneaded at 270 ° C. by a vent type extruder. It was extruded into a string, cooled in a water bath, cut and dried to form a pellet. Table 3 shows the evaluation results of the obtained materials.
It is shown in FIG.

[0055]

[Table 3]

[0056]

[Table 4]

[0057]

[Table 5]

[0058]

[Table 6]

[0059]

[Table 7]

[0060]

[Table 8]

[0061]

[Table 9]

[0062]

Industrial Applicability The polyamide resin composition of the present invention has excellent thermal properties, surface appearance, mechanical properties, and flame retardancy in addition to the excellent properties inherent to polyamide, and furthermore, the gas generated during combustion. It has excellent safety and can be used for various molded products. Moreover, the polyamide resin composition of the present invention,
In particular, it is excellent in bending strength, flexural modulus, etc., and has mechanical properties that can be substituted for metal, so it can be used for mechanical parts such as OA equipment that requires high mechanical properties and is extremely useful. . Further, the polyamide resin composition of the present invention is excellent in mold contamination during molding, and is also excellent in moldability, which is advantageous for producing various molded products.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C08K 7/08 C08K 7/08 7/14 7/14 C08L 71/12 C08L 71/12 101/00 101/00 (72 ) Inventor Noriyoshi Watanabe 5-6-2 Higashi-Hachiman, Hiratsuka-shi, Kanagawa F-term in the Technology Center of Mitsubishi Engineering-Plastics Co., Ltd. (Reference) CM04X CN01X CN03X CQ013 DA018 DA057 DE078 DE088 DE108 DE138 DE188 DG048 DH056 DH059 DJ008 DJ018 DJ038 DJ048 DJ058 DK008 DL008 EU186 EW047 EW157 FA018 FA048 FA068 FA088 FA108 FA118 FD018 FD133 FD136 FD137 FD139

Claims (9)

[Claims] A salt comprising polyphosphoric acid and a melam or melam derivative and a salt of melem or a melem derivative per 100 parts by weight of a resin component with respect to a polyamide resin or a mixed resin comprising a polyamide resin and a thermoplastic resin other than the polyamide resin. A polyamide resin composition characterized by blending parts by weight. 2. The polyamide resin according to claim 1, wherein the polyamide resin is a polyamide resin obtained from xylylenediamine and α, ω-linear aliphatic dibasic acid, or a mixed polyamide resin thereof with nylon 66 and / or nylon 6. The polyamide resin composition according to the above. 3. The polyamide resin composition according to claim 1, wherein the thermoplastic resin other than the polyamide resin is a polyphenylene ether resin. 4. The polyamide resin composition according to claim 1, wherein the phosphorus content of the salt comprising polyphosphoric acid and melam or a melam derivative and melem or a melem derivative is 5 to 15% by weight. 5. The polyamide resin composition according to claim 1, wherein the salt comprising polyphosphoric acid and melam or a melam derivative and a salt composed of melem or a melem derivative have an average particle size of 50 μm or less. 6. The resin composition according to claim 1, further comprising 0.1 to 20 parts by weight of a phosphorus-based flame retardant having a heating weight reduction rate by differential thermal analysis of not more than 2% by weight at 250 ° C. per 100 parts by weight of the resin component. Item 6. The polyamide resin composition according to any one of Items 1 to 5. 7. The heating weight loss rate by differential thermal analysis is 25.
The polyamide resin composition according to claim 6, wherein the phosphorus-based flame retardant that is 2% by weight or less at 0 ° C is red phosphorus or a condensed phosphate ester. 8. The polyamide resin composition according to claim 1, further comprising 0.1 to 300 parts by weight of an inorganic filler per 100 parts by weight of the resin component. 9. The inorganic filler is glass fiber, calcium carbonate or aluminum borate whisker.
The polyamide resin composition according to the above.