JPH0741598A - Flame retardant for thermoplastic resin - Google Patents

Abstract

PURPOSE:To impact excellent flame retardancy to a thermoplastic resin without detriment to the resin and without any fear of the generation of noxious gases by adding a specified polyphosphonic acid amide to the resin. CONSTITUTION:An m-xylenediamine-type polyphenylphosphonic acid amide of the formula (wherein n is an integer of 3-150) is added to a thermoplastic resin. A preferred amide is one having a heating loss of 2wt.% of below at 300 deg.C when it is heated at a temperature rise rate of 20 deg.C/min in a nitrogen atmosphere in a thermobalance. A preferred thermoplastic resin is one which comprises at least one resin selected from among polyester, polyamide, polycarbonate and polyphenylene oxide.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a halogen-free flame retardant effective for thermoplastic resins. More specifically, the present invention relates to a non-halogen flame retardant capable of imparting a high degree of flame retardance without generating harmful gas or corrosive gas and without impairing the mechanical properties and heat resistance of the thermoplastic resin.

[0002]

2. Description of the Related Art Thermoplastic resins are used as injection molding materials in a wide range of fields such as mechanical parts, electric parts and automobile parts. Among them, a series of resins called engineering plastics have mechanical properties, Since it is particularly excellent in thermal properties and electrical properties, it is being widely used for electric / electronic parts, machine / mechanical parts, automobile parts, etc. that require high strength and high heat resistance. Also,
Since these engineering plastics have higher flame retardancy than other general-purpose resins, they are also widely used in fields requiring flame retardancy. However, in recent years, the level of flame retardancy required for plastic materials has become strict particularly in the use of electric / electronic parts such as televisions, and higher flame retardancy is also required for engineering plastics.

A common method for imparting flame retardancy to a thermoplastic resin is to compound a halogen-based organic compound as a flame retardant and an antimony compound as a flame retardant aid into the resin. However, this method produces a very large amount of smoke during combustion, and halogen is released during processing and use of molded products to generate corrosive hydrogen halide gas, which causes corrosion of the mold and metal contact. It has the problem of becoming a source of pollution. Further, since the antimony compound, which is a flame retardant auxiliary agent that is usually used together to enhance the effect of the flame retardant, is a foreign substance to the resin, it has a drawback that it causes deterioration of mechanical properties. Further, it has recently been pointed out that toxic brominated dibenzodioxin or brominated dibenzofuran is generated during processing or combustion of a resin containing some brominated flame retardants.

Therefore, in recent years, it has been strongly desired to use a flame retardant containing no halogen in order to overcome the drawbacks of these halogen flame retardants.

Red phosphorus is the most common non-halogen flame retardant for thermoplastic resins and has already been disclosed in JP-A-58-58.
The technology is disclosed in Japanese Patent Laid-Open No. 196259 and Japanese Patent Laid-Open No. 59-24752.

As a non-halogen flame retardant for polyamide, for example, magnesium hydroxide (JP-A-54-83)
952, JP-A-54-131645, and melamine cyanurate (JP-A-53-31759).
As a non-halogen flame retardant for polycarbonate such as JP-A-54-91558), organic sulfonates (JP-A-50-98539 and JP-A-50-98540) are used.
No.), sulfimidate (Japanese Patent Publication No. 01-22304).
As a non-halogen flame retardant for polyphenylene oxide, phosphonate compounds and ammonium polyphosphate (JP-A-52-86449), phosphate compounds and antimony trioxide (JP-A-49-32947).
As a non-halogen flame retardant for polyesters, etc., polyphosphonates (US Pat. No. 3719727)
Etc. are known. Further, in the case of polyester, polyphosphonic acid amide (Japanese Patent Application Laid-Open No. 50-15 / 1975) is used for fibers.
9540) and the like are also known.

[0007]

However, the above-mentioned prior art has the following problems.

In the case of the flame-retardant technique of a thermoplastic resin using red phosphorus, (1) since red phosphorus is reddish brown, the resin is colored reddish brown by the blending of red phosphorus, making coloring impossible. Become.

(2) Mechanical properties by mixing red phosphorus,
In particular, the toughness is remarkably reduced, and it cannot be used in a field requiring impact resistance.

(3) In the blend of red phosphorus, toxic and corrosive phosphine gas is generated during thermal processing or incineration. Generation of phosphine gas not only worsens the working environment, but also causes mold fouling. In order to suppress this, a method of coating red phosphorus with a coating agent or impregnating red phosphorus powder with a thermosetting resin has been devised, but the generation of phosphine gas has not been completely suppressed.

Further, in the case of magnesium hydroxide, melamine isocyanurate, phosphonate compound and ammonium polyphosphate, phosphate compound and antimony trioxide, the mechanical properties of the thermoplastic resin, particularly toughness, are lowered, and organic sulfonate and sulfimidic acid are used. In the case of salt and polyphosphonate, the hydrolysis resistance is lowered. Further, the polyphosphonic acid amide proposed for polyester fibers also has a problem that when it is used for molded articles, the resin is colored and mechanical properties are deteriorated.

As described above, the conventional flame-retardant technology has not been able to impart a high degree of flame-retardancy to the thermoplastic resin without impairing the color tone and mechanical properties. Also, from the viewpoint of safety, no satisfactory flame retardant technology has been found yet.

Therefore, the object of the present invention is to develop a non-halogen flame retardant capable of imparting a high degree of flame retardancy without impairing the mechanical properties and color tone of the thermoplastic resin.

[0014]

The inventors of the present invention have made extensive studies in view of the above situation, and as a result, polyphosphonamide having an m-xylylenediamine skeleton has high flame retardancy-imparting performance for thermoplastic resins. The present invention has been reached and the present invention has been reached.

That is, the present invention is a flame retardant for a thermoplastic resin having a structure represented by the following formula (1).

[0016]

[Chemical 2] (However, in the above formula, n represents an integer of 3 to 150).

The thermoplastic resin used in the present invention means a resin which exhibits fluidity by heating and can be shaped by this. Specific examples include polyesters such as PBT (polybutylene terephthalate) and PET (polyethylene terephthalate), polycarbonates,
PPO (polyphenylene oxide or polyphenylene ether), nylon 6, nylon 66, nylon 12
Polyamide such as, polyacetal, polyethylene, polypropylene, polybutadiene, polyacrylonitrile, polystyrene, polyolefin such as polymethylmethacrylate, polyethylene oxide, polyalkylene oxide such as polytetramethylene oxide, thermoplastic polyurethane, phenoxy resin and the like. May be a homopolymer or a copolymer. Further, it may be a mixture of two or more of these thermoplastic resins. Among these thermoplastic resins, polyesters, polycarbonates, polyphenylene oxides, polyamides, copolymers thereof, and mixtures thereof are preferably used.

Further, the thermoplastic resin used in the present invention includes phosphorus-based, sulfur-based, hindered phenol-based antioxidants, heat stabilizers, ultraviolet absorbers, lubricants, release agents, and dyes / pigments. It may contain one or more kinds of usual additives such as a coloring agent. Further, glass fibers, carbon fibers, metal fibers, aramid fibers, asbestos, potassium titanate whiskers, wollastonite, glass flakes, glass beads, talc, mica, clay, calcium carbonate, barium sulfate, titanium oxide, as long as the thermoplasticity is not impaired. And fibrous and / or granular fillers such as aluminum oxide.

The flame retardant of the present invention is a polyphosphonic acid amide represented by the above formula (1), and the production method thereof is not particularly limited, but the following three types are representative examples. You can

A method of reacting m-xylylenediamine and phenylphosphonic acid dihalide in a solvent such as chloroform or tetrahydrofuran in the presence of a hydrogen halide scavenger.

A method in which m-xylylenediamine and phenyldichlorophosphine are reacted in a solvent such as chloroform or tetrahydrofuran in the presence of a hydrogen halide scavenger, and then oxidized using an oxidizing agent such as hydrogen peroxide.

A method in which m-xylylenediamine and phosphonic acid diamide are reacted in the presence or absence of a catalyst in a solvent or without a solvent.

As the phosphorus component used in the above-mentioned production method, phenylphosphonic acid dichloride, phenylphosphonic acid dibromide, phenylphosphonic acid difluoride can be used. Further, specific examples of the phosphonic acid diamide used in the production method include phenylphosphonic acid diamide, N, N′-dimethyl-phenylphosphonic acid diamide, N, N ′, N ″, N ′ ″-tetramethyl-
Phenylphosphonic acid diamide, phenylphosphonic acid dianilide and the like can be used.

Regarding the degree of polymerization of the phosphonic acid amide, the number average degree of polymerization, that is, n in the formula (1) is 3
It is necessary to be ~ 150, preferably 4 ~ 12
0, more preferably 5 to 100. When n is less than 3, volatility is high and volatilization occurs during heat processing or the like, and bleeding on the surface of the molded product may impair the surface appearance, which is not preferable. Further, when n exceeds 150, the dispersibility in the thermoplastic resin decreases, and not only the flame retardancy but also the mechanical properties are impaired, which is not preferable.

The flame retardant of the present invention is used in an amount of 0.5 to 100 parts by weight, preferably 1 to 80 parts by weight, more preferably 5 to 50 parts by weight, based on 100 parts by weight of the thermoplastic resin. If the addition amount is less than 0.5 parts by weight, the flame retardant effect is not sufficient, and if it exceeds 100 parts by weight, the mechanical properties of the molded product deteriorate, which is not preferable.

Further, when unreacted monomers and the like remain in the m-xylylenediamine type polyphosphonic acid amide flame retardant of the present invention, a bad odor during compounding, mold contamination during injection molding, gas generation from a molded article, molding This may be accompanied by coloring of the product. To prevent these, when the m-xylylenediamine-type polyphosphonic acid amide used is heated in a thermobalance under a nitrogen stream and heated at a rate of 20 ° C./min, the weight loss at 300 ° C. is 2% by weight or less. It is particularly preferable to use one. Further, as a method for purifying the polyphosphonic acid amide, a method of washing a powdery substance obtained by polymerization with water or an organic solvent, a method of dissolving the polymer in an organic solvent and then performing reprecipitation purification by adding a poor solvent, etc. Although it can be adopted, a method by reprecipitation purification is more preferable for purification to the above-mentioned level.

The flame retardant of the present invention is usually blended with a thermoplastic resin by a known method. For example, a method of melt mixing a thermoplastic resin, polyphosphonic acid amide in an extruder,
Alternatively, after mechanically mixing the particles uniformly,
Examples include a method of molding at the same time as mixing with an injection molding machine.

[0028]

The present invention will be described in more detail with reference to the following examples. Here, all parts are parts by weight. The measuring method of each characteristic is as follows.

(1) Mechanical Properties ASTM dumbbell test pieces obtained by injection molding
Tensile yield strength and breaking elongation were measured according to D-638.

(2) Flammability 5 inches long, 0.5 inches wide, and 1 / thick from pellets
A 32-inch test piece was manufactured and used by Underwriters Laboratories, USA
The flame retardancy was evaluated according to the evaluation standard stipulated in UL94 of atories.

The flame retardancy level is V-0>V-1>V-2>
It decreases in the order of HB.

(3) Color tone A dumbbell test piece obtained by injection molding was used for visual evaluation.

Reference Example 1 Equimolar amounts of m-xylylenediamine and phenylphosphonic acid dichloride and 2.1 times mol of triethylamine were heated to reflux in chloroform at room temperature for 6 hours. The obtained reaction liquid was concentrated by an evaporator, dissolved in a large amount of methanol, and then poured into water. The formed precipitate was collected by suction filtration, washed with a large amount of water, and then dried in a vacuum dryer. Yield 96%. The m-xylylenediamine type polyphosphonic acid amide thus obtained is used as a flame retardant A. In addition, in flame balance of flame retardant A 3
The weight loss rate at 00 ° C. was 2.2%.

Further, the flame retardant A was dissolved in a small amount of N-methylpyrrolidone and put into a large amount of agitated water / methanol mixture for reprecipitation purification. This purified product is flame retardant B
And Heat loss rate of flame retardant B in thermobalance is 0.6%
Became.

Reference Example 2 Equimolar amounts of m-xylylenediamine and phenylphosphonic acid diamide were gradually heated and agitated from 100 ° C. in the presence of magnesium oxide in a nitrogen atmosphere, and 250 minutes after 3 hours.
The temperature was raised to ° C. Along the way, when the amount of generated ammonia increased, a nitrogen stream was passed to remove the ammonia.

After cooling the reaction mixture to room temperature, NMP
Was added and dissolved, and the insoluble matter was removed by filtration. The filtrate was poured into a large amount of water, and the formed precipitate was collected by suction filtration. After washing with a large amount of water, it was dried in a vacuum dryer. Yield 84%. The m-xylylenediamine type polyphosphonic acid amide thus obtained is used as a flame retardant C. In addition, the weight loss rate of the flame retardant C in the thermobalance at 300 ° C. was 2.5%.

Reference Example 3 m was the same as flame retardant C except that an equimolar amount of m-phenylenediamine was used in place of m-xylylenediamine.
-Phenylenediamine type polyphosphonic acid amide was synthesized and purified in the same manner as in the case of the flame retardant B. This is designated as flame retardant D. In addition, 300 ℃ in thermobalance of flame retardant D
The weight loss rate was 3.9%.

Examples 1-18, Comparative Examples 1-25 Intrinsic viscosity 0.85 (o-chlorophenol solution, 25
C) PBT, relative viscosity 2.70 (1% concentrated sulfuric acid solution, 2
5 ° C) Nylon 6 and Relative Viscosity 2.50 Nylon 6
6, logarithmic viscosity 0.56 (0.5% methylene chloride solution, 2
Bisphenol A type polycarbonate (0 ° C), poly (2,2) with an intrinsic viscosity of 0.53 (chloroform solution, 25 ° C)
6-Dimethyl-1,4-phenylene) oxide and GPC
Mixture with polystyrene having a weight-average molecular weight of 435,000 measured by the method (mixing weight ratio 60:40), each 100
Mixing parts by weight of m-xylylenediamine type polyphosphonic acid amides A to C, m-phenylenediamine type polyphosphonic acid amide D, red phosphorus and other additives,
Melt extrusion was performed using a 30 mmΦ twin-screw extruder. The pellets obtained are dried and then injection molded according to ASTM D-63.
A tensile test piece specified in No. 8 was produced. Moreover, the flame-retardant evaluation test piece based on UL94 was similarly produced. The melt extrusion, pellet drying, and injection molding conditions for each resin are shown below.

PBT: Extrusion: 250-290 ° C./150
rpm Drying: 110 ° C./12 hours Molding: 250 to 290 ° C./mold 80 ° C.

Nylon 6, Nylon 66: Extrusion: 250
~ 300 ° C / 150 rpm Drying: 100 ° C / 24 hours Molding: 250-300 ° C / mold 80 ° C.

Polycarbonate: Extrusion 260-320 ° C.
/ 75 rpm Drying: 120 ° C./12 hours Molding: 260-320 ° C./die 110 ° C.

Mixture of polyphenylene oxide and polystyrene: Extrusion: 240-310 ° C / 70 rpm Drying: 110 ° C / 4 hours Molding: 240-320 ° C / mold 90 ° C.

Tables 1 to 1 show the flame retardance, mechanical properties, color tone of molded products, and the presence or absence of phosphine odor during heat processing of each sample.
It shows collectively in 4.

In the table, GF represents glass fiber.
PPO represents a mixture of poly (2,6-dimethyl-1,4-phenylene) oxide and polystyrene (mixing weight ratio 60:40). The addition amount of each component is shown in all parts, but for the m-xylylenediamine type polyphosphonic acid amide and the m-phenylenediamine type polyphosphonic acid amide, in addition to the number of added parts, the weight% of phosphorus element in the whole composition Is also shown.

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

[Table 3]

[0048]

[Table 4]

Examples 1-3, 7-9, 13, 15, 17
From the evaluation results of Comparative Examples 1, 6, 11, 16 and 21, P
It can be seen that excellent flame retardancy can be imparted by blending m-xylylenediamine type polyphosphonic acid amide with BT, nylon, polycarbonate, and polyphenylene oxide resin. Further, in Comparative Examples 3, 8, 13, 18, and 23 which are flame-retarded with red phosphorus, it can be seen that the mechanical properties and color tone are deteriorated, and phosphine gas is generated during the heat processing. High flame retardancy is also obtained in Comparative Examples 5, 10, 15, 20, and 25, which are flame-retarded with m-phenylenediamine type polyphosphonic acid amide (flame retardant D), but m-xylylenediamine Mechanical properties are slightly deteriorated and the color tone is reddish brown as compared with the case of using the polyphosphonic acid amide.

Examples 4-6, 10-12, 14, 16,
From 18 and Comparative Examples 2, 7, 12, 17, and 22, it is understood that the m-xylylenediamine type polyphosphonic acid amide has excellent flame retardancy-imparting performance even in the presence of glass fibers. On the other hand, Comparative Examples 4, 9, 14, 19, 24 containing red phosphorus
Shows that the color tone is deteriorated and phosphine gas is generated during the thermal processing.

As described above, when m-xylylenediamine type polyphosphonic acid amide is used as a flame retardant, a high degree of flame retardancy is achieved without causing deterioration of mechanical properties, deterioration of color tone and generation of phosphine gas. I know that I can do it.

In Examples 1 to 12, m-xylylenediamine type polyphosphonic acid amides having different production methods or different purification levels were used. However, the m-xylylenediamine type polyphosphonic acid having a high purification level and the highest thermal stability was used. When acid amide (flame retardant B) is used, unpurified flame retardant A or flame retardant C
It can be seen that the color tone of the resin is superior to the case of using, but there is no significant difference in flame retardancy and other physical properties.

[0053]

【The invention's effect】

(1) The m-xylylenediamine type polyphosphonic acid amide of the present invention exhibits a higher flame retarding effect than red phosphorus, which is a conventionally known non-halogen flame retardant for thermoplastic resins. Furthermore, it is an excellent flame retardant that does not generate volatile substances during resin processing and does not adversely affect the thermoplastic resin.

(2) The resin composition obtained by blending the m-xylylenediamine type polyphosphonic acid amide of the present invention has not only good flame retardancy but also excellent mechanical properties, melt fluidity and surface appearance. Therefore, it is useful as mechanical parts, electric parts, and automobile parts.

(3) The flame retardant of the present invention does not contain halogen, and there is no fear of generating harmful gas such as hydrogen halide during molding, use, or incineration after disposal.

Claims (3)

[Claims] 1. A flame retardant for a thermoplastic resin having a structure represented by the following formula (1). [Chemical 1] (However, in the above formula, n represents an integer of 3 to 150). 2. The heating weight loss when the temperature is raised at a temperature rising rate of 20 ° C./min in a nitrogen balance in a thermobalance is 2 at the time of heating up to 300 ° C.
The flame retardant for a thermoplastic resin according to claim 1, which is not more than wt%. 3. The flame retardant for a thermoplastic resin according to claim 1, wherein the thermoplastic resin is at least one selected from polyester, polyamide, polycarbonate, and polyphenylene oxide.