JP2008138120A - Method for flameproofing polyamides - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer composition free of a halogen compound and containing polyamides having higher flame retardance as a main component or its molded article. <P>SOLUTION: The flame-retardant polymer composition is obtained by adding an organophosphorus compound and a polyfunctional monomer (PFM) to a polymer alloy of polyamides with a polyphenylene ether resin (referred to also as polyphenylene oxide resin). A molded article containing polyamides having higher flame retardance as a main component is optionally provided by applying a radiation treatment such as γ ray irradiation to its molded article. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for flame-retarding polyamides. More particularly, the present invention relates to a method for flame-retarding polyamides that can provide a polymer composition containing a polyamide having a high degree of flame retardancy as a main component or a molded product thereof without containing halogen compounds.

  Conventionally, as organic flame retardants for organic polymer compounds, organic halogen compounds are attractive because of their great flame retardant effect, wide range of applicable organic polymer compounds, ease of application or low cost, etc. Organic halogen compounds have been widely applied to organic polymer compounds as flame retardants. In addition, there are chlorinated or brominated organic halogen compounds, and various types of compounds are used in large quantities as flame retardants depending on the purpose.

  However, recently, an organic polymer composition containing an organic halogen compound as a flame retardant generates a toxic gas in the event of a fire and causes damage to the human body. Furthermore, it has been clarified that a polymer composition containing a halogen-based flame retardant not only generates acid gas that corrodes the incinerator during incineration, but also discharges harmful substances with high environmental pollution. Yes. Therefore, the industry that uses flame retardants dislikes the use of such halogen flame retardants, and there is an active movement to replace halogen flame retardants with other flame retardants, especially organophosphorus compounds. Recently, it has attracted particular attention. However, while halogen-based flame retardants are effectively applied to a wide range of organic polymer compounds, organophosphorus compounds are effective as flame retardants such as polyphenylene ether resins, phenol resins, polycarbonate resins, epoxy resins or It is limited to organic polymer compounds such as celluloses that are relatively easy to generate carbides during combustion. Therefore, in many organic polymer compounds in which the organophosphorus compound cannot function effectively as a flame retardant, it is still difficult to switch the halogen-based flame retardant to another flame retardant.

Polyamides are excellent in mechanical strength, oil resistance or surface sliding properties, and are widely used as materials for machine parts, electrical equipment parts or daily necessities. Conventionally, combined use of an organic halogen compound and antimony oxide has been common to make these materials highly flame-retardant. Therefore, many attempts have been made to use organophosphorus compounds as flame retardants for polyamides. However, organophosphorus compounds and polyamides are generally poorly miscible, and the surface of the molded product is blooming or bleeding with organophosphorus compounds. In addition to causing the phenomenon of (Bleeding), the flame retardancy effect was not sufficiently obtained. On the other hand, Patent Document 1 discloses a method of making a flame retardant by adding a special organic phosphorus compound to a polymer alloy of polyamides and polyphenylene ether resin (also referred to as polyphenylene oxide resin). ing. According to this method, blooming or bleeding of the organophosphorus compound on the surface of the molded product is prevented, but when the continuous phase of the polymer alloy is a polyamide, a large amount of glass fiber and other inorganic fillers are used. Unless added, the test piece causes flame dripping (also referred to as drip) during the combustion test, and there is a disadvantage that a high degree of flame retardancy cannot be obtained, and there still remains a problem.
International Publication No. 2000/012610 Pamphlet

  An object of the present invention is to provide a polymer composition containing as a main component a polyamide having a high degree of flame retardancy without containing a halogen compound, or a molded product thereof. More specifically, while maintaining various properties such as mechanical strength, oil resistance, or surface slipperiness unique to polyamides, a polymer composition containing polyamides as a main component or a molded product thereof with an organic phosphorus compound. It is to realize advanced flame retardancy.

  According to the present invention, a flame retardant polymer composition is obtained by adding an organophosphorus compound and a polyfunctional monomer to a polymer alloy of polyamides and polyphenylene ether resin. Further, if necessary, the molded product is subjected to radiation treatment such as γ-ray irradiation to provide a molded product mainly composed of polyamides having both high flame retardancy and heat resistance.

  As already mentioned, polyamides have excellent mechanical strength, oil resistance or surface sliding properties, and are widely used as materials for machine parts, electrical equipment parts or daily necessities. Strong demand. Polyamides include 6-nylon, 11-nylon, 12-nylon, 4,6-nylon, 6,6-nylon, 6,10-nylon, polycondensate of m-diaminomethylbenzene and adipic acid (MXD, 6-nylon) or those commonly known as copolymer nylon, and all can be used for the highly flame-retardant method which is the object of the present invention.

  The polyphenylene ether resin is a polymer compound obtained by oxidative polycondensation of 2,6-xylenol in the presence of a catalyst, and has already been widely used as a heat-resistant resin having a high glass transition temperature. Noryl (PPO resin) of General Electric Co., USA and Zylon (PPE resin) of Asahi Kasei Co., Japan are known. It is also known that this resin is imparted with flame retardancy relatively easily by an organic phosphorus compound.

  Regarding the production method of polymer alloys of polyamides and polyphenylene ether resins, JP-A-56-16525, JP-A-56-26913, JP-A-57-36150, JP-A-59-59724, Details are disclosed in Japanese Laid-Open Patent Publication Nos. 59-66452 and 61-204262. Preferred polymer alloys of polyamides and polyphenylene ether resins for the purposes of the present invention are modified with 35 to 70 parts by weight of polyamides and α, β-unsaturated carboxylic acids or acid anhydrides thereof at high temperatures and with high shear forces. It can be prepared by mixing 65 to 30 parts by weight of polyphenylene ether resin. In this mixing range in this method, a polymer alloy is usually formed in which the continuous phase is a polyamide and the dispersed phase is a polyphenylene ether resin. A polymer alloy whose polyamide is a continuous phase retains various properties such as mechanical strength, oil resistance, and surface slipperiness unique to polyamides, and is preferable for the purpose of the present invention.

  Examples of the α, β-unsaturated carboxylic acid or its acid anhydride include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, maleic anhydride, itaconic anhydride or citraconic anhydride. Usually, maleic anhydride is most preferably used economically and effectively, although it can be used for the purpose. A method for producing a polymer alloy of a polyamide and a polyphenylene ether resin modified with an α, β-unsaturated carboxylic acid or its acid anhydride is the same as the method for producing a polymer alloy of the polyamide and the polyphenylene ether resin. The explanation is also found in each publication. The α, β-unsaturated carboxylic acid or anhydride thereof is used in an amount of 0.1 to 2 parts by weight based on 100 parts by weight of the polyphenylene ether resin. In preparing the polyamides and the polyphenylene ether resin, the organic phosphorus compound can be mixed with the polyphenylene ether resin in advance. At this time, the temperature of polymer alloy preparation can be set slightly lower due to the plasticizing effect of the organic phosphorus compound, which is preferable.

  The organophosphorus compounds used for the purposes of the present invention include one phosphorus atom in the molecule such as triphenyl phosphate, tricresyl phosphate, xylenyl diphenyl phosphate, dixylenyl phenyl phosphate or o-zenyl diphenyl phosphate. Examples of more preferable organic phosphorus compounds include compounds having two phosphorus atoms in the molecule represented by the general formula 1.

（式中、Ｒ^１ないしＲ^８は同じであっても異なってもよく、水素原子またはメチル基、Ｘはパラフェニレン基、メタフェニレン基、４，４’−ビフェニレン基、３，３’，５，５’−テトラメチル−４，４’−ビフェニレン基、２，２−ジメチル−１，３−プロピレンビス−４，４’−フェニレン基または２，２−ジメチル−１，３−プロピレン基を表す。）

(Wherein R ¹ to R ⁸ may be the same or different, and are a hydrogen atom or a methyl group, X is a paraphenylene group, a metaphenylene group, a 4,4′-biphenylene group, 3,3 ′, 5, , 5′-tetramethyl-4,4′-biphenylene group, 2,2-dimethyl-1,3-propylenebis-4,4′-phenylene group or 2,2-dimethyl-1,3-propylene group .)

  Regarding some of the organophosphorus compounds represented by the general formula 1, JP-A-5-1079, JP-A-6-306277, JP-A-8-277344, JP-A-8-301844, JP-A-10-45774, Japanese Patent Laid-Open No. 11-343382 or Japanese Patent Laid-Open No. 2004-115763 describes the manufacturing method. These organophosphorus compounds are added in an amount of 2 to 20% by weight, more preferably 4 to 15% by weight, based on the polymer alloy of polyamides and polyphenylene ether resin. When the addition amount of the organophosphorus compound is less than 2% by weight, a sufficient flame retardant effect cannot be obtained, and when it exceeds 20% by weight, the flame retardant effect is sufficient. And the tendency of the organophosphorus compound to bloom or bleed on the surface of the molded article is increased.

  The polyfunctional monomer is an important compound for the purpose of forming a crosslinked structure in the polymer compound during radiation treatment or heat treatment of the organic polymer compound, and is a compound having a plurality of polymerizable unsaturated bonds. Many acrylic, methacrylic or allylic compounds are known. Any of these can be used for the purposes of the present invention. Examples of acrylic polyfunctional monomers include polyethylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, or 1,3,5-triacroylhexahydro-s-triazine. ing. Known methacrylic polyfunctional monomers include ethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, and the like. Examples of the allylic multifunctional monomer include diallyl phthalate, triallyl trimellitate, triallyl phosphate, triallyl isocyanurate, di (diallylamino) phenoxyphosphine oxide, and di (diallylamino) phenylphosphine oxide.

  Among these, the polyfunctional monomer most preferably used for the purpose of the present invention includes 1,3,5-triacroylhexahydro-s-triazine, triallyl isocyanurate or di (diallylamino) phenylphosphine oxide. Is mentioned. The polyfunctional monomer is preferably added in an amount of 0.2 to 5% by weight based on the polymer alloy of polyamides and polyphenylene ether resin. The main purpose of the present invention to use a polyfunctional monomer is to form a crosslinked structure in polyamides, to prevent flame drip during combustion, to provide high flame retardancy, and to polyamides as a main component. This is to further improve the heat resistance of the composition, and if the amount is less than 0.2% by weight, the object cannot be sufficiently achieved. Further, if the amount added exceeds 5% by weight, unless the polymerization inhibitor is added in a large amount, the gelation due to the thermal polymerization reaction often occurs during the kneading or molding of the composition, and the operation is difficult. It is not preferable.

The composition according to the present invention is effective in preventing dripping during combustion by forming some gel components by thermal polymerization of a polyfunctional monomer added at the time of heat preparation by an extruder or at the time of molding. Many. However, in order to most reliably form a crosslinked structure and achieve the object of the present invention, it is desirable to perform a radiation treatment after molding the composition. As the radiation, γ rays are preferable, and Co ⁶⁰ as a radiation source is readily available at present. The irradiation dose is preferably 3 to 100 kGy. If the irradiation dose is less than 3 kGy, a sufficient treatment effect cannot be obtained. On the other hand, if it exceeds 100 kGy, the irradiation beam may destroy the chemical structure of the composition.

  As can be understood from the results of the combustion tests of the examples and comparative examples, compared to the examples, the test pieces of the comparative examples in which the polyfunctional monomer was not added showed a flame drip during the combustion test, and the flame retardant Therefore, the effect of the polyfunctional monomer on the present invention was confirmed. In addition, the polymer alloy of the present invention has polyamide as a continuous phase and maintains the excellent properties of polyamides. Therefore, it has a function as a flame retardant polyamide and is expected to be used in a wide range.

  The basic items of the means for solving the problems of the present invention have been described above. Hereinafter, a simple embodiment of the present invention and various additives according to the purpose of use of the flame-retardant polyamide will be described.

  The composition mainly composed of the polyamide of the present invention can be prepared at once by an extruder having a plurality of inlets. A polyphenylene ether resin and an α, β-unsaturated carboxylic acid or its acid anhydride, particularly maleic anhydride, are charged from the first charging port. Here, a part or all of the organophosphorus compound may be added simultaneously. Polyamides are charged from the second charging port. Here, polyfunctional monomers may be added simultaneously. If there is a third inlet, a part of the organophosphorus compound and the polyfunctional monomer can be added here. Usually, the composition is processed into pellets with a pelletizer.

  Various other additives can be added to the composition containing the basic polyamides of the present invention as a main component and molded. Examples of other additives include polymerization inhibitors, plasticizers, antioxidants, ultraviolet absorbers, ultraviolet stabilizers, antistatic agents, colorants, lubricants, foaming agents, and inorganic fillers.

  A small amount of the polymerization inhibitor is added for the purpose of preventing the polyfunctional monomer from forming an excessive gel component during the process by thermal polymerization. Specific examples thereof include hydroquinone, paramethoxyphenol, para tertiary butyl catechol, and phenothiazine.

  A plasticizer is dissolved in a polyphenylene ether resin and used for the purpose of improving its processability. The organophosphorus compound, which is an essential component of the present invention, also has characteristics as a plasticizer, but if necessary, adipic acid esters, sebacic acid esters, phthalic acid esters, trimellitic acid esters, diethylene glycol esters Triethylene glycol esters, high molecular weight esters or polystyrene are used.

  As the antioxidant, binderd phenol-based, sulfur-based or phosphorus-based ones can be used, but a trace amount of copper compounds is most effective and preferable for polyamides.

  As the ultraviolet absorber, a salicylic acid-based, benzophenone-based, or benzotriazole-based one is used. As the UV stabilizer, hindered amines may be used. Any commercially available antistatic agent, colorant, lubricant or foaming agent is used.

  The addition of an inorganic filler is particularly important since it has the effect of imparting a high degree of rigidity or heat resistance to the composition of the present invention, and includes glass fiber, carbon fiber, anhydrous silicic acid, clay, talc, mica, calcium carbonate, magnesium carbonate, Magnesium hydroxide, aluminum hydroxide, aluminum oxide, zinc oxide, tin oxide or antimony oxide is used. Further, it is known that if the inorganic filler is added in an amount of 20% by weight or more, the flame retardancy of the organic polymer composition is usually improved. In the present invention, the amount of the organophosphorus compound added as a flame retardant The addition is preferable.

  If necessary, the above-mentioned various other additives may be added to the composition based on the basic polyamides of the present invention to prepare a desired molded product according to the purpose of use by an extruder. I can do it.

The radiation treatment of the molded product can be carried out very easily by using Co ⁶⁰ gamma rays. That is, it is realized by passing the molded product under or above the γ-ray source at a speed adjusted so as to obtain irradiation corresponding to a preferable irradiation dose for the molded product. A preferred irradiation dose for the purposes of the present invention is 3 to 100 kGy, more preferably 10 to 60 kGy.

  A composition based on polyamides highly flame-retarded by the method of the present invention or a molded product thereof is excellent in mechanical strength, oil resistance, heat resistance, electrical insulation or surface sliding property, It has suitability as a machine part, electrical equipment part or automobile part.

  Next, in order to further clarify the present invention, specific examples and comparative examples will be described. In the examples, “%” represents wt% and “parts” represents parts by weight. However, the following examples do not limit the present invention.

(Example 1)
Preheat the cylinder and screw of model JSK26, an extruder manufactured by Coperion, Germany, 50 parts of polyphenylene ether resin Zylon S210A manufactured by Asahi Kasei in Japan and 0 maleic anhydride from the first inlet. .3 parts and an organophosphorus compound PX-200 manufactured by Daihachi Chemical Co., Japan (corresponding to a compound in which R ¹ to R ⁸ are all methyl groups and X is a metaphenylene group in the general formula 1). ) Was added 10 parts. From the second inlet, 50 parts of 6,6-nylon PACM3001N manufactured by Asahi Kasei Co., Ltd. and 1 part of the reagent triallyl isocyanurate were added. After the extrusion composition reached a steady state, pellets of the composition were made. Twenty test pieces having a width of 1/2 inch, a length of 5 inches, and a thickness of 1/16 inch were again produced from the pellets with an extruder. Ten of them were tested by the UL-94 combustion test method after one week. The remaining 10 pieces were irradiated with 40 kGy of γ rays from Co ⁶⁰ and tested one week later by the UL-94 combustion test method. During the combustion test, no flame drip was observed regardless of whether the specimen was untreated or treated with γ rays. The results of the combustion test are shown in Table-1. The test piece was confirmed to have a continuous phase of 6,6-nylon by infrared analysis of the surface, and no blooming or bleeding phenomenon of the organophosphorus compound was observed even after one week.

(Comparative Example 1)
Twenty test pieces were prepared in exactly the same manner as in Example 1 except that 1 part of triallyl isocyanurate charged from the second inlet of the extruder in Example 1 was removed. Ten of them were subjected to a combustion test in the same manner as in Example 1 after one week. The remaining 10 pieces were irradiated with 40 kGy of Co ⁶⁰ γ-rays, and tested one week later by the combustion test method. In the burn test, all specimens produced a flame drip. The test results are shown in Table-1. The surface condition of the test piece was the same as that of the test piece of Example 1.

(Example 2)
Ten parts of the organophosphorus compound PX-200 manufactured by Daihachi Chemical Co., Ltd. charged from the first inlet of the extruder in Example 1 were M-104 (R ^{1 in the} general formula 1) manufactured by Matsubara Sangyo Kaisha. To R ⁸ , each of which is a methyl group and X is a 2,2-dimethyl-1,3-propylene group). Twenty test pieces were prepared. Ten of these were tested by the same combustion test method as in Example 1 one week later. The remaining 10 pieces were irradiated with 40 kGy of γ rays from Co ⁶⁰ and tested in the same manner one week later. No flame drip was observed during the combustion test. The results of the combustion test are shown in Table-1. The condition of the surface of the test piece after one week was the same as in Example 1.

(Comparative Example 2)
Twenty test pieces were prepared in the same manner as in Example 2 except that 1 part of triallyl isocyanurate charged from the second charging port in Example 2 was removed. A combustion test was conducted. All the test pieces showed a flame drip when burned. The test results are shown in Table-1.

(Example 3)
From the first inlet of the extruder used in Example 1, 55 parts of the same polyphenylene ether resin, 0.3 parts of maleic anhydride and an organophosphorus compound made by our company (R ¹ to R ⁸ are all in General Formula 1) 10 parts of a hydrogen atom and corresponding to a compound in which X is a 2,2-dimethyl-1,3-propylenebis-4,4′-phenylene group. 45 parts of 6,6-nylon, 0.6 parts of 1,3,5-triacroylhexahydro-s-triazine and 0.02 part of paramethoxyphenol were introduced from the second inlet, A polymer alloy composition was prepared in exactly the same manner. This composition was molded to prepare 20 test pieces identical to those in Example 1. Ten of them were subjected to a combustion test one week later. The test piece showed a flame drip. The remaining 10 pieces were irradiated with 40 kGy of γ rays, and a twist firing test was conducted one week later. No flame drip was seen. These test results are shown in Table-1. The surface condition after one week of each test piece was the same as in Example 1.

(Comparative Example 3)
Test piece in exactly the same manner as in Example 3 except that 0.6 part of 1,3,5-triacroylhexahydro-s-triazine and 0.02 part of paramethoxyphenol added in Example 3 were not added. 20 pieces were made. This was subjected to a combustion test in the same manner as in Example 3. A flame drip was observed regardless of whether or not the gamma rays were treated. The results are shown in Table-1.

Example 4
55 parts of the same polyphenylene ether resin, 0.3 part of maleic anhydride and 8 parts of PX-200 used in Example 1 were charged from the first inlet of the extruder used in Example 1. From the second inlet, 45 parts of 6,6-nylon and 2 parts of di (diallylamino) phenylphosphine oxide produced by our company were added. Thereafter, a polymer alloy composition was prepared in the same manner as in Example 1. This composition was molded to prepare 20 test pieces identical to those in Example 1. Ten of them were subjected to a combustion test one week later. There was no flame drip during the test. The remaining 10 pieces were irradiated with 40 kGy of γ rays and a combustion test was conducted one week later. There was no flame drip on the specimen. These test results are shown in Table-1. The surface condition after one week for each test piece was the same as in Example 1.

(Comparative Example 4)
A polymer alloy composition was prepared in the same manner as in Example 4 except that 8 parts of PX-200 charged in Example 4 was changed to 10 parts and 2 parts of di (diallylamino) phenylphosphine oxide was changed to 0 part. Thus, 20 test pieces were prepared. This test piece was subjected to a combustion test in the same manner as in Example 4. A flame drip was observed regardless of whether or not the γ rays were treated. The test results are shown in Table-1.

(Example 5)
A polymer alloy composition was prepared in exactly the same manner as in Example 1, except that 10 parts of the organophosphorus compound PX-200 charged in Example 1 was replaced with 10 parts of di (2,6xylenyl) phenyl phosphate. This composition was molded to prepare 20 test pieces identical to those in Example 1. This was subjected to a combustion test in the same manner as in Example 1. No drip was observed with or without gamma irradiation. These test results are shown in Table-1. The surface condition after one week for each test piece was the same as in Example 1.

(Comparative Example 5)
A polymer alloy composition was prepared in exactly the same manner as in Example 5 without adding 1 part of the triallyl isocyanurate charged in Example 5, and then 20 combustion test pieces were prepared in the same manner as in the combustion test. Was done. A flame drip was observed regardless of whether or not the gamma ray was irradiated. The test results are shown in Table-1.

表−１中、Ｖ−０はＵＬ−９４の試験方法で最も高い難燃性の格付けであり、何れもドリップを生じなかった。Ｖ−２は燃焼時間は比較的に短時間であったが火炎のドリップを生じたのですべてこの格付けにされた。

In Table 1, V-0 is the highest flame retardant rating in the UL-94 test method, and no drip occurred. V-2 was all given this rating because it had a relatively short burn time but produced a flame drip.

Claims (11)

  A method for flame-retarding polyamides, comprising adding an organophosphorus compound and a polyfunctional monomer to a polymer alloy of polyamides and polyphenylene ether resin.   A method for flame-retarding polyamides, characterized in that a polymer alloy of a polyamide and a polyphenylene ether resin irradiates a molded product having a composition containing an organophosphorus compound and a polyfunctional monomer.   The method for flame-retarding a polyamide according to claim 1 or 2, wherein the composition of the polymer alloy of the polyamide and the polyphenylene ether resin is 35 to 70% by weight of the polyamide and 65 to 30% by weight of the polyphenylene ether resin.   The method for flame-retarding polyamides according to any one of claims 1 to 3, wherein in the polymer alloy of polyamides and polyphenylene ether resin, the continuous phase is polyamides and the dispersed phase is polyphenylene ether resin.   The method for flame-retarding polyamides according to any one of claims 1 to 4, wherein the organic phosphorus compound is a phosphate ester.   The method for flame-retarding polyamides according to any one of claims 1 to 5, wherein the organic phosphorus compound is a phosphoric ester having two phosphorus atoms in one molecule. The method for flame-retarding polyamides according to any one of claims 1 to 6, wherein the organophosphorus compound is represented by the general formula 1.

(Wherein R ¹ to R ⁸ may be the same or different, and are a hydrogen atom or a methyl group, X is a paraphenylene group, a metaphenylene group, a 4,4′-biphenylene group, 3,3 ′, 5, , 5′-tetramethyl-4,4′-biphenylene group, 2,2-dimethyl-1,3-propylenebis-4,4′-phenylene group or 2,2-dimethyl-1,3-propylene group .)   The method for flame-retarding polyamides according to any one of claims 1 to 7, wherein the addition amount of the organophosphorus compound is 2 to 20% by weight based on the polymer alloy of the polyamides and the polyphenylene ether resin.   The polyfunctional monomer is at least one selected from 1,3,5-triacroyl hexadro-s-triazine, triallyl isocyanurate or di (diallylamino) phenylphosphine oxide. The method for making a polyamide flame retardant described in 1.   The method for flame-retarding polyamides according to any one of claims 1 to 9, wherein the polyfunctional monomer is added in an amount of 0.2 to 5% by weight based on the polymer alloy of the polyamides and the polyphenylene ether resin.   11. The γ-ray dose of 3 to 100 kGy applied to a molded article comprising a composition comprising a polyamide and a polyphenylene ether resin containing an organophosphorus compound and a polyfunctional monomer. Flame retardant method for polyamides.