JP3341974B2 - Flame retardant polyamide resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant polyamide resin composition comprising a crystalline partially aromatic polyamide resin containing a red phosphorus-based flame retardant and a fibrous or particulate reinforcing agent. It has excellent properties and chemical resistance and can obtain molded products with little change in dimensions and physical properties due to water absorption, and can be used in a wide range of fields such as electric field, electronic field, mechanical field, automobile field and building field. .

[0002]

2. Description of the Related Art Conventionally, polyamide resins have been widely used in electrical, mechanical, automotive, and architectural applications because of their excellent physical and chemical properties. At present, the demand for polyamide resins is becoming more severe. Especially electricity /
There is a strong demand for heat resistance and flame retardancy in electronic parts and automobile parts, and the UL standard is widely adopted for this flame retardancy, and it is essential that it be equivalent to V-0. For example, the use of aromatic polyamide and 4,6 nylon, which are heat-resistant high-melting polyamides, has been studied, and a resin composition in which a brominated polystyrene and an antimony compound are blended with the polyamide in order to impart flame retardancy has been proposed. Are known. However, since the flame-retardant composition has a high temperature at the time of melt molding, the flame retardant is liable to be decomposed or deteriorated, which tends to cause deterioration of moldability and poor appearance of a molded article.

[0003] Therefore, red phosphorus as a flame retardant and divalent range of 4
A method of adding an inorganic or organic compound of a valent metal is known from EP-A-92776. However, when a polyamide having a high melting point (275 ° C. or higher) is made flame-retardant by such a method, the stability of red phosphorus is insufficient, which leads to undesired components forming reaction and decomposition reaction. It has the disadvantage that it eventually affects the mechanical properties of the final product. It is also known from EP 141763 to use a combination of red phosphorus and a lanthanide compound as a flame retardant. This lanthanide compound considerably increases the product cost irrespective of the use of a trace amount, and in the case of a high melting point polyamide, there is still a problem in stability. In addition, JP-A-2-127466 and JP-A-3-197553
The publication also uses red phosphorus as a flame retardant, and uses an inorganic compound of a divalent or tetravalent metal, an organic mono- or dicarboxylic acid, an organic carboxylic acid having 6 to 24 carbon atoms, It is known to treat with an ester of an alcohol having from 24 to 24 carbon atoms or a metal salt of the above-mentioned acid or a mixture thereof, or to treat with a polyurethane or polyester-polyurethane for stabilizing red phosphorus, These methods are insufficient for stabilizing red phosphorus.

[0004]

Accordingly, the present invention provides a flame retardant for a polyamide having a high melting point, which does not cause a problem in the stability of the polyamide due to the compounded flame retardant. It is an object to provide uniform properties.

[0005]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have made intensive studies and studies and have finally completed the present invention. That is, the present invention relates to (A) 30 to 95% by weight of units derived from terephthalic acid and hexamethylenediamine.
25 to 65% by weight of a crystalline partially aromatic copolymerized polyamide resin having a melting point of 275 ° C. or higher, (B) 15 to 70% by weight of a fibrous reinforcing agent and / or a particulate reinforcing agent, (C)
A flame retardant characterized by containing 0.5 to 25% by weight of red phosphorus which generates 1.0 mg / g or less of phosphine after heating at 300 ° C. for 3 hours in air and 0 to 30% by weight of an elastomer (D). It is a conductive resin composition.

In the present invention, the crystalline partially aromatic copolymerized polyamide resin having a melting point of 275 ° C. or more is defined as a unit (T) of terephthalic acid (T) and hexamethylenediamine (6).
6) 40 to 95% by weight as an essential component, and as another copolymerization component, a saturated aliphatic dicarboxylic acid having 4 to 12 carbon atoms, an aromatic dicarboxylic acid, a saturated aliphatic diamine having 4 to 14 carbon atoms,
A polyamide obtained from aromatic diamines, lactams and the like. Specifically, as the acid component, adipic acid (6), azelaic acid (9), dodecanedioic acid (1)
2), isophthalic acid (I), terephthalic acid (T), naphthalenedicarboxylic acid (N), and the like. Examples of the amine component include diaminobutane (4), hexamethylenediamine (6), nonanediamine (9), Methylenediamine (10), methylpentamethylenediamine (MP
D), meta-xylylenediamine (MXD), para-xylylenediamine (PXD) and the like, and lactams include
ε-caprolactam, ω-aminoundecanoic acid, laurolactam and the like. Specific examples of the polyamide resin used in the present invention include nylon 6T / 6, nylon 6T / 66, nylon 6T / 6I, and nylon 6T / 66.
/ 6I, nylon 6T / 9T / 66, nylon 6T / M
And copolymerized polyamides such as PD-T / 66. Further, a blend of the above-mentioned copolymer and polymer may be used, but the present invention is not limited thereto. In the present invention, the unit derived from terephthalic acid and hexamethylenediamine contained in the copolymerized polyamide is 30 to 95.
% By weight, preferably 40 to 85% by weight, especially 50 to 80% by weight.
If it is less than 30% by weight, the melting point is low and the heat resistance is inferior. If it exceeds 95% by weight, the melting point is too high, causing some decomposition during processing, which is not preferable.

[0007] The flame-retardant polyamide resin composition according to the present invention must contain 15 to 70% by weight of a fibrous or / and particulate reinforcing agent, and preferably 25 to 60% by weight. If the amount of the reinforcing agent is less than 15% by weight, the reinforcing reinforcement of the reinforcing agent is low, and mechanical strength such as strength, rigidity heat deformation temperature, etc.
Little effect of improving thermal properties. Also, flame retardation by adding red phosphorus becomes difficult. Conversely, if the amount of the reinforcing agent exceeds 70% by weight, it becomes difficult to produce a flame-retardant polyamide resin, and when the resin is molded, the fluidity is significantly reduced and the moldability is poor.
Further, the appearance of the finished product is unfavorably deteriorated. Specific examples of the fibrous reinforcing agent used in the present invention include glass fiber, carbon fiber, aramid fiber, potassium titanate whisker, aluminum borate whisker, and fibrous silicate such as wollastonite acid. Further, specifically, glass beads as a particulate reinforcing agent,
Examples include silica, talc, mica, calcium carbonate, wollastonite, kaolin, clay, magnesium oxide, and alumina oxide. These reinforcing agents may use a silane coupling agent such as an aminosilane coupling agent, an epoxy silane coupling agent, or a titanate-based silane coupling agent for improving the adhesiveness with the polyamide resin, that is, for improving the strength and the Izod impact strength. .

The flame-retardant polyamide resin composition according to the present invention contains stabilized red phosphorus (having a phosphine generation amount of 1.0 mg / g or less after heating at 300 ° C. for 3 hours in air) of 0.5 to 2%.
It is necessary to mix 5% by weight. The flame retardancy of a resin by adding a halogen-based flame retardant increases proportionally as the amount of the halogen-based flame retardant is increased. Yes, if it is added in excess of the optimal amount, the flame retardancy will be worse, ie, it will burn well. In addition, in the case of flame retardation by using red phosphorus, the larger the amount of reinforcing agent added, the smaller the amount of red phosphorus added, and the reinforcing agent content and the optimum amount of red phosphorus are inversely proportional. When flame retardation is achieved by using red phosphorus, flame retardation can be achieved with about 1/2 to 1/3 of the halogen-based flame retardant. That is, red phosphorus has a remarkably superior flame retardant effect as compared with a halogen-based flame retardant, and furthermore, it is possible to make the resin flame-retardant by adding a small amount thereof. In addition, a large amount of black soot is generated when a halogen-based flame retardant is used during combustion. However, in the case of red phosphorus, black soot is hardly generated due to the use of a flame retardant.

The red phosphorus used in the present invention has a phosphine generation amount of 1.0 m after heating in air at 300 ° C. for 3 hours.
g / g or less, preferably 0.7 mg / g or less, particularly 0.1 mg / g or less.
Any red phosphorus may be used as long as it is 4 mg / g or less. In particular, sphere-like red phosphorus having no pulverized surface directly obtained by a yellow phosphorus conversion treatment method which does not require pulverization described in JP-A-63-110254. Or a thermosetting resin and / or
A red phosphorus flame retardant coated with aluminum hydroxide, magnesium hydroxide or zinc hydroxide is preferred. The compounding amount is 0.5 to 25% by weight, preferably 1.0 to 15% by weight, particularly preferably 2.0 to 10% by weight. If the amount is less than 0.5%, the flame-retardant effect is not sufficient, and if it exceeds 25% by weight, it burns well, and the mechanical properties are undesirably deteriorated.

The thermosetting resin for coating the red phosphorus includes phenol / formalin, urea / formalin, melamine / formalin, and furfuryl alcohol.
It is selected from a formalin type, an aniline / formalin type, a polyhydric alcohol / polybasic acid type and the like. Of the above resin groups, furfuryl alcohol / formalin, aniline /
In the case of formalin and polyhydric alcohol and polybasic acid, etc., the polymerization reaction is difficult to proceed in the presence of a large amount of water. It is desirable to add The conditions of the resin coating treatment vary somewhat depending on the type of thermosetting resin to be used. The condensate is added in an amount of 1 to 35 parts by weight with respect to 100 parts by weight of red phosphorus, and when using a raw material for resin synthesis, it is used at 40 to 100 ° C. for 1 to 3 hours.
Stir at 0 ° C. for 1-2 hours. At this time, if necessary, a polymerization catalyst and a filler such as aluminum hydroxide, magnesium hydroxide or titanium hydroxide can be coexisted. The addition of the filler increases the mechanical strength of the resin coating and has a hiding effect on the purple-red color peculiar to red phosphorus, which can contribute to the expansion of uses of the red phosphorus-based flame retardant. The amount of the filler is preferably 1 to 35 parts by weight per 100 parts by weight of red phosphorus. Separate and wash the product with water, 130-140 ° C
To complete the polymerization reaction, a red phosphorus-based flame retardant with extremely good stability can be obtained. In addition, if aluminum hydroxide or zinc hydroxide is previously adsorbed to the red phosphorus particles before coating with the thermosetting resin, the stability of the red phosphorus is further improved, and the flame retardant resin is used by using the red phosphorus. In the composition, the effect of the addition of the red phosphorus-based flame retardant hardly appears over a long period of time. The amount of the aluminum salt, magnesium salt or zinc salt to be added is preferably an amount necessary to produce 0.1 to 30 parts by weight of hydroxide based on 100 parts by weight of red phosphorus.

The flame-retardant polyamide resin composition according to the invention preferably contains up to 30% by weight, in particular 3 to 20% by weight, of an elastomer (also called impact-resistant polymer or rubber elastic). The elastomer may contain an olefin polymer containing an unsaturated dicarboxylic acid or an anhydride thereof and / or a styrene polymer. As the olefin polymer, various ones may be mentioned, and ethylene and C3 or more, preferably 3 to 6 are used.
Α-olefin copolymer (ethylene-propylene copolymer, ethylene-propylene-gen terpolymer,
Ethylene-butene-1 copolymer, etc.), copolymer of ethylene and vinyl compound (ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene-methacrylic acid) Copolymer, ethylene-methacrylic acid ester copolymer, ethylene- (meth) acrylic acid (ester) -α, β unsaturated carboxylic acid (derivative) terpolymer, ethylene-vinyl chloride copolymer, etc.) And those showing properties as an elastomer are particularly preferable. These are used alone or as a mixture.

The styrenic polymer also preferably exhibits an elastomeric property. Specifically, a known S (aromatic hydrocarbon polymer) -B (conjugated diene polymer) -S type And a so-called styrene block copolymer having a symmetric block type structure. S and B each represent a polymer block, and examples of the central block B include polybutadiene and polyisoprene, with butadiene being particularly preferred. It is also recommended that polybutadiene be partially saturated with an alkyl group (ethylene chain) (SEBS) by hydrogenation.
The both terminal blocks S represent a polymer block of an aromatic hydrocarbon, and a polymer block composed of polystyrene is preferable. The weight ratio of the aromatic hydrocarbon polymer to the conjugated diene polymer is preferably in the range of 10/90 to 90/10.
The range of 5/85 to 85/15 is more preferable.

The olefin polymer and / or the styrene polymer is preferably modified with an unsaturated dicarboxylic acid or an anhydride thereof. Specific examples of the unsaturated dicarboxylic acid or an anhydride thereof include maleic acid. , Itaconic acid, chloromaleic acid, citraconic acid, butenylsuccinic acid, tetrahydrophthalic acid, and the like, and anhydrides thereof. Of these, maleic anhydride is preferred. Also, as the denaturation method,
One or more of the above unsaturated dicarboxylic acids or acid anhydrides thereof are mixed with an olefin-based polymer and / or a styrene-based polymer in the presence of a peroxide. Knead at 250 ° C for 1 to 10 minutes and react. The amount of the unsaturated dicarboxylic acid or anhydride is preferably 0.1 to 5 parts by weight based on 100 parts by weight of the olefin-based polymer and / or the styrene-based polymer. The amount of the peroxide is 0.1 to 100 parts by weight of the olefin-based polymer and / or the styrene-based polymer.
It is preferably from 0.5 to 1 part by weight.

Further, the flame retardant polyamide resin composition used in the present invention may contain a conventional additive such as a lubricant, a releasing agent, a heat stabilizer, a weathering agent, a slidability improving agent, etc. A flame retardant aid for phosphorus, a stabilizer and the like may be added. Lubricants and release agents include carboxylic acid metal salts such as calcium stearate, barium stearate, magnesium stearate, calcium montanate, sodium montanate, and high molecular substances of montanic acid. , Methylenebisstearylamide, and waxes such as polyethylene wax and polyethylene oxide. Examples of the crystal nucleating agent include talc, silica, wollastonite, clay, and graphite. Examples of the heat stabilizer include a combination of a copper halide and a metal halide of Group 1 of the periodic table, for example, potassium iodide, hindered phenols,
Hindered amines and combinations thereof with sodium hypophosphite, organic phosphorus and the like can be mentioned. Examples of weathering agents include carbon black, benzophenone, triazole, imidazole, oxazole, hindered amine (HA)
LS) and the like. Examples of the slidability improver include high molecular weight polyethylene, acid-modified high molecular weight polyethylene fluororesin powder, molybdenum disulfide silicon resin, oil zinc, and the like. These are in a range that does not impair the resin properties, for example, about 0.05 to 3 weight. % May be added. In addition, as a flame retardant aid and stabilizer for red phosphorus, a metal hydroxide hydrotalcite such as magnesium hydroxide or the like may be added in an amount of about 0.5 to 10% by weight, but is not limited thereto. Absent.

The resin composition of the present invention is produced by kneading the above components using a single-screw extruder, a twin-screw extruder, a kneader, a twin-screw roll or the like. There is no particular limitation on the type of kneader used and the kneading conditions.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The composition of the present invention obtained by the above method can be molded into various molded articles, and the molding method is a commonly used method such as an injection molding method and an extrusion molding method. And a blow molding method. Specifically, as molded products, in the electric and electronic fields, coil bobbins, motors, transformers, sealing materials,
In the automotive field, such as cases, connectors, switches, SMT compatible parts, boards, sockets, plug switches, terminal boards, printer parts, etc., in the automotive field, cooling water system parts, engine parts, lamp sockets, coil bobbins, sealing material cases,
Examples include fuel injection pump parts, and other applications that are difficult for existing nylon resins due to high-temperature mechanical properties, dimensional changes due to chemical-resistant water absorption, changes in physical properties, and the like. However, it is not limited to these uses.

[0017]

The present invention will be specifically described below with reference to examples. The evaluation of physical properties in the present invention was measured by the following methods. Relative viscosity: Measured according to JIS K6810 (sulfuric acid solution). Melting point: The temperature at which the maximum value of the melting curve obtained by measuring 8 to 10 mg of a sample at a heating rate of 20 ° C./min using DSC (PERKIN-ELMER7 type) is defined as (Tm
-1). Samples 8 to 10 mg at a heating rate of 20 ° C
/ Min at (Tm-1) + 20 ° C. for 5 minutes, then cool to 30 ° C. at a temperature lowering rate of 20 ° C./min, hold for 5 minutes, and again at a temperature increasing rate of 20 ° C./min. Heat to (T-m-1) + 20 ° C. The temperature showing the maximum value of the melting curve at this time was defined as (Tm).

[0018] Flame retardancy: conforms to UL Standard Subject94. Conducted with a molded product thickness of 1/32 '. Productivity: Extrusion processing ○ mark: Continuous production possible × mark: Strands discharged from the nozzle are cut off frequently and cannot be produced. Molded product appearance: ○: glossy and the surface is smooth △: gloss is reduced but the surface is almost smooth × mark: no gloss and the whole surface is rough Flexural strength: Flexural modulus: according to ASTM D-790

Generated amount of phosphine: The red phosphorus flame retardant is heated at a predetermined temperature of 300 ° C. for 3 hours under a nitrogen stream to collect generated nitrogen gas containing phosphine. The volume of the collected gas and the phosphine concentration in the gas are measured. The amount of phosphine is calculated from the gas volume and the phosphine concentration, and the phosphine amount is calculated by converting the amount per gram of red phosphorus. The phosphine concentration was measured by the "Kitakawa gas detection tube method". Thermal deformation temperature (18.6 kg / cm ² load): ASTM
According to D-648. Dielectric breakdown strength: according to ASTM D-149. (Molded product thickness = 1 mmt) Retention after PCT treatment: Predetermined test piece at 121 ° C
The test piece is immersed in hot water of × 2 atm for 200 hours, and then the test piece is vacuum dried for 2 days at 80 ° C. to remove the absorbed water. The bending strength and the dielectric breakdown strength after the PCT treatment are measured and compared with the characteristic values before the PCT treatment to determine the retention. Retention (%) = (characteristic value after PCT processing / characteristic value before PCT processing) × 100

Examples 1 to 7, Comparative Examples 1 to 6 Same-direction 35φ twin-screw extruder (TEX35 manufactured by Toshiba Corporation)
The cylinder temperature was set at a temperature about 10 to 15 ° C. higher than the melting point of each component A (crystalline partially aromatic copolymerized polyamide resin) shown in Table 1. The screw rotation speed was fixed at 100 rpm, A component (polyamide resin), release agent (calcium montanate 0.4 pH) from the hopper side.
R), a heat stabilizer (Hindered amine-based Nowgard 44)
5 0.4pHR, Irgafos 1 which is a phosphorus stabilizer
68 0.3 pHR), various red phosphorus-based flame retardants as component C shown in Table 2, and a particulate reinforcing agent as component B were weighed in predetermined amounts, and then uniformly blended with a tumbler and then charged. Further, nitrogen gas was blown (4 liter / min) to prevent ignition of red phosphorus by the frictional heat of the extruder screw. The glass fiber of the component B was charged from the side feed portion and kneaded. The strand discharged from the extruder nozzle was water-cooled and then cut (2.5φ × 2.5) with a cutter to obtain pellets for testing. After water cooling, the cut resin pellets were immediately dried with hot air at 130 ° C. for 3 hours to reduce the pellet moisture content to 0.1% or less. Various resin pellets (flame-retardant polyamide resin) were molded into target test pieces using a Toshiba IS-100 injection molding machine. Molding conditions: Cylinder temperature: 10 to 1 from melting point of component A
Set at 5 ° C higher temperature. Mold temperature: 135 to 140 ° C. Tables 3 to 5 show the physical properties of the obtained compositions.

[0021]

[Table 1]

[0022]

[Table 2] In Table 2, Nova Excel is red phosphorus manufactured by Rin Kagaku Kogyo Co., Ltd.

[0023]

[Table 3] As is clear from Table 3, the amount of reinforcing agent (glass fiber) was 1
If it is less than 5% by weight (Comparative Examples 1 and 2), it can be seen that the effect of improving the mechanical and thermal properties is small, and that the flame retardant effect due to the addition of red phosphorus is insufficient. On the other hand, when the amount of the reinforcing agent is in the range of 15 to 70% by weight, particularly 25 to 60% by weight (Examples 1 and 2), the mechanical and thermal properties are excellent and the flame retardancy is also excellent. When the amount of the reinforcing agent exceeds 70% by weight (Comparative Example 3),
Although the flame retardancy is excellent, the productivity, the appearance of the molded product, and the mechanical properties (flexural strength) are deteriorated, which is not preferable.

[0024]

[Table 4] Examples 3 and 4, which are the compositions of the present invention, were prepared in air at 300 ° C. ×
This is the case where stabilized red phosphorus, which generates phosphine in an amount of 1.0 mg / g or less after heating for 3 hours, is used. As is clear from Table 4, the flame retardancy is good, and the PCT treatment (121 ° C.)
It can be seen that the mechanical and electrical properties after hot water treatment at 2 atm for 300 hours) were also excellent. Comparative Examples 4, 5, and 6 are cases in which unstable red phosphorus having a phosphine generation amount of 1.0 mg / g or more was used, and the mechanical and electrical properties were significantly reduced by the PCT treatment. You can see that.

[0025]

[Table 5] In Tables 3 to 5, B-1 and B-2 are as shown below. B-1: Glass fiber (Nippon Sheet Glass Co., Ltd., brand name: RES)
O3-TP57) B-2: Talc (Hayashi Chemical Co., Ltd., brand: Micron White # 5000A)

[0026]

The effects of the composition of the present invention are evident from Tables 3 to 5 above. Not only excellent heat resistance and flame retardancy, but also its excellent mechanical and electrical properties,
It can be used in various fields such as electronics and automobiles, especially in areas where existing polyamide resins are difficult due to high temperature, mechanical properties, chemical resistance, changes in dimensions and physical properties due to water absorption, etc. It is great to contribute.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ identification code FI C08K 3:34) C08L 21:00 (C08L 77/06 21:00) (58) Fields surveyed (Int.Cl. ⁷ , DB Name) C08L 77/06 C08K 7 / 14,3 / 32 C08K 3 / 34,13 / 04

Claims (1)

(57) [Claims] (A) 25 to 65% by weight of a crystalline partially aromatic copolymerized polyamide resin containing 30 to 95% by weight of units derived from terephthalic acid and hexamethylenediamine and having a melting point of 275 ° C. or more; ) Fibrous reinforcing agents and / or particulate reinforcing agents
(C) 0.5 to 25% by weight of red phosphorus having a phosphine generation amount of 1.0 mg / g or less after heating in air at 300 ° C. for 3 hours.
And (D) a flame retardant resin composition containing 0 to 30% by weight of an elastomer.