JP2001247778A - Flame retardant resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flame retardant resin composition having the following properties, that is low metal corrosivity and excellent insulation resistance at normal temperature or a low temperature, or in a long use, containing no halogen, and is environment-friendly, safe and stable. SOLUTION: The flame retardant resin composition consists of (A) a thermoplastic resin, (B) a stabilized red phosphorus, (C) zinc borate and/or zinc stannate, and (D) an oxidant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a safe and stable non-halogen flame-retardant resin composition.

[0002]

2. Description of the Related Art Thermoplastic resins have excellent physical and chemical properties and are therefore used in large quantities in a wide range of fields such as electricity, machinery, automobiles and construction. In recent years, in the pursuit of high functionality of materials in the entire industry, demands for physical properties of thermoplastic resins have become even higher. Above all, the demand for safety is particularly high. In making the thermoplastic resin composition flame-retardant, not only the conventional flame-retardant method as in the past, but also the use of products from production work, and further incineration or landfill treatment In all situations, high levels of safety and stability are required.

Various methods have been proposed for flame retarding thermoplastic resins. In general, a method in which an organic halogen compound, an organic phosphorus compound, antimony trioxide or the like is blended into a thermoplastic resin composition alone or in combination is used. Of these methods, the method of using a brominated flame retardant as an organic halogen compound and combining it with antimony trioxide in a resin composition can be applied to any type of resin, from general-purpose plastics to engineering plastics,
Until now, it has been the mainstream of flame retardant technology.

[0004] However, a molded article of a resin composition containing an organic halogen compound is accompanied by a large amount of smoke during combustion and is accompanied by a large amount of toxic gas. In some cases, it has been gradually revealed that toxic gases contain highly toxic dioxins. From such a background, the application range of the flame retardant technology by blending an organic halogen compound is rapidly being restricted.

[0005] On the other hand, phosphorus compounds are flame retardants which have a relatively low risk of toxic gas generation. However, the flame retardant effect of an organic phosphorus compound, which is a typical phosphorus-based compound, is generally lower than that of an organic halide, and sufficient flame retardancy can be obtained by blending only an organic phosphorus compound as a flame retardant into a resin composition. In order to provide, a large amount of addition is required, and as a result,
Reduce the heat resistance and mechanical strength of the resin composition,
May increase water absorption, resulting in deformation and craze.

[0006] Among phosphorus-based compounds, red phosphorus can impart effective flame retardancy to a resin composition by adding a relatively small amount thereof, and lowers the inherent heat resistance and mechanical strength of the resin. Less is. Further, red phosphorus can be widely used as a flame retardant, from general-purpose plastics to engineering plastics.

[0007] However, red phosphorus itself is unstable against heat, friction, impact, and the like, and involves danger in storage and handling, particularly when kneaded with a resin. That is, red phosphorus reacts with moisture and oxygen in the air to generate a harmful gas of phosphine. Although red phosphorus is superior in environmental safety to halogen-based flame retardants, it is not perfect and its use has been quite limited in the past.

When blending red phosphorus into a resin, commercially available red phosphorus is rarely used as it is, and is usually used after performing a stabilizing treatment for forming a coating of another material on red phosphorus.

[0009]

However, it is difficult to form a complete coating on red phosphorus, and the generation of phosphine cannot be completely suppressed. For this reason, depending on the extrusion / molding processing temperature, shearing stress, secondary processing temperature and humidity of the resin composition, and the temperature and humidity of the product use environment,
Phosphine is generated from minute defects in the red phosphorus coating. Further, depending on the processing conditions and use conditions of the resin composition, the coating of red phosphorus may be peeled off, and phosphine is generated from the peeled portion, and the amount of the generated phosphine gradually increases. Furthermore, the thermal stability of the resin composition also decreases with time due to the loss and peeling of the coating of red phosphorus.

[0010] Then, the phosphine is oxidized in the air to generate phosphoric acid. Phosphoric acid has the property of corroding metals and carbonizing organic components, and may corrode metals in the vicinity of resin molded products in electric and electronic parts, or carbonize the molded products themselves. Also, the mold used for molding may be corroded.

The generation of phosphoric acid itself can be suppressed by adding an additive for suppressing the generation of phosphine to the resin composition. However, when a molded article of the resin composition is stored for a certain period or more, bleeding of a liquid material occurs on the surface of the molded article. This bleed is accompanied by a change in appearance such as wetting of the surface of the molded product, and gradually lowers the characteristics inherent to plastic such as mechanical characteristics and insulation resistance.

An object of the present invention is to provide a flame-retardant resin composition containing red phosphorus, which suppresses the generation of phosphine, suppresses bleeding of a liquid substance, and improves the mechanical properties and electrical properties of a molded article. An object of the present invention is to provide a non-halogen flame-retardant resin composition which has a small decrease in properties, has low metal corrosiveness even when used at a high temperature or for a long time, and has excellent insulation resistance.

[0013]

That is, the present invention provides:
(A) 100 parts by weight of a thermoplastic resin, (B) red phosphorus 0.5
To 30 parts by weight, (C) 2 to 80 parts by weight of zinc borate and / or zinc stannate, and (D) oxidizing agent 0.001 to 0.003.
It is a flame-retardant resin composition comprising 0 parts by weight. Hereinafter, the present invention will be described in detail.

[Thermoplastic resin (A)] Examples of the thermoplastic resin include thermoplastic polyester, polycarbonate, polyamide, polyimide, polyphenylene oxide, polyacetal, cellulose acetate (cellulose resin), polyvinyl chloride, polyethylene, polypropylene and polystyrene. , Styrene-acrylonitrile copolymer (AS resin), acrylonitrile-butadiene-styrene resin (ABS resin), methacrylic resin, fluororesin, and ionomer resin. For use in electric and electronic parts, it is preferable to use a thermoplastic polyester as the thermoplastic resin. Thermoplastic polyester is a polyester comprising a dicarboxylic acid component and a diol component, and examples of the dicarboxylic acid unit include terephthalic acid and naphthalenedicarboxylic acid.
Examples of the diol component include ethylene glycol and tetramethylene glycol. Suitable thermoplastic polyesters include polytetramethylene terephthalate, polyethylene terephthalate, polyethylene-
Examples thereof include 2,6-naphthalenedicarboxylate and polyester elastomers.

The thermoplastic resin used is not limited to one kind, but may be a mixture of two or more kinds.

[Red Phosphorus (B)] As red phosphorus, a particulate or powdered one is used. In order to improve the stability, it is preferable to provide a coating layer on red phosphorus and use it as stabilized red phosphorus. Usually, stabilization is achieved by providing one or more coating layers on the red phosphorus particles.
Both organic and inorganic substances can be used for the coating layer. As the organic substance, for example, a thermosetting resin can be used. Red phosphorus particles provided with a coating layer of a cured product of a thermosetting resin are a preferred embodiment as red phosphorus. As the inorganic substance, for example, a metal hydroxide such as aluminum hydroxide and zinc hydroxide can be used.

The particles of red phosphorus covered by the coating layer take a shape having a crushed surface or a sphere-like shape having no crushed surface as the shape of the particles. When the red phosphorus particles are produced through a pulverizing step, they take a particle shape with a crushed surface, and when they are produced without a pulverizing step, they take a spherical particle shape without a crushed surface. In the present invention, a sphere-like particle shape is preferable because the surface of the particles of red phosphorus is easily coated, a coating layer without defects is easily formed, and the formed coating layer is less likely to peel off. That is, the red phosphorus particles are preferably spherical red phosphorus particles having no crushed surface and directly obtained by a yellow phosphorus conversion treatment method that does not require pulverization.

When a particulate phosphorus is used as red phosphorus,
The average particle size of the red phosphorus particles is preferably from 1 to 150 μm. When using stabilized red phosphorus having a coating layer as red phosphorus, the average particle size of the stabilized red phosphorus particles including the coating layer is 200 μm. Hereinafter, the thickness is more preferably 5 to 150 μm. The use of stabilized red phosphorus having an average particle diameter in this range makes it possible to maintain good mechanical properties of the resin composition.

The content of red phosphorus is 0.5 to 30 parts by weight, preferably 0.5 to 2 parts by weight, per 100 parts by weight of the thermoplastic resin.
9 parts by weight. If the amount is less than 0.5 part by weight, the flame retarding effect is poor. If the amount exceeds 30 parts by weight, the mechanical properties are significantly reduced and the amount of phosphine generated is increased.

[Zinc borate, zinc stannate (C)] Zinc borate,
One of these zinc stannates may be used alone, or two or more thereof may be used. It can also be used as a mixture.

As the stannic acid of zinc stannate, both metastannic acid and hydroxystannic acid can be used. In both zinc borate and zinc stannate, water molecules may be hydrated. In the present invention, it is particularly preferable to use zinc borate and / or a hydrate thereof from the viewpoint of improving the flame retardancy and the electrical properties.

The amount of zinc borate and / or zinc stannate is from 2 to 80 parts by weight per 100 parts by weight of the thermoplastic resin.
Preferably it is 5 to 60 parts by weight. If the amount is less than 2 parts by weight, the flame retardancy and the electrical insulation cannot be expressed in a well-balanced manner. If it exceeds 80 parts by weight, the mechanical properties are poor.

[Oxidizing agent (D)] The oxidizing agent (D) used in the present invention is a substance capable of substantially oxidizing phosphine, for example, a metal composed of chromium, manganese, iron, copper, molybdenum, silver, or the like. Oxides; organic peroxides such as p-menthane hydroperoxide and t-butyl hydroperoxide; and compounds having an electron withdrawing group such as trans-cinnamic aldehyde. Among them, metal oxides having good thermal stability during processing are preferable, and metal oxides of one or more selected from the group consisting of chromium, manganese, iron, copper, molybdenum, and silver are more preferable.

The amount of the oxidizing agent (D) to be added is as follows.
The amount is 0.001 to 30 parts by weight, preferably 0.01 to 10 parts by weight, per 100 parts by weight. If the amount is less than 0.001 part by weight, the ability to oxidize phosphine is small, and the effect of suppressing phosphine is small. If the amount exceeds 30 parts by weight, the stability of the obtained resin composition will be impaired, and the mechanical properties will be poor. By blending the oxidizing agent in this range, a resin composition having substantially no metal corrosion and having excellent insulation resistance can be obtained.

[Porous Inorganic Compound / Layered Clay Mineral] To the resin composition of the present invention, a porous inorganic compound such as activated carbon and zeolite; and a layered clay mineral such as hydrotalcite, zirconium phosphate, montmorillonite and mica are added. You can do it. In this case, it is a preferable embodiment because more favorable low metal corrosion resistance, insulation resistance and flame retardancy can be obtained. That is, in the present invention, it is preferable to mix a porous inorganic compound and / or a layered clay mineral.
When the amount of the porous inorganic compound and / or the layered clay mineral is mixed, the amount is preferably 0.01 to 10 parts by weight per 100 parts by weight of the thermoplastic resin.

The porous inorganic compound and the layered clay mineral may be subjected to an organic modification treatment on one or both of the surface and the interior.
One or both of the inorganic modification treatments may be performed before use.

[Inorganic filler] The resin composition of the present invention may contain an inorganic filler. Calcium carbonate, titanium oxide, feldspar mineral, clay, organized clay, white carbon, carbon black, glass beads Granular or amorphous fillers such as, for example; plate-like fillers such as kaolin clay and talc; flaky fillers such as for glass flakes, mica, graphite, etc .; glass fibers, carbon fibers, wollastonite, A fibrous filler such as potassium titanate can be blended. Above all, glass fibers are preferred in order to obtain better performance in mechanical strength and heat resistance.

When the inorganic filler is compounded, the compounding amount is preferably 200 parts by weight or less, more preferably 5 to 150 parts by weight, particularly preferably 10 to 100 parts by weight, per 100 parts by weight of the thermoplastic resin.

[Other additives] The resin composition of the present invention contains a nucleating agent, a lubricant, an antioxidant, an ultraviolet absorber, a heat stabilizer, an antistatic agent, a pigment within a range not to impair the object of the present invention. May be added.

A flame retardant other than red phosphorus may be added. Examples of the flame retardant include inorganic compounds such as aluminum hydroxide and magnesium hydroxide; phosphates, phosphates, phosphinates, and phosphinates. Mono-compounds composed of isophosphorous compounds or condensates or polymers thereof; siloxane oligomers or polymers composed of alkyl siloxanes and aryl siloxanes can be used.

A flame retardant auxiliary may be added. Examples of the flame retardant auxiliary include nitrogen compounds such as melamine cyanurate and tetrazole, novolak type phenol resins, phenol / formaldehyde resins, and expandable graphite. Can be.

Further, in order to further enhance the effect of the flame retardant, a compound which suppresses dripping of molten particles during combustion may be added. As such a compound, for example, polytetrafluoroethylene or fumed colloidal silica produced by emulsion polymerization can be used.

For the purpose of improving heat resistance, an antioxidant such as a hindered phenol compound, an aromatic amine compound, an organic phosphorus compound, a sulfur compound, or a heat stabilizer may be added.

[Production Method] The resin composition of the present invention can be produced by a known method, and the resin composition can be formed into a molded article by a known method.

For example, 1) a method of mixing the components, kneading and extruding with an extruder to prepare pellets, and subjecting them to molding to form molded articles; 2) once preparing pellets having different compositions, Are mixed in a predetermined amount and subjected to molding to obtain a molded article composed of a resin composition having a target composition. 3) A method in which one or more of each component is directly charged and molded into a molding machine to form a molded article. Can be used.

A portion of the resin component may be added as a fine powder mixed with other components. This method is a preferable method for uniformly mixing the components.

[0037]

The present invention will be described below in detail with reference to examples. The various characteristics in the examples were measured by the following methods.

A. Generated amount of phosphine Dry at 130 ° C for 5 hours to form dry pellets, pack 3g of the dried pellets into a 22ml vial, hold in a headspace sampler at 120 ° C for 1 hour, measure the phosphine generated during this time by GC Then, the amount of phosphine was detected by NPD.

B. Bleeding property of liquid material A pellet test piece (20 mm × 20 mm ×
1 mm ^t ) was prepared and left in a constant temperature / humidity bath at 40 ° C. and 85% RH for 72 hours. Thereafter, the liquid substance adhering to the flat plate surface was eluted in pure water, and the obtained aqueous solution was analyzed by ion chromatography to measure the amounts of phosphate ions and phosphite ions.

C. Insulation resistance evaluation The test specimen was left in a thermo-hygrostat at 45 ° C. and 95% RH for 100 hours, and then conditioned in a test chamber at 23 ° C. and 50% RH for 48 hours to measure the volume resistivity of the test specimen. did.

D. Evaluation of metal corrosiveness Dried pellets were dried at 130 ° C. for 5 hours. 3 g of the dried pellets were packed in a 22-ml vial, and a rectangular silver plate was put therein and sealed. 120 ° C sealed vial
And the state of corrosion was visually determined.

E. Evaluation of Flame Retardancy Flame retardancy was evaluated using a 0.8 mm thick test specimen according to the UL94 Standard Vertical Burning Test Method. Flame retardancy was evaluated as V-0, V-1, V-2, HB according to the evaluation method described in UL94.
Classified.

Examples 1-2, Comparative Examples 1-4, and Reference Examples 1-3 Polytetramethylene terephthalate having an intrinsic viscosity of 0.75 dl / g and a terminal carboxyl group concentration of 20 eq / T (10 ⁶ g) (Table 1) Abbreviated as “PBT”), glass fiber, red phosphorus, phenolic resin, zinc borate, zinc oxide covered with an organic layer and an inorganic layer and stabilized.
Copper oxide (I) and copper oxide (II) were blended in the composition shown in Table 1, and kneaded at 250 ° C. using a 44 mmφ twin-screw extruder with a vent, extruded into strands and pelletized.

[0044]

[Table 1]

The above evaluation was performed using the pellets. Table 2 shows the results.

[0046]

[Table 2]

[0047]

According to the present invention, even when used at a high temperature or for a long time, metal corrosion is low, insulation resistance is excellent, and harmful gases and bleed are suppressed by halogen-free, safe and stable. It is possible to provide an excellent flame-retardant resin composition.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 7/18 C08K 7/18 9/04 9/04 C08L 67/02 C08L 67/02 (72) Inventor Mikoko Suzuki 1-4-13 Onodai, Midori-ku, Chiba-shi, Chiba F-term in the Chiba Research Center, Teijin Limited (Reference) 4J002 AA011 BB031 BB121 BB231 BC031 BC061 BD041 BD121 BG051 BN151 CB001 CF061 CF071 CF081 CG001 CH561 CB001 DA001 FD136 FD137 FD138 FD209 GQ00

Claims (5)

[Claims] (A) 100 parts by weight of a thermoplastic resin,
Flame retardant resin composition comprising (B) 0.5 to 30 parts by weight of red phosphorus, (C) 2 to 80 parts by weight of zinc borate and / or zinc stannate, and (D) 0.001 to 30 parts by weight of oxidizing agent. . 2. The flame-retardant resin composition according to claim 1, wherein the red phosphorus (B) is stabilized red phosphorus. 3. The flame-retardant resin composition according to claim 1, wherein the thermoplastic resin (A) is a thermoplastic polyester. 4. The flame-retardant resin composition according to claim 2, wherein the stabilized red phosphorus is a red phosphorus particle having a coating layer of a cured product of a curable resin. 5. The flame-retardant resin composition according to claim 4, wherein the red phosphorus particles are sphere-like red phosphorus particles having no crushed surface and obtained directly by a yellow phosphorus conversion treatment method that does not require grinding.