JPH0726005B2 - Flame-retardant polyester resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a flame-retardant polyester resin composition, and more particularly to a flame-retardant polyester resin composition having improved fluidity during molding.

[Prior Art] Thermoplastic polyester resins, particularly polyalkylene terephthalate resins typified by polyethylene terephthalate and polybutylene terephthalate, have high heat resistance,
It has excellent physical properties such as mechanical properties, electrical properties, and chemical resistance, and is widely used in industrial products.

However, the above-mentioned polyester resin has the property that it is not sufficiently flame-retardant and is relatively flammable.

Various methods have been proposed for the purpose of imparting flame retardancy to this polyester resin. For example, various organic halogen compounds,
Attempts have been made to add an organic phosphorus compound, an organic nitrogen compound, etc., in combination with a flame retardant auxiliary agent, or to react a halogen compound with a polymer skeleton. Is used to make the polyester resin flame-retardant. By these methods, a practically useful polyester resin composition can be obtained in many cases.

However, in recent years, molded products have become thinner and smaller, and along with this, there has been a strong demand for improving the fluidity of the resin composition melted during molding. Further, in order to shorten the molding cycle and improve the productivity of molded products, a resin composition having improved fluidity during molding is desired.

As a method for improving the fluidity of the resin composition at the time of melting, a means for lowering the degree of polymerization of the polymer used in the resin composition is used, and this improving means is a decrease in the mechanical strength characteristics of the molded product. In many cases, it is not a preferable improvement means. Further, means for adding and blending various plasticizers is also known, but in this case as well, there is a problem such as exudation of the plasticizer on the surface of the molded product in addition to deterioration of mechanical strength characteristics, and it can be said that it is a preferable improving means. Absent.

[Object of the Invention] The present invention has been made in view of such circumstances, and an object thereof is to reduce mechanical strength characteristics and the like in a flame-retardant polyester resin composition containing brominated polystyrene. It is intended to provide a resin composition having improved fluidity when melted without causing any trouble.

[Structure of the Invention] The flame-retardant polyester resin composition of the present invention for achieving the above object is shown as follows. That is, brominated dioctyl phthalate 3-40 wt% and brominated polystyrene 97-
A flame-retardant polyester resin composition containing 60% by weight of a flame retardant.

The polyester in the present invention means a polymer obtainable by polycondensation of an aromatic dicarboxylic acid and / or an aromatic oxycarboxylic acid and a diol. Typical of such polyesters are polyethylene terephthalate, polybutylene terephthalate, hexamethylene terephthalate, polyethylene naphthalene dicarboxylate, polybutylene naphthalene dicarboxylate, polyhexamethylene naphthalene dicarboxylate, polyhexamethylene-4,4'-diphenyl. Homopolymers or copolymers such as dicarboxylate are exemplified. From the industrial viewpoint, polyethylene terephthalate, polybutylene terephthalate and polymer blends of both are particularly preferable.

The brominated polystyrene referred to in the present invention is represented by the following general formula (I) Produced by polymerizing brominated styrene or brominating polystyrene. Brominated polystyrene having a weight average molecular weight of 100,000 to 1,000,000 is preferably used here. Of course, brominated polystyrene having a relatively low weight average molecular weight of, for example, about 5,000 can be used.

Further, the compound of the general formula (I) can be used even if another vinyl compound is copolymerized. Examples of the vinyl compound in this case include styrene and α-methylstyrene.

The brominated dioctyl phthalate used in the composition of the present invention is represented by the following general formula (II), [However, p is an integer of 1-4] It is manufactured by brominating commercially available dioctyl phthalate. The brominated polystyrene and the brominated dioctyl phthalate may be separately produced and then mixed in the range of the composition of the present invention, or the polystyrene and the dioctyl phthalate may be mixed and then both are brominated at the same time. In the blending ratio, the weight ratio of brominated dioctyl phthalate / brominated polystyrene is 3-40 / 97-6.
0, preferably 4 to 25/96 to 75, more preferably 5 to 20/9
5 to 80. If the amount of brominated dioctyl phthalate is less than the above range, the fluidity of the resin composition melted during molding will not be improved. On the other hand, if the proportion is more than the above range, the fluidity at the time of molding is improved, but the mechanical strength characteristics of the molded product tend to deteriorate, which is not preferable.

The ratio of the total amount of brominated dioctyl phthalate and brominated polystyrene to the entire resin composition depends on the degree of flame retardancy required, and is 1 to 30% by weight, and further 2 to 20%.
It is preferably in the range of% by weight. If it is less than 1% by weight, the flame retardance may be insufficient, and if it exceeds 30% by weight, the resulting resin composition tends to be markedly deteriorated in properties.

The flame-retardant resin composition of the present invention can easily make the composition flame-retardant by using an inorganic flame-retardant auxiliary together. As an example, antimony trioxide, antimony pentoxide,
Examples thereof include antimony compounds such as sodium antimonate, barium metaborate, boron compounds such as zinc borate, zirconium compounds, molybdenum compounds, and the like. Of these, antimony compounds are preferably used. A flame-retardant aid whose surface is coated with a thermosetting resin or a silicone resin may be used. When this inorganic flame retardant aid is used in combination, the amount added is preferably 0.5 to 20% by weight, more preferably 1 to 10% by weight, based on the total composition. If it is less than 0.5% by weight, the flame-retardant effect is not sufficient, and if it exceeds 20% by weight, the properties of the composition such as mechanical strength as a molded article are remarkably deteriorated, so that the composition is not preferable.

Various additives may be added to the resin composition of the present invention in order to impart necessary functions depending on the use and purpose. Examples of the inorganic additive include glass fiber, carbon fiber, potassium titanate fiber, wollastonite, asbestos, sepiolite, glass beads, glass flakes, talc, mica, feldspar, calcium carbonate, silica and the like. The amount added is preferably 0 to 60% by weight based on the total composition. If it exceeds 60% by weight, not only the molding processability of the composition is lowered, but also the mechanical strength characteristics are remarkably lowered, which is not preferable.

In addition, if necessary, a heat stabilizer (such as a phosphorus compound), an antioxidant (such as a phenol compound), a crystal nucleating agent (such as a metal salt of an organic acid), a release agent, a colorant, an ultraviolet absorber. It does not matter if an antistatic agent or the like is added.

The combined use of a diepoxy compound, which is generally added to improve the strength of polyester, is also effective for improving properties such as mechanical strength. Furthermore, the addition of other types of polymers, especially polycarbonates, polyolefins, acrylic elastomers, etc., is effective in improving the impact strength of the resin composition of the present invention.

Although any physical means can be adopted for producing the composition of the present invention, a general and desirable method is to blend polyester and each additive in a predetermined amount, and then melt-knead in an extruder to obtain a uniform mixture. The method of pelletizing after making into pellets is mentioned.

Thus, the fluidity during molding is improved, and a composition having a high degree of flame retardancy and excellent mechanical strength properties can be obtained.

The composition of the present invention is used as a molding material,
It can be suitably used for electronic parts, automobile parts, office equipment parts, building material parts and the like.

[Examples] The present invention will be described in detail below with reference to Examples.

The measuring methods of the main characteristics are as follows.

Flowability: Melt viscosity (unit: poise) of the pellet after drying at 130 ° C. for 4 hours was measured under the following conditions using a Koka type flow tester.

Temperature: 260 ° C. when polyester is polybutylene terephthalate, 270 ° C. when polyester is polyethylene terephthalate Load: 100 Kg / cm ² nozzle; 1 mm length × 10 mm length Measured after 5 minutes have passed after reaching the predetermined temperature.

Impact strength: ASTM standard D-256 (with Izod notch) Tensile strength: ASTM standard D-638 Local viscosity: Measured at 35 ° C using O-chlorophenol as a solvent.

Examples 1 to 3, Comparative Examples 1 and 2 53.3 parts by weight of dried polybutylene terephthalate pellets having an intrinsic viscosity [η] of 0.85, and a total amount of polytribromostyrene and tribromodioctyl phthalate of 11 parts by weight (tribromodioctyl). The weight ratio of phthalate / polytribromostyrene was changed as shown in Table 1), 5 parts by weight of antimony trioxide, glass fiber 3 having a diameter of 10 μm and a length of 3 mm.
0 parts by weight, 0.2 parts by weight of phosphorus stabilizer, and 0.5 parts by weight of release agent are mixed in a V-type blender for about 2 minutes, supplied to a 65 mm diameter extruder, and pelletized at a cylinder temperature of 260 ° C for molding. A pellet for use was obtained.

After drying these pellets at 130 ℃ for 4 hours, using an injection molding machine, cylinder temperature 250 ℃, injection pressure 800 Kg / mm ² , mold temperature 70 ℃, molding cycle 15 seconds for impact strength test and tensile strength test I got a test piece.

Table 1 shows each characteristic value and melt viscosity evaluated by using this test piece.

It is clear that good flowability and good mechanical properties are obtained only when the ratio of brominated dioctyl phthalate to brominated polystyrene is within the scope of the invention.

Comparative Example 1 has good mechanical properties but high melt viscosity and poor flowability. Comparative Example 2 has good fluidity but poor mechanical properties.

Examples 4-6, Comparative Examples 3-4 53.2 parts by weight of dried polyethylene terephthalate pellets having an intrinsic viscosity [η] of 0.71 and 10 parts by weight of polytribromostyrene and tribromodioctyl phthalate in total (polytribromostyrene). And the weight ratio of tribromodioctyl phthalate were changed as shown in Table 2), 4 parts by weight of sodium antimonate, 2 parts by weight of methyl ether of polyethylene glycol having a molecular weight of 1000, 0.3 part by weight of bisphenol A type diepoxy compound, sodium montanate. 0.5 parts by weight and 30 parts by weight of glass fiber were mixed by a V-type blender for about 2 minutes, and this was supplied to an extruder having a diameter of 65 mm and pelletized at a cylinder temperature of 280 ° C. to obtain pellets for molding.

Cylinder temperature of 280 with injection molding machine using these pellets
℃, injection pressure 800Kg / cm ² , mold temperature 80 ℃, molding cycle 2
At 0 seconds, test pieces for impact strength test and tensile strength test were obtained.

Table 2 shows each characteristic value and melt viscosity evaluated by using this test piece.

Only when the ratio of brominated dioctyl phthalate to brominated polystyrene is within the range of the present invention, a resin composition satisfying both fluidity and mechanical properties can be obtained.

[Effects of the Invention] As described above, it is clear that the composition of the present invention has excellent fluidity during molding without impairing the excellent mechanical properties of the polyester resin.

Claims (3)

[Claims] 1. Brominated dioctyl phthalate 3 to 40% by weight
A flame-retardant polyester resin composition containing a flame-retardant agent containing 97 to 60% by weight of brominated polystyrene. 2. The flame-retardant polyester resin composition according to claim 1, wherein the polyester is polyethylene terephthalate, polybutylene terephthalate or a mixture thereof. 3. The flame-retardant polyester resin composition according to claim 1, wherein the brominated dioctyl phthalate is tribromodioctyl phthalate.