JP3030726B2 - Method for producing flame-retardant resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a flame-retardant resin composition. More specifically, the present invention relates to a method for producing a flame-retardant resin composition characterized by improving the blooming resistance of a product.

[0002]

2. Description of the Related Art Crystalline resins are widely used in the fields of automobiles, building materials, electric parts and the like in the form of injection molded articles, films, sheets and blow molded articles, taking advantage of their excellent properties. However, a resin which is an organic polymer has a drawback that it is extremely flammable, and there is an increasing demand for flame retardation as its use becomes widespread.

[0003] The flame retardancy of these organic polymers is achieved by (1) adding a flame retardant to the resin, (2) blending the flame retardant resin,
(3) It is performed by a method such as making a flame-retardant polymer by reaction with a flame-retardant monomer.

[0004] Among them, a method generally used is a method of adding a flame retardant to a resin, and many resins are used by this method. Examples of the flame retardant used therein include organic chlorinated compounds, brominated compounds such as halides, phosphoric acid esters, phosphites, phosphorus-containing compounds such as phosphorus, and water-containing inorganic compounds. Antimony oxide is commonly used. In particular, decabromodiphenyl ether, which is an organic halogen-based flame retardant, has a high flame-retarding effect and is widely used as a flame retardant for polyolefin-based resins.

[0005]

However, each of the flame-retardant resin compositions prepared by adding these flame retardants has disadvantages. For example, flame retardant resins prepared by adding decabromodiphenyl ether, an organic halogen-based flame retardant, are liable to blooming, and in particular, polyolefin resins suffer from poor workability due to plate-out during processing and bleeding during use. , Which is making the image of the product worse. Further, the phosphorus-based compound has a flame-retardant effect only for a specific resin, and has poor compatibility with the resin, and tends to cause blooming. Further, the water-containing inorganic compound is regarded as a promising non-halogen flame retardant, but not only has a small flame retardant effect but also significantly impairs the physical properties of the resin.

[0006] A number of methods have been proposed to improve the disadvantages of organic halides. For example, as a method for suppressing blooming, a method of adding a flame retardant having a polar group to the basic structure (for example, JP-A-61-168643), a method of brominating a relatively high molecular weight oligomer (for example, JP-B-57-26305).
However, even in the former case, the suppression of blooming is not perfect, and blooming occurs during use as a product, which often has the drawback of causing not only trouble but also extremely burning. The latter has the drawback that although the blooming is suppressed, the flame retardant effect is inferior.

[0007]

The present inventors have conducted intensive studies to develop a good flame-retardant resin composition. As a result, the polystyrene resin and the decabromodiphenyl ether were previously 10 to 90 wt% and 90 to 10 wt%, respectively. To 210-2
By blending 60 to 97 wt% of a polyolefin resin and 0.5 to 20 wt% of antimony trioxide with 2 to 30 wt% of a composition kneaded at 90 ° C.
It has been found that a flame-retardant resin composition having extremely excellent blooming resistance and thermal stability can be obtained.

Various polystyrene resins can be used in the present invention. The polystyrene resin used here can be a polystyrene, impact-resistant polystyrene, or other styrene copolymers such as styrene-acrylonitrile copolymer. There are no restrictions.

The amount of decabromodiphenyl ether added to the polystyrene resin used in the present invention is 10 to 90% by weight.
Preferably it is 20 to 80 wt%. Addition amount is 10wt
%, The amount of the masterbatch added increases and the physical properties of the product are impaired. If it exceeds 90 wt%, it is difficult to make a master batch.

The processing temperature for preparing the master batch is 210 to 290 ° C., preferably 230 to 270 ° C. If the processing temperature is lower than 210 ° C., the dispersion of the flame retardant becomes poor, and if the processing temperature exceeds 290 ° C., decomposition of the flame retardant and the resin starts.

The masterbatch can be prepared by mixing using a conventional mixing apparatus such as a Henschel mixer or a ribbon blender, and using a conventional single-screw extruder, twin-screw extruder or pressure kneader.

The amount of the flame-retardant masterbatch thus prepared varies depending on the required level of flame-retardancy, but is 2 to 30% by weight, preferably 4 to 30% by weight. When the amount is less than 2 wt%, the flame retardancy is poor, and when it exceeds 30 wt%, the physical properties of the polyolefin resin are deteriorated.

Various polyolefin resins can be used in the present invention. The polyolefin resin used here is polyethylene, polypropylene, and ethylene-
A vinyl acetate copolymer, a polyethylene-polypropylene copolymer, and a mixture thereof can be used. These resins are not particularly limited as long as they can be generally used for molding, and are not affected by melt index, density, type and amount of catalyst residue.

The amount of antimony trioxide added is strongly related to the amount of halogen added, and is preferably 0.5 to 20 wt%, more preferably 1 to 15 wt%. If the amount is less than this, no flame-retardant synergistic effect is observed. If the amount is more than this, physical properties of the resin deteriorate.

In the present invention, it is possible to use an inorganic flame retardant or a phosphorus flame retardant in combination, as long as the physical properties are not deteriorated.

In the present invention, those usually used as a flame retardant auxiliary, for example, zinc borate can be used in combination.
By adding these, flame retardancy is improved and glowing is suppressed.

In the present invention, physical properties can be improved by using an inorganic filler in combination. These purposes are usually
Talc, mica, silica, calcium silicate, glass fiber, carbon fiber, calcium carbonate and the like are used.

In the present invention, in addition to those described above, additives usually used as polyolefin resin additives, for example, antioxidants, light stabilizers, ultraviolet absorbers, and stabilizers can also be added.

The flame-retardant polyolefin resin composition thus obtained can be formed into a molded article by a commonly used processing method such as injection molding, extrusion molding, blow molding and the like.

[0020]

The present invention will be described in detail with reference to the following examples, but the present invention is not limited to these examples.
In addition, the various test methods implemented in the Example and the comparative example are as follows. -Flame retardancy test According to JIS K7201 "Combustion test method for polymer materials by oxygen index method". The test piece was prepared using an injection molding machine. -Plate-out test, blooming test A 100 x 65 x 3 mm flat plate was prepared using an injection molding machine. At this time, the presence or absence of a plateant was determined based on the degree of fogging of the mold. After the plate was heated in a gear oven at 100 ° C. for 168 hours, it was taken out and visually judged for blooming. -Thermal stability The test piece was placed in a gear oven at 150 ° C and heated for 30 days. The test piece was taken out, and its yellowness was measured with a colorimeter.

Example 1 Polystyrene resin (manufactured by Mitsubishi Monsanto Co., Ltd .; HF77)
40% by weight of general grade) and decabromodiphenyl ether (manufactured by Tosoh Corporation; frame cut 110R) 6
0% by weight, 0.1% by weight of 2,6-di-t-butyl-p-cresol (manufactured by Yoshitomi Pharmaceutical Co., Ltd .; Yoshinox BHT) and 0.1% by weight of calcium stearate were mixed with a Hensel mixer. The mixture was extruded at a resin temperature of 250 ° C. using a twin-screw kneading extruder having a diameter of 30 mmφ to produce pellets. The pellets were then 10% by weight, antimony trioxide 2% w
t% and polypropylene resin (manufactured by Tosoh Corporation; J70
90 impact-resistant grade) and mixed at a temperature of 210 ° C. using a twin-screw extruder as described above. The pellets were further cooled to a resin temperature of 23 using a 150 t injection molding machine.
Test pieces were prepared at 0 ° C. Table 1 shows the results. Blue
Both the stability and the thermal stability are extremely good.

Example 2 A 30% by weight master batch prepared in Example 1, 9% by weight of antimony trioxide and 61% by weight of a polypropylene resin were mixed to prepare a PP flame-retardant compound, and then a test piece was prepared in the same manner as in Example 1. It was created. Table 1 shows the results.
Both blooming and thermal stability are extremely good.

Example 3 In the same manner as in Example 1, a master batch was prepared by blending 20% by weight of polystyrene resin (manufactured by Mitsubishi Monsanto Co., Ltd .; HT88 impact grade) and 80% by weight of decabromodiphenyl ether. , This master batch 20
Specimens were prepared with a weight of 8% by weight of antimony trioxide and 72% by weight of a polypropylene resin. Table 1 shows the results. Both blooming and thermal stability are extremely good.

Comparative Example 1 In place of a previously prepared master batch, Example 1
A flame-retardant PP compound was prepared using the same amount of decabromodiphenyl ether as used in the above, and a test piece was prepared.
Table 1 shows the results. Poor blooming resistance.

Comparative Example 2 A test piece was prepared in the same manner as in Example 2 except that a polycarbonate resin (manufactured by Teijin Chemicals Ltd .; I-1250) was used as the base resin of the masterbatch. Table 1 shows the results. Poor blooming resistance.

Comparative Example 3 A test piece was prepared in the same manner as in Example 2 except that a polybutylene terephthalate resin (C7000N, manufactured by Teijin Limited) was used as the base resin of the masterbatch. Table 1 shows the results. Poor blooming resistance.

[0027]

As is apparent from the above description, the composition of the present invention has extremely low blooming resistance and thermal stability, which are the drawbacks of flame retarding a polyolefin resin with an organic halogen-based flame retardant. It is a good composition.

[Table 1]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI // (C08L 23/00 25:04)

Claims (1)

(57) [Claims] 1. A polystyrene resin of 10 to 90 watts in advance.
t% and decabromodiphenyl ether 90 to 10 wt
% Kneaded at 210 to 290 ° C.
A method for producing a flame-retardant resin composition comprising a polyolefin resin of 60 to 97 wt% and an antimony trioxide of 0.5 to 20 wt% mixed with 0 wt%.