JPS6136538B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention uses a composite flame retardant consisting of magnesium oxide, which is not expected to have a flame retardant effect by itself, and a known flame retardant inorganic compound, to create a flame retardant thermoplastic that can achieve an unexpectedly improved flame retardant effect. The present invention relates to a resin composition. More specifically, 100 parts by weight of a thermoplastic resin, at least one inorganic compound selected from the group consisting of magnesium hydroxide, basic magnesium carbonate, and hydrotalcites, and about 1 to about 100 parts by weight based on the weight of the inorganic compound. The present invention relates to a flame-retardant thermoplastic resin composition containing about 20 to about 150 parts by weight of a composite flame retardant comprising 10% by weight of magnesium oxide. It is well known that the above-mentioned inorganic compounds impart a flame retardant effect to thermoplastic resins. However, in order to impart a flame retardant effect that satisfies V-1 or higher according to the UL standard, it is necessary to incorporate a considerable amount of the inorganic compound, and along with this,
There is a problem in that the desired mechanical properties inherent in the thermoplastic resin, particularly impact strength, elongation, etc., are deteriorated to a considerable extent, and furthermore, the suitability for melt molding of the resin composition is reduced. In order to improve such inconveniences and troubles, many attempts have been made to add various flame retardant auxiliaries to reduce the amount of flame retardant inorganic compounds (for example, Japanese Patent Application Laid-Open No. 1989-1999). -148447, JP-A-51-46341, JP-A-52-50342, JP-A-53
-12940, Japanese Unexamined Patent Publication No. 53-58548). However, when these flame retardant auxiliaries are used in combination, coloring due to the flame retardant auxiliary, toxicity of the auxiliary itself, gas generation due to thermal decomposition of the auxiliary during molding, deterioration of moldability, and/or flashing of the surface of the molded product may occur. There were other problems such as pattern formation. The present inventors conducted research on the use of the flame retardant inorganic compound that can avoid these difficulties. As a result, the effect of imparting flame retardancy is not expected by itself, and therefore, the filler may be used as an inorganic filler for flame retardant resin compositions to the extent that the flame retardant effect is not significantly reduced. Magnesium oxide (e.g., JP-A No. 53-54243), which has only been recognized as It was discovered that it showed an effect-enhancing effect. Furthermore, the disadvantages of the conventional auxiliary agents mentioned above are avoided, and since magnesium oxide itself is non-toxic and is a white substance that does not undergo thermal change, it does not color the resin and is easy to use during kneading and mixing. It does not cause thermal decomposition during molding and does not cause deterioration of the appearance of the molded product or decrease in mechanical strength, and is relatively inexpensive, so it is economical and has no harmful effects during molding or when burned. It is possible to achieve favorable improvement effects in terms of safety without the generation of gas or smoke, and furthermore, it is possible to achieve such improvements and flame retardant effect increasing effects by using a reduced amount of flame retardant inorganic compounds. It's been found. Therefore, an object of the present invention is to overcome the disadvantages of deterioration in moldability and physical properties due to the use of known inorganic flame retardants,
Another object of the present invention is to provide a flame-retardant thermoplastic resin composition that can provide an excellent improved flame-retardant effect with a reduced amount of the flame retardant used. The above objects and many other objects and advantages of the present invention will be apparent from the following description. The magnesium-containing inorganic compound selected from the group consisting of magnesium hydroxide, basic magnesium carbonate, and hydrotalcites used in the present invention can be used alone or in combination. These have a BET specific surface area of approximately 20 m ² /g ~
It is preferably in the range of about 1 m ² /g, and further,
Those having a secondary particle size in the range of about 0.1 to about 10μ and an average secondary particle size in the range of about 0.1 to 5μ are preferably used. The above hydrotalcites have the formula Mg _1-x Al _x (OH) ₂ (CO ₃ ) _x/2・mH ₂ O [however,
It is preferable to use those expressed as 0.1<x<0.4, 0<m<1]. In the present invention, the inorganic compound flame retardant as described above is preferably one that has been surface-treated with an anionic surfactant that helps improve compatibility with the thermoplastic resin. Through such treatment, the inorganic compound flame retardant coated with the anionic surfactant has improved dispersibility in the thermoplastic resin and shows more favorable results. Examples of such anionic surfactants include:
The following formula, RCOOM, where R is an alkyl group, preferably C ₈ -
Alkali metal salts of higher fatty acids represented by the following formula, ROSO ₃ M, where R _and M have the same meanings as above; Alkyl sulfate salts represented by the following formula, RSO ₃ M where R and M have the same meanings as above; Alkyl sulfonate salts represented by the following formula, R-aryl-SO ₃ M where R and M are Same as above, "aryl" represents an aromatic group such as benzene, toluene, naphthalene, alkylaryl sulfonate salts represented by the following formula: However, in the formula, R and M have the same meanings as above, and a sulfosuccinate ester salt represented by;
For example, Specific examples of these anionic surfactants include:
For example, sodium stearate, sodium oleate, potassium oleate, potassium palmitate, sodium laurylbenzenesulfonate, sodium N-methyl-N-oleoyl taurate (IgeponT()), potassium octadecylsulfonate, disodium 2 Examples include surfactants such as -sulfoethyl 2-sulfostearate and sodium butylnaphthalene sulfonate. In the present invention, the magnesium oxide used together with the inorganic compound flame retardant in a specific amount range is preferably in the form of fine powder, for example, the average secondary particle size is about
Those in the range of 0.1 to 10μ are preferably used.
Magnesium oxide can also be used by being coated with an anionic surfactant such as those exemplified above, and is preferred for improving dispersibility in thermoplastic resins. Surface treatment with an inorganic compound flame retardant using a surfactant as described above can be performed by the following means. Surface treatment of an inorganic compound flame retardant with an anionic surfactant can be carried out, for example, by suspending the powder of the inorganic compound flame retardant in water and adding an aqueous solution containing an anionic surfactant to a sufficiently stirred system. about 30
This can be done by stirring thoroughly for minutes to several hours. The temperature of the aqueous solution used here is higher than the temperature at which the anionic surfactant completely dissolves.
Perform surface treatment. Alternatively, powder of an inorganic flame retardant may be added to an aqueous solution of an anionic surfactant. After surface treatment, washing, dehydration, and drying can be performed. Further, the treatment of magnesium oxide with an anionic surfactant can be carried out by, for example, mixing magnesium oxide with an acid type anionic surfactant such as stearic acid in an amount of about 1 to about 10% by weight based on the magnesium oxide, using a Henschel mixer or a naphtha mixer. After thoroughly mixing with a mixer such as
This can be done by pulverizing stearic acid with an atomizer or the like to melt the stearic acid and chemically adsorb it onto the surface of magnesium oxide. In the above, the flame retardant aid effect of magnesium oxide is about 1 to about 10
It is demonstrated by using parts by weight. If the amount is less than this, the flame retardant effect will be extremely small, and if it is more than this, no substantial improvement in the effect is expected and the mechanical properties will be deteriorated. In the composition of the present invention, at least about 20 to about
150 parts by weight and magnesium oxide as described above,
Preferably, for the inorganic compound, about 1 to about
Contain 10 parts by weight. Examples of thermoplastic resins blended with the composite flame retardant of the present invention include ethylene, propylene, butene-1
Polymers or copolymers of other α-olefins; copolymers of one or more of such α-olefins and conjugated or non-conjugated dienes; polystyrene or styrene copolymers, e.g. Examples include ABS resin; polyamide resin; polyester resin; polycarbonate resin. There are no particular restrictions on the method of blending these thermoplastic resins and the composite flame retardant, and any means that can uniformly mix these additives into the resin, such as extrusion mixing or roll mixing, may be used. It can be carried out. Compounding can be carried out at any temperature below that which causes thermal degradation of the resin. Molding the flame-retardant thermoplastic resin composition of the present invention includes:
This can be done by any melt-molding method, such as injection molding or extrusion molding. The resin composition of the present invention may further contain additives such as a heat stabilizer, an ultraviolet absorber, a lubricant, and a pigment. Aspects of the present invention will be explained in detail below with reference to Examples. Example 1 Polypropylene (MI2), BET specific surface area 7m ² /
g, magnesium hydroxide with an average secondary particle size of 1.5M and magnesium oxide with an average secondary particle size of 2μ are mixed in the compounding ratio shown in Table 1 below, melted and kneaded in an extruder at 200°C, and then injection molded. A combustion test was conducted. The results are shown in Table 1. Comparative Example 1 Using polypropylene and magnesium hydroxide or magnesium oxide used in Example 1,
Test pieces were prepared in the same manner as in Example 1 according to the compounding ratios shown in Table 1, and a combustion test was conducted. The results are shown in Table 1 below, along with the results of Example 1 (1-1 to 1-3).

[Table] Example 2 Magnesium hydroxide and magnesium oxide used in Example 1 and various thermoplastic resins listed in Table 2 below were blended at the blending ratio shown in Table 2, and melt-kneaded using an extruder. Table 2 shows the combustion test results for injection molded products. Comparative Example 2 A test prepared in the same manner as in Example 2 by blending the various thermoplastic resins and magnesium hydroxide used in Example 2 according to the compounding ratio shown in Table 2 without using magnesium oxide. A combustion test was conducted on the pieces. The results are shown in the second section along with the results of Example 2.
Shown in the table.

[ _{Table] Example 3 Polypropylene (MI2), hydrotalcite compound [Mg 0.67 Al 0.33 ( OH ) 2} (CO ₃ ) _{0.165 .}
0.49H ₂ O (BET specific surface area 13 m ² /g, average secondary particle size 0.5μ)] and magnesium oxide with an average secondary particle size of 0.6μ were melted using an extruder at the compounding ratio shown in Table 3 below. Table 3 shows the results of combustion tests conducted on the kneaded and injection molded products. Example 4 In Example 3, except that basic magnesium carbonate with a BET specific surface area of 10 m ² /g average secondary particle size of 2 μm was used instead of the hydrotalcite compound.
By the same method, molded products were obtained with the compounding ratios shown in Table 3. The combustion test results are shown in Table 3. Example 5 2 kg of magnesium hydroxide powder with a BET surface area of 6 m ² /g and an average secondary particle size of 0.8 μ was added to warm water at about 80°C at about 20°C, and after thorough stirring, 40 g of sodium stearate was dissolved in this system. did. At about 2, add a hot aqueous solution at about 80°C, and then stir thoroughly for about 30 minutes to chemically adsorb sodium stearate onto the surface of magnesium hydroxide. After that, it is thoroughly washed with warm water at about 80°C, dehydrated, and dried at about 120°C. BET
2 kg of magnesium oxide having a specific surface area of 8 m ² /g and an average secondary particle size of 1 μm and 50 g of stearic acid were mixed for about 30 minutes in a Henschel mixer, and then finely pulverized in an atomizer. The surface-treated magnesium hydroxide and magnesium oxide obtained by the above method were melt-kneaded together with polypropylene in the mixing ratio shown in Table 3 using an extruder, and then injection molded. The results are shown in Table 3.

【table】

Claims (1)

[Scope of Claims] 1. 100 parts by weight of a thermoplastic resin, at least one inorganic compound selected from the group consisting of magnesium hydroxide, basic magnesium carbonate, and hydrotalcites, and about 100 parts by weight based on the weight of the inorganic compound. 1
A flame-retardant thermoplastic resin composition comprising about 20 to about 150 parts by weight of a composite flame retardant comprising ~10% by weight of magnesium oxide. 2. The resin composition according to claim 1, wherein the inorganic compound is surface-treated with an anionic surfactant. 3. The resin composition according to claim 1, wherein the magnesium oxide is surface-treated with an anionic surfactant. 4 The BET specific surface area of the inorganic compound is approximately 20 m ² /g ~
Claim 1 or 2 which is approximately 1 m ² /g.
The resin composition described in . 5. Claim 1 or 2, wherein the average secondary particle diameter of the inorganic compound is in the range of about 0.1 to about 5μ.
The resin composition according to item 1 or 4. 6 The average secondary particle size of the magnesium oxide is approximately
4. A resin composition according to claim 1 or 3, which has a particle size in the range of 0.1 to about 10μ.