JPS6057457B2 - Inorganic flame retardants and resin compositions for thermoplastic resins - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an inorganic flame retardant for thermoplastic resins that has excellent dispersibility in resins, non-aggregation properties, moldability, excellent physical properties such as impact strength, and excellent appearance of molded products. The present invention relates to a magnesium hydroxide-type inorganic flame retardant that has particularly excellent properties in terms of improving properties and flame retardancy, and to a flame-retardant thermoplastic resin composition containing an amount of such an agent in a specific range.

More specifically, magnesium hydroxide has a BET specific surface area of about 20 or less, preferably about 1 to about 10, and a BET specific surface area/plain method specific surface area ratio of about 1 to about 3. The present invention relates to an inorganic flame retardant for thermoplastic resins.

According to the present invention, there is provided a flame-retardant thermoplastic resin composition containing about 50 to about 25 parts by mass of the flame retardant per 1 part by weight of the thermoplastic resin, using the inorganic flame retardant. can do. Conventionally, it has been known to utilize magnesium hydroxide as a flame retardant or flame retardant filler for thermoplastic resins.

Various proposals have been made for magnesium hydroxide suitable for such purposes. For example, JP-A-5
No. 1-82334 has a melt index of 10 to 0.
To prevent poor appearance, especially the occurrence of silver streaks, in extrusion or injection molding of a white liquor resin composition containing 55 to 25% by weight of a thermoplastic resin for 19/m and 45 to 75% by weight of magnesium hydroxide. , specific surface area is 4
Proposals have been made to use magnesium hydroxide of 5 dIfl or less.

For example, in JP-A No. 52-59643, the bulk density is 0.35 to 0.70 da lcc and the specific surface area is 10 to 3.
0dly, and the ratio of the crystallite thickness in the direction perpendicular to the [110] plane in the crystal lattice to that of the [001] plane is 1.
．． The use of magnesium hydroxide with a molecular weight of 7 to 2.7 has been proposed. Furthermore, in Special Publication No. 52-43663,
It has been proposed to use magnesium hydroxide having an average particle size of 15 μm or less, an oil absorption of 50 mU9 or less, and an activity value of 30 m Uy or less.

The applicant of the present application has also conducted research for many years to develop magnesium hydroxide, which is excellent as an inorganic flame retardant for thermoplastic resins. Then, he succeeded in developing magnesium hydroxide with a new structure, and published JP-A-52-11579. proposed at. As a result of further research, we found that, depending on the identification factors such as those proposed above, which have traditionally been used to identify such magnesium hydroxide, it has excellent dispersibility in resins, non-agglomeration, In terms of moldability, excellent physical property imparting ability, ability to improve molded product appearance, flame retardancy, etc., it is not possible to combine particularly excellent properties. It has been discovered that along with the surface area, the ratio of BET specific surface area/plain method specific surface area acts as a very important factor.

As a result of further research based on this discovery, it was found that the BET specific surface area is about 20 dIy or less, preferably about 1 to about 10 dIy.
It has been discovered that magnesium hydroxide having a BET specific surface area/plain method specific surface area ratio in the range of about 1 to about 3 is extremely useful for combining the above-mentioned particularly excellent properties. Furthermore, the strain in the <101> direction in the X-ray diffraction method disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 1157-1980 is 3.
．． 0x10-3 or less, preferably has a crystal particle size in this direction exceeding 800A, and more preferably has a BET specific surface area of 20 mm, depending on its manufacturing method, the above-mentioned present invention may be applied. does not satisfy the ratios specified in the invention and therefore does not have the above particularly excellent properties. Achieving a combination of quality has proven difficult. For example, even if magnesium hydroxide has the new structure disclosed in this proposal, it cannot be obtained unless ammonia and slaked lime are used as alkali raw materials in the production method disclosed in this proposal. Even if the BET specific surface area obtained is less than 20 BoIy, the ratio of BET specific surface area/plain method specific surface area is as high as about 3.1 to 73, and it is easily a flame retardant that combines the above-mentioned particularly excellent properties. and when slaked lime is used, the proposal lacks concrete recognition and the above ratio is 1.
It has been discovered that magnesium hydroxide of ~3 can be formed. It has been discovered that nesium hydroxide having a ratio of 1 to 3, which is completely unrecognized in any of the conventional proposals, is particularly useful for combining the above properties. Furthermore, as disclosed in JP-A No. 51-82334, concentrated bittern or a magnesium hydroxide additive serving as a seed is stirred vigorously when adding an alkali hydroxide such as caustic soda or calcium hydroxide. Magnesium hydroxide produced by adding the magnesium hydroxide to 60 to 100°C, preferably 70 to 80°C for a long time, or the method disclosed in JP-A No. 52-59643 mentioned above. Thus, magnesium ions in seawater or bittern can be extracted with an alkali, such as calcium hydroxide, caustic soda, potassium hydroxide, lithium hydroxide, aqueous ammonia, particularly preferably caustic soda or calcium hydroxide. This is precipitated as
In this case, the amount of alkali used is 95 to 100%, with the equivalence point being 100% to the magnesium ions in seawater or bittern.
In the conventionally proposed magnesium hydroxide, such as the magnesium hydroxide formed by maintaining the concentration within the range of 125%, and in addition, in the conventional commercially available magnesium hydroxide, both the above-mentioned BET specific surface area and the above-mentioned ratio specified in the present invention are We cannot provide magnesium hydroxide that satisfies the requirements.

The BET specific surface area specified in the present invention is approximately 20r! 1Ig
Hereinafter, preferably about 1 to about 10 dIy and the ratio of BET specific surface area/plain method specific surface area is in the range of about 1 to about 3,
It has been discovered that magnesium hydroxide, preferably having a molecular weight of 1 to 2.8, more preferably 1 to 2.5, specifically possesses a high degree of the improved properties.

Therefore, the object of the present invention is to provide these materials which are particularly excellent in terms of excellent dispersibility in resins, non-agglomeration, moldability, excellent ability to impart physical properties, improved appearance of molded products, and flame retardancy. The object of the present invention is to provide a magnesium hydroxide flame retardant for thermoplastic resins that can have both properties.

Another object of the present invention is to provide a flame-retardant thermoplastic resin composition that has the above-mentioned properties.

The above objects as well as many other objects and advantages of the present invention will become more apparent from the following description. The inorganic flame retardant for thermoplastic resins of the present invention has a BET specific surface area of about 20 d1y or less, preferably about 1 to about 10 d1y, and a BET specific surface area/plain method specific surface area ratio of about 1 to about 3, preferably 1 to 2.8, more preferably 1-2.5
It consists of magnesium hydroxide.

The magnesium hydroxide is disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 52-11579.
Magnesium hydroxide having a novel structure described in 9 can be prepared by a method using ammonia or slaked lime as an alkaline substance, and the magnesium hydroxide obtained in this method satisfies the above requirements. You can select and use it. The details of the above manufacturing method will be omitted because it would be unnecessary to repeat them here, but they will be summarized below. The following formula can be formed by bringing magnesium chloride or magnesium nitrate into contact with ammonia or calcium hydroxide in an aqueous medium under conditions that allow sufficient contact between them, for example under stirring conditions, where A is C1 or NO3, x is a number of O<X<0.2, and m is a number of O to 6.

The above magnesium hydroxide can be produced by heating basic magnesium chloride or nitrate represented by the following formula in an aqueous medium under pressurized conditions.

The formation of the basic magnesium chloride or nitrate is carried out, for example, at a temperature of from about 0 to about 50'C, preferably from about 10 to
This can be done at about 20°C. The reaction is preferably carried out by adding an alkaline substance selected from the group consisting of ammonia and calcium hydroxide to an aqueous solution of magnesium chloride, magnesium nitrate, or magnesium chloride and calcium chloride under stirring conditions. ]
Magnesium chloride (acting in the form of NH4OH in the case of ammonia) or magnesium nitrate [Mg2+
This can be carried out by adding the equivalent ratio of alkali to ] so as to satisfy the following relationship. However, only when ammonia is used, the equivalent ratio may exceed 0.95. On this occasion,
It is preferable to carry out the reaction under conditions where chlorine or nitrate ions are sufficiently present. The basic monomagnesium chloride or nitrate that can be formed as described above is also a compound that has not been described in the literature prior to the disclosure in the above proposal.

The magnesium hydroxide utilized in the present invention is prepared by adding the basic magnesium chloride or nitrate obtained as described above to an aqueous medium under pressurized conditions as detailed in the proposal. It can be obtained by heating under a pressure of preferably about 5 k91 cr or more, for example about 5 to about 30 k91 cr, for example heating to about 150 to about 250°C. The magnesium hydroxide obtained in this way and the previous ET specific surface area conditions and BET specific surface area/
Magnesium hydroxide that satisfies both the plain method specific surface area ratio conditions can be used in the present invention. In addition, in the present invention, the plain method specific surface area and the BET specific surface area are as follows.

Plain method specific surface area: Measured and determined according to JISR52Ol-1964.

However, the porosity is set to 0.714, and the sample amount corresponding to that is measured. BET specific surface area: "Catalyst" VOl. 2, N
O. 4, 473 (1960) by Noriyuki Takagi. by.

In the present invention, in particular, BET specific surface area conditions and BET specific surface area / By selecting a ratio condition of the plain method specific surface area that satisfies the requirements of the present invention, it is possible to provide an inorganic flame retardant for thermoplastic resins and a resin composition that have both of the above-mentioned outstanding properties.

As shown later with many comparative examples together with Examples, the superiority of the present invention can be achieved by using magnesium hydroxide whose ratio does not satisfy the conditions of the present invention even if it satisfies the BET specific surface area conditions. Such improvements are difficult to achieve. Magnesium hydroxide used in the present invention, which satisfies both the BET specific surface area condition and the BET specific surface area/plain method specific surface area ratio condition, has a plate-like crystal shape and a crystal particle size (diameter) of approximately 0. .1~10μ, preferably 0.5~5μ゛(
be. The crystal particle size is larger when ammonia is used than when slaked lime is used as the alkaline substance.
Dispersion l is better. In addition to using the magnesium hydroxide used in the present invention as it is, by surface treating it with an anionic surfactant, the compatibility and dispersibility with resin can be further improved, and the moldability and molded products can be improved. can give favorable results by improving the physical properties of

For example, the magnesium hydroxide powder described above is added to an aqueous solution of an anionic surfactant such as a stearic acid leader under sufficient stirring conditions, or sodium stearizate is added to a suspension of the magnesium hydroxide powder. The anionic surfactant can be chemically adsorbed onto the surface of the magnesium hydroxide used in the present invention by adding an aqueous solution under sufficient stirring conditions. The amount of surfactant to be adsorbed is from about 0.1 to
Approximately 1 slag weight is good. The anionic surfactant used for the above surface treatment has the formula RCOOM (wherein,
R represents a C3-C4O alkyl group, M represents an alkali metal atom); a higher fatty acid alkali salt represented by the formula ROSO3M (wherein R and M have the same meanings as above); an alkyl sulfate represented by the formula ROSO3M; Alkyl sulfonate represented by (wherein R and M have the same meanings as above):
Alkylaryl sulfonic acid salts represented by the formula R-Aryl-SO3M (wherein R and M are as defined above): and sulfosuccinate ester salts represented by the formula (wherein R and M are as defined above) etc. can be exemplified. Specific examples of such surfactants include sodium stearate, potassium stearate, sodium oleate, potassium oleate, sodium palmitate, potassium palmitate, leader laurate, potassium laurate, potassium behenate, and uralylbenzene. Sodium sulfonate, otadecyl nitrate 1
Sodium octalauryl sulfonate, disodium ●2-sulfoethyl ●α-sulfostearate, sodium-N-
Examples include methyl-N-oleoyl taurate. In the composition of the present invention, about 50 to 10 parts of the magnesium hydroxide specified in the present invention, with or without surface treatment with an anionic surfactant, is added to 10 parts of the synthetic resin.
Add 250 parts by weight.

Examples of thermoplastic synthetic resins used in such compositions include. For example, polymers or copolymers of ethylene, propylene, butene-1 and other α-olefins;
Copolymers of one or more of such α-olefins and conjugated or non-conjugated dienes; polystyrene or styrenic copolymers such as ABS resins; polyesters or copolyesters; polycarbonate resins, Polyvinyl chloride, various rubbers such as EP
Examples include D-rubber and polyamide. In particular, non-polar to weakly polar thermoplastic resins are preferred. There are no special restrictions on the method of blending these thermoplastic resins and magnesium hydroxide, and any means that can uniformly mix these additives into the resin, such as extrusion mixing or roll mixing, can be used to mix the resin. It can be carried out at any temperature below that which causes thermal degradation. Molding can be performed by injection molding, extrusion molding, or the like. The flame retardant thermoplastic resin composition of the present invention can further contain other common additives. Examples of such other additives include fillers such as asbestos, fiberglass, talc, mica, ballastonite, calcium silicate, aluminum silicate, calcium carbonate; carbon black, phthalocyanine, quinacridone, etc. Coloring agents such as ndrine, azo pigments, titanium oxide, cadmium pigments, yellow lead, and Bengara; Antioxidants such as di-t-butyl-p-cresol, distearylthiodipropionate, dilaurylthiodipropionate ; Lubricants such as calcium stearate, zinc stearate, butyl stearate, ethylene bisstearamide; 2-hydroxy-4-octoxybenzophenone, 2(2″-hydroxy-5-methylphenyl)benzotriazole, ethyl-2- Examples include ultraviolet absorbers such as cyano 3●3-diphenylacrylate.The amount of these additives can be selected as appropriate; for example, about 10 to about 10 parts by weight of synthetic resin. about 0.1 to about 1 part by weight of colorants, about 0.1 to about 10 parts by weight of antioxidants, about 0.1 to about 5 parts by weight of lubricants. , about 0.1~
For example, the amount of the ultraviolet absorber may be about 1 part by weight. Hereinafter, several embodiments of the present invention will be explained in more detail with reference to examples and comparative examples.

In addition, in the following examples, in addition to the inorganic flame retardant of the present invention, resin compositions containing the flame retardant are also described for reference in order to demonstrate its effect as a flame retardant.

Example 1 Using ammonia as an alkaline substance, 2[0H
]/Mg2+=0.95, and then 1
Hydrothermal treatment was performed in an autoclave at 60° C. for 6 hours.

The obtained magnesium hydroxide was washed with water, dehydrated and dried, and pulverized. After mixing this with polypropylene, it was melt-kneaded at about 220° C. using an extruder to make pellets. This was molded using an injection molding machine. The results are shown in Table 1 below.

Example 2 2 kg of washed magnesium hydroxide obtained in Example 1
was suspended in about 20 y of water, heated to about 80°C, and then mixed with about 8 y of sodium stearate under sufficient stirring.
Solution 1' at 0°C was added and stirred for about 3 minutes.

Thereafter, it was dehydrated, dried, and pulverized, and the same operations as in Example 1 were performed to produce a molded product. The results are shown in Table 1 below. Example 3 Powdered slaked lime was used as the alkaline substance, and 1.5ml of magnesium chloride was added to desalinated concentrated seawater (containing calcium chloride) at 125°C, 2*Machi0H]/Mg2+
Add at an equivalent ratio of 0.85 and stir thoroughly.

After that, it was subjected to hydrothermal treatment at 60° C. for 4 hours. After washing and dehydration, the surface was treated with sodium stearate in the same manner as in Example 2, and the fabrication was then carried out in the same manner as in Example 1. The results are shown in Table 1 below. Comparative Examples 1 to 3 Magnesium hydroxide for comparison shown in Table 1 below was
Since it is difficult to pass through the extruder as it is, stearic acid was used in Comparisons 1 to 3 at 1% by weight and 7% by weight, respectively.
, 3.5% by weight, and melted, kneaded, and molded in the same manner as in Example 1.

The results are shown in Table 1 below. Table 1 also shows the results of molding polypropylene in the same manner as Control Example 1. Examples 4 to 7 Magnesium hydroxide having the physical properties shown in Table 2 was mixed with oleic acid sorter (Example 4 and Comparative Example 4) and stearic acid sorter (
Example 5 and Comparative Example 5), sodium laurylbenzenesulfonate (Example 6 and Comparative Example 6), and NaN-methyl-N-oleoyl taurate (Example 7 and Comparative Example 7)
Propylene-ethylene copolymer (Example 4 and Comparative Example 4), high density polyethylene (Example 5)
and Comparative Example 5), HI grade polystyrene (Example 6)
and Comparative Example 6), 6-nylon (Example 7 and Comparative Example 7)
) were kneaded and granulated to make pellets, which were then injection molded.

Claims (1)

[Claims] 1. A BET specific surface area of about 20 m^2/g or less and a BE
A permanent flame retardant for thermoplastic resins comprising magnesium hydroxide having a ratio of T specific surface area/Blaine method specific surface area in the range of 1 to about 3. 2. The inorganic flame retardant according to claim 1, wherein the BET specific surface area is about 1 to about 10 m^2/g.