JPS63156860A - Flame-retardant resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition having heat-decomposition resistance and hydrolysis resistance, free from emission of toxic gas and having excellent flame-retardancy, by compounding a combustible synthetic resin with modified red phosphorus particles surface-coated with a composite coating film of a titanium-cobalt compound. CONSTITUTION:Modified red phosphorus having a composite hydrated oxide of titanium and cobalt deposited on the surface of red phosphorus particles as a coating film is produced e.g. by dispersing red phosphorus particles (1-100mum in diameter) in an aqueous solution of mixture of a titanium salt and a cobalt salt, adding an alkali agent (e.g. ammonia gas) to the dispersion under agitation to control the pH to 6.5-8.5 and heating the mixture under heating. The sum of Ti and Co deposited on the phosphorus particle is 0.5-10wt% based on phosphorus. 100pts.wt. of a combustible synthetic resin (thermoplastic or thermosetting resin) is compounded with 0.5-50pts.wt. of the modified red phosphorus particles.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a flame-retardant resin composition, and in particular to a composite of a titanium-cobalt compound on the particle surface of a combustible synthetic resin such as a thermoplastic resin or a thermosetting resin. This invention relates to a flame-retardant resin composition containing modified red phosphorus coated with a film.

[Prior Art] Conventionally, the uses of various synthetic resin molded products have been expanding with increasing diversity, but at the same time, flame retardant requirements for the molded products have become increasingly strict.

It is well known that red phosphorus is used as a typical additive in making synthetic resins flame retardant.

However, since red phosphorus generates phosphine with an unpleasant odor when hydrolyzed, there is a problem in blending it as it is into a resin. Therefore, many proposals have been made for stabilized red phosphorus that is modified red phosphorus.

For example, the method of depositing aluminum hydroxide on red phosphorus surfaces using aluminum sulfate and sodium bicarbonate [Gmelin, Handbluff der Anorganischen Chemier, 8th edition (1964), Phosphorus, Part B, 8
Page 3 (G+*elin, 'Handbuchder
8
th Edition (1964), vol Phos
phorus, Parts B, Page 83)
] has been reported.

However, this red phosphorus modification method requires coating a large amount of aluminum hydroxide in order to completely stabilize red phosphorus, which not only reduces its effectiveness as a flame retardant, but also reduces the effectiveness of red phosphorus depending on the application. May cause adverse effects.

Other examples of methods for modifying red phosphorus include coating with a composite of aluminum hydroxide and zinc or magnesium hydroxide (U.S. Pat. No. 2,635,953), coating with thermosetting or curable resin. modified red phosphorus (Unexamined Japanese Patent Publication No. 51-10
No. 5996), modified red phosphorus in which the surface of red phosphorus was converted into a metal phosphide and then coated with a thermosetting resin (JP-A No. 52-1
No. 25489), modified red phosphorus whose red phosphorus surface is coated with a titanium water-conserving oxide (US Pat. No. 4,421,782)
2), or modified red phosphorus in which the surface of red phosphorus is coated with a hydrated oxide of titanium and then further coated with a thermosetting resin.

[Problems to be Solved by the Invention] As mentioned above, many proposals have been made for stabilizing red phosphorus through modification, but all of them have advantages and disadvantages, and still have some important problems. In particular, red phosphorus is easily hydrolyzed in the presence of moisture and is accompanied by the generation of phosphine gas, which is odorous and toxic even in a very small amount, so it is extremely difficult to completely suppress the generation of this gas.

In particular, thermoplastic resins require processing temperatures of 200°C or higher, sometimes exceeding 300°C, due to demands such as improved workability. However, since the above-mentioned phosphine gas was insufficiently suppressed, it could hardly be put to practical use.

In order to virtually completely suppress the generation of phosphine gas that accompanies the decomposition of red phosphorus, the present invention has conducted extensive research searching for various stabilization methods.
We discovered that surprisingly stable red phosphorus powder could be obtained by depositing a cobalt-based composite hydrated oxide.
The present invention was completed based on the finding that this can be effectively used not only for thermosetting resins but also for thermoplastic resins without sacrificing flame retardancy.

[Means for Solving the Problems] and [Operations] In other words, the gist of the present invention is to provide a modified flammable synthetic resin in which a titanium-cobalt complex hydrated oxide is deposited and coated on the surface of red phosphorus particles. This invention relates to a flame-retardant resin composition characterized in that it contains high quality red phosphorus.

The present invention will be explained in detail below.

The flammable synthetic resin that can be used in the present invention is a flammable synthetic resin that is required to be flame retardant when used, and may be either a thermosetting resin or a thermoplastic resin. Further, the combustible synthetic resin can be used, for example, as various molding materials, paints, adhesives, etc., and the manner is not particularly limited.

Examples of the thermosetting resin include phenol resin, urea resin, melamine resin, unsaturated polyester resin, epoxy resin, silicone resin, diacrylic phthalate resin, and polyurethane resin.

Examples of thermoplastic resins include polyethylene, polyalpha-olefins such as polypropylene, copolymers containing at least alpha-olefins with other polymers, polystyrene, methacrylic resins, styrene-acrylonitrile copolymers ( As resin), acrylonitrile-tutadiene-styrene resin (ABS resin), polyvinyl chloride, fluororesin, polyamide, polyimide, polycarbonate, polyacetal, thermoplastic polyester, cellulose acetate (cellulose resin), polysulfone thermoplastic polyimide, polyphenylene oxide, polysulfone Examples include butylene ionomer resin.

Next, the modified red phosphorus that is effectively blended into the flammable synthetic resin as a flame retardant is a titanium-cobalt complex hydrated oxidation product that is a hydrolysis product of soluble salts of titanium and cobalt on the surface of red phosphorus particles. A coating is formed by depositing substances.

This deposit appears to be TiO2.nH2O and Co-nH2O, but since it is a coprecipitate, it is presumed that it is not just a mixture of these.

In addition, the amount of titanium-cobalt-based composite hydrated oxide deposited on the red phosphorus particles varies depending on the use of the modified red phosphorus, etc., but in many cases Ti per total weight of the red phosphorus particles is
It is desirable that +co be in the range of 0.5 to 10% by weight, preferably 1 to 6% by weight.

The reason for this is that if the content is less than 0.5% by weight, the suppression of phosphine gas is incomplete, and if it exceeds 10% by weight, it is inappropriate from a practical standpoint.

The weight ratio of titanium and cobalt in the titanium-cobalt composite hydrated oxide is Ti:Co=1:0.
A value in the range of 1 to 0.5 is preferred.

By microscopic observation, it can be confirmed that the modified red phosphorus in the present invention has a deposited coating formed on the particle surface, and can be easily identified in comparison with the original red phosphorus.

The modified red phosphorus in the present invention is stabilized red phosphorus that almost completely suppresses the generation of phosphine gas, or the details of the suppression mechanism are unknown.

It is also not clear why the combination of titanium and cobalt shows good results.

This combination was discovered as a result of numerous experiments, and the combination of titanium and cobalt can produce unique effects that cannot be achieved by combining some of them with other elements.

The particles of red phosphorus in the present invention are at most 100 gm.
Below, and the average particle size is 5 to 30) zm,
Preferably, a range of 10 to 20 m is suitable.

Further, since fine powder increases the surface area of the particles and tends to become unstable, it is preferable to cut the particles with a particle size of about 11 zm or less as much as possible.

Therefore, it is preferable that the red phosphorus particles in the present invention have a particle size substantially in the range of 1 to 100)is, and even if particles with a particle size outside the above range are contained, the particle size is 11Lm or less and Content of 100gm or more is 5
It is desirable that the amount is less than % by weight. If the particle size is outside the above range, that is, if it is substantially less than 1 μm, the modified red phosphorus is likely to become unstable, and if it exceeds substantially 100 μm, the mixing state of the flammable synthetic resin will deteriorate. Undesirable.

Note that the particle size and average particle size are values measured by the Coulter counter method.

Next, the method for producing modified red phosphorus in the present invention is not particularly limited as long as it is as described above, but for example, it can be industrially advantageously prepared by the following method. .

First, red phosphorus is dispersed in a mixed salt aqueous solution of titanium salt and cobalt salt, and an alkali agent is added to the resulting red phosphorus suspension while stirring to neutralize it and adjust the pH to 6.5 to 8.5. do. After neutralization, the fine precipitates of the titanium-cobalt composite hydrated oxide are deposited on the surface of the red phosphorus particles by heating with stirring, followed by separation and recovery, which makes it industrially advantageous and homogeneous. can produce stable modified red phosphorus.

Note that the titanium salt and cobalt salt used in the preparation of the mixed salt aqueous solution may be used without any particular limitation as long as it is a salt of titanium and cobalt. It is preferable to use at least one selected from the following.

The concentration of the mixed salt aqueous solution of titanium salt and cobalt salt is not particularly limited as long as it is below the solubility of each group at room temperature, but it is usually 0.5 to 1.0% by weight as Ti and 0.5 to 1.0% by weight as Co.
It is preferably 0.05 to 0.2% by weight.

Alkaline agents include ammonia gas, aqueous ammonia, caustic sorter, caustic potash, NaHCO+, Na2GO, K
At least one selected from inorganic alkaline agents such as 2CO3, KHCO3, Ca(OH)2, and organic alkaline agents such as ethanolamine is used, but ammonia scum and ammonia can be easily removed by washing and removing by-products. Water is preferred.

Next, in the present invention, when the modified red phosphorus is used as a flame retardant for various flammable synthetic resins, the modified red phosphorus is used as P for 100 parts by weight of the flammable synthetic resin.
．． A range of 5 to 50 parts by weight, preferably 0.5 to 15 parts by weight is suitable.

Furthermore, the modified red phosphorus in the present invention can be used in combination with other inorganic or organic flame retardants.

Inorganic flame retardants include magnesium, aluminum,
Examples include hydroxides such as zirconium, antimony oxide, etc. Organic flame retardants include various phosphate esters,
It can be appropriately selected from phosphite esters, organic tin compounds, etc.

In addition, in the present invention, the flame-retardant resin composition may contain other resin additives that may be normally blended as necessary depending on the purpose of use, such as plasticizers, lubricants, stabilizers, fillers, colorants, and antioxidants. Alternatively, add UV inhibitors and the like as appropriate.

The flame-retardant resin composition according to the present invention can be used in various adhesives, paints, or molded products in fields where flame retardancy is required. It is suitable as

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

Examples 1 to 8 and Comparative Examples 1 to 16 (1) Preparation of modified red phosphorus Samples 1 to 6 Titanium sulfate solution (reagent Ti(SO4), as 24
．． 0wt% (manufactured by Kanto Kagaku Co., Ltd.) and cobalt sulfate (reagent, manufactured by Kanto Kagaku Co., Ltd.) were weighed in amounts shown in Table 1 below, and dissolved in 50 g of water. To this, particles with an average particle size of 2G were washed with water and vacuum dried (100℃) with a particle size of 3 to 44 pm.
Add 5g of pm red phosphorus powder and add 5wt% while stirring.
of ammonia aqueous solution was added to adjust pl to 7.5.

Next, heat with stirring to bring the temperature to 85°C, and heat for 2
The mixture was heated and stirred for an hour. The final pH at this time was 6.8. After cooling, it was separated from the furnace. Rinse the furnace slag with deionized water until the electrical conductivity of the liquid is below Lops/cm,
It was dried for 3 hours in a vacuum dryer at 120°C to obtain modified red phosphorus.

Sample 7 Titanium tetrachloride solution (8.5 wt% as Tj) 2.9
4 g (5 wt% as Ti relative to red phosphorus) and 0.12 g (0.5 wt% as CO relative to red phosphorus) of cobalt sulfate (CoSO4.7H20) were dissolved in 50 g of water.

Add to this red phosphorus that has been washed with water and vacuum dried (100°C)
Particle size: 3 to 44 gm, average particle size: 15 μm) was added, and while stirring, 5 wt% NaOH solution was added, and the pH was adjusted.
Adjusted to 8.0.

Next, the mixture was heated to a temperature of 85° C. and continued to be heated and stirred for 2 hours. The final pn at this time was 7.0. After cooling, it was separated from the furnace. The electrical conductivity of the furnace fluid is 1 by using deionized water.
It was washed until it showed 0 μs/cm or less and dried in a vacuum dryer at 120° C. for 3 hours to obtain modified red phosphorus.

Sample 8 Titanium tetrachloride solution (8.5 wt% as Ti) '1.7
6 g (3 wt% as Ti relative to red phosphorus) and 0.06 g (0.3 wt% as Go relative to red phosphorus) of cobalt chloride (Coci'2.6H20) were dissolved in 50 g of water.

Add to this red phosphorus that has been washed with water and vacuum dried (100°C)
Particle size: 3 to 44 gm, average particle size: 15 gm) was added, and while stirring, 5 wt% NH,OH solution was added, and p
n was adjusted to 7.5.

Next, the mixture was heated to a temperature of 85°C, and heating and stirring were continued for 2 hours. The final pH at this time was 6.8. After cooling, it was separated from the furnace. The slag was washed with deionized water until the electrical conductivity of the filtrate was 10 g5/cm or less, and dried in a vacuum dryer at 120° C. for 3 hours to obtain modified red phosphorus.

Comparative Samples 1 to 3 In Samples 2 to 4, the red phosphorus particles were coated using only a titanium sulfate solution without using cobalt sulfate. Other conditions were the same as in Samples 2-4.

The amount of titanium sulfate added is shown in Table 2 below.

Table 2 Comparative Samples 4 to 15 Red phosphorus coating was performed in the same manner as Sample 6 except that the cobalt sulfate in Sample 6 was replaced with various metal salts shown in Table 3 below. The types and amounts of metal salts added are shown in Table 3 below.

Comparative sample 16 Red phosphorus 100 with particle size 3-44pm, average particle size 15gm
g was suspended in 250 g of water to prepare a slurry of red phosphorus. Next, after adding 120 g of an 8 wt% aqueous solution of aluminum sulfate as AIhOz, the temperature was raised to 80 °C,
While stirring, a 10 wt% NaOII solution was added dropwise over 2 hours to adjust the pH to 5.6. Furthermore, heating and stirring were continued for 1 hour to deposit aluminum hydroxide on the surface of the red phosphorus particles.

After cooling and separating the furnace, the electric conductivity of the liquid is 20p, s/
After washing until it becomes less than 10 cm, put it in a vacuum dryer.
It was dried at 0°C for 5 hours to obtain modified red phosphorus.

(2) Preparation of resin composition A mixture of the following composition was mixed into a mold (12.7 mm x 12.7 m)
An epoxy resin molded article was prepared by pouring the mixture into a molded article (m x 127 mm) and heating and curing it at 100°C for 6 hours.

Also, regarding the presence or absence of phosphine odor during test piece preparation,
Detection tube (gastic detection tube: detection limit 0, O4ppm
(manufactured by Hokuyo Sangyo ■) was measured and detected.

Epoxy resin 10 parts by weight (Epicoat 828: oil-based shell epoxy ■ product) Anhydrous curing agent 8 parts by weight (8-donor: Japan Ciba Geigy ■ product) Aluminum hydroxide 10 parts by weight (Hisilite H32-I.

(manufactured by Showa Light Metal Company) Sample: 1 part by weight (3) as red phosphorus
Measurement method and results 1. Measuring the amount of phosphine emitted from each sample 0.5g of the sample was stored in a constant temperature and humidity chamber at a temperature of 30°C and a relative humidity of 83% for 48 hours, and heated in N2 gas (1.
50°C for 13 hours).

The amount of PH3 generated was measured using a gas chromatograph,
The amount of PH generated per 1 g of sample was converted into the amount (gg).

The results are shown in Table 4.

2. Flame resistance test The resin composition was measured according to the flame resistance test method A of JIS K-6911. The results are shown in Table 4. Note that the resin composition (blank) containing no red phosphorus was "flammable".

(4) Hot water test at branch office for modified red phosphorus In an Erlenmeyer flask equipped with a reflux condenser, add 1 g of modified red phosphorus sample and 1 g of water of each sample and comparative sample shown in Table 5 below.
80+ni) and heated at boiling for 8 hours. The pH and electrical conductivity of the supernatant were measured before and after heating. The results are shown in Table 5.

Table 5 Comparative Example 17 In the resin composition of Example 1, thermosetting resin-coated red phosphorus (commercial product A, itself has a phosphine generation amount of 5 ppm) and alumina-coated red phosphorus (commercial product B, itself) The amount of phosphine generated is 3 to 7 p.
An epoxy resin molded body was prepared in the same manner as in Example 1 except that pm+) was used, and the flame resistance test of the molded body was conducted.

As a result, all had a phosphine odor, and as a result of the measurement, 0.3 to 1.5 ppm of phosphine was detected.

Examples 9 to 17 Resin compositions (Table 6) in which predetermined amounts of metal hydroxide and modified red phosphorus (sample No. 2.3, 4, 5°7) were blended with 100 parts by weight of unsaturated polyester. 1 part by weight of a curing catalyst of 55% by weight of methyl ethyl ketone peroxide and an appropriate amount of cobalt naphthenate were mixed uniformly to form a mold (12.7 mm x 12.7
mm x 127 mm) and heated at 100°C for 2 hours to harden to prepare a polyester resin molded body.

No phosphine odor occurred during the preparation of this test piece.
Detection tube (gastic detection tube: detection limit 0, O4ppm
(manufactured by Hokuyo Sangyo ■) could not detect it.

Further, the obtained test piece was subjected to a heat resistance test using the measuring method shown in Example 1 above. The results are shown in Table 6.

Example 18 1,4-polybutadiene polyol (molecular weight 2800,
) Modified red phosphorus (sample No. 2) per 100 parts by weight
) 10 parts by weight, 50 parts by weight of zirconium hydroxide, N
, N-bis(2-hydroxypropyl)-aniline 15
Homogeneous mixture of parts by weight and 20 parts by weight of process oil 1
00 parts by weight and 15 parts by weight of modified liquid 4,4'-diphenylmethane diisocyanate (NGO equivalent: 145) were heated at 65°C for 114 hours to harden and give a test piece (
10n+m×10tm×100mm) was created.

In this preparation, no phosphine odor was produced at all, and no phosphine odor was detected in the measurement using a detection tube.

Next, the flame resistance of this test piece was measured by the measuring method shown in Example 1 above, and it showed good flame retardancy.

Examples 19 to 27 Various thermoplastic resin compositions having the formulations shown in Table 7 were prepared,
After heating at 180 to 270°C and kneading with two wooden rolls for 10 minutes, a test piece (12,7+mi+X 3 mmX 12.
7Iam) was prepared and a flame resistance test was conducted.

No phosphine odor occurred during the preparation of this test piece.
Detection tube (gastic detection tube: detection limit 0, O4ppm
, manufactured by Kitazawa Sangyo Co., Ltd.), it was not detected.

Further, a heat resistance test was conducted on the obtained test piece.

The results are shown in Table 7.

Comparative Example 18 Polypropylene resin was prepared in the same manner as in Example 20, except that the thermosetting resin coated red phosphorus (commercial product A) and alumina coated red phosphorus (commercial product B) were used as samples for the polypropylene in Example 20. A molded body was prepared, and a flame resistance test was conducted on the molded body.

As a result, all of them had a phosphine odor, and as a result of the measurement, 1 to 5 ppm of phosphine was detected.

[Effects of the Invention] As explained above, it has been found that the modified red phosphorus of the present invention exhibits heat decomposition resistance and hydrolysis resistance that were not available in the prior art. This titanium-component composite coating almost completely suppresses the hydrolysis reaction of red phosphorus in the presence of moisture and at high temperatures, thereby completely preventing the generation of toxic and foul-smelling phosphine gas.

This modified red phosphorus exhibits its flame retardant effect on combustible resins without sacrificing anything, so the flame retardancy of various synthetic resins blended with it is the same as conventional ones. It is excellent.

In particular, it is of great industrial significance that it is possible to make thermoplastic resins that require high processing temperatures flame retardant without causing any problems in the working environment.

Furthermore, when a large amount of modified red phosphorus with a high deposited coverage is blended into a resin, a characteristic resin composition having roughly flame-retardant properties can be obtained, and its use can be expected.

Claims (4)

[Claims] (1) A flame-retardant resin composition comprising a flammable synthetic resin mixed with modified red phosphorus in which a titanium-cobalt composite hydrated oxide is deposited and coated on the surface of red phosphorus particles. (2) The flame-retardant resin composition according to claim 1, wherein the flammable synthetic resin is a thermoplastic resin. (3) The flame-retardant resin composition according to claim 1, wherein the flammable synthetic resin is a thermosetting resin. (4) The flame-retardant resin composition according to claim 1, wherein the modified red phosphorus is blended in an amount of 0.5 to 50 parts by weight as P based on 100 parts by weight of the flammable synthetic resin.