JP2002371198A - Flame retardant resin composition blended with high purity zinc borate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flame retardant resin composition blended with a high purity zinc borate. SOLUTION: This resin composition is characterized by using the high purity zinc borate containing <=0.01% Na<+> and <=0.02% SO4 <--> as a resin flame retardant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame retardant containing zinc borate, and to a flame retardant resin composition obtained by blending the same with a resin.

[0002]

2. Description of the Related Art Conventionally, thermoplastic resins are excellent in moldability and mechanical properties and electrical properties. Therefore, in particular, halogen-based flame retardants such as tetrabromobisphenol A and decabromodiphenyl oxide are used. The compounded flame-retardant resin composition is widely used in various industrial fields such as, for example, machinery, electricity, construction, and transportation. In particular, a polyvinyl chloride resin composition containing a halogen-based flame retardant has been used widely in electric wire coating because of its excellent flame retardancy. However, such an electric wire coating is used, for example, in public facilities. Once burned, such as in underground facilities and the like, there is a risk of causing serious environmental problems due to the generation of toxic gases.

[0003]

2. Description of the Related Art Flame retardation of a resin has been attempted by using an organic halogen-based flame retardant alone or in combination with a halogen-based flame retardant and antimony trioxide. However, in recent years, demands for environmental protection and safety have increased, and inorganic flame retardants which are dehalogenated and deantimony and have low toxicity have been used. As halogen-free inorganic flame retardants, the use of metal hydroxides such as aluminum hydroxide and magnesium hydroxide, specific metal oxides, and boron-based metal compounds has been increasing year by year.

However, metal hydroxides such as aluminum hydroxide and magnesium hydroxide cannot be flame-retardant unless they are added in large amounts.
This solution is required because it requires a compounding of 0 parts by weight or more, and the strength is greatly reduced in electric wires and cables for which resin strength is required.

On the other hand, in a boron-based metal compound, 4ZnO.B
_{2 O 3 · H 2 O,} 2ZnO · 3B 2 O 3, BaO · B 2
O ₃ · _{H 2} is O the compound is used, among others thermal stability is good zinc borate _{2ZnO · 3B 2 O 3 · 3.5H} 2
The chemical formula of O is considered to be good. However, when used alone, the flame retardancy may be insufficient. At this time, the amount of addition is reduced by the synergistic effect of the combination of the above-described metal oxide, metal hydroxide, and zinc borate.

On the other hand, there is a demand for a flame retardant which contains a small amount of impurities in a resin for an electronic material and the like and has a small amount of ions eluted at a high melting temperature of the resin. In particular, alkali metal ions, halogen ions and the like are eluted in the resin. In such a case, problems such as deterioration of the resin and electronic components, deterioration of electric characteristics, deterioration of insulation characteristics, and the like occur.

Further, as a very small amount of impurities for electronic materials,
There is a demand for uranium and thorium with low contents of α-rays, which are one of the causes of malfunctions of electronic equipment circuits. Zinc borate also has this quality requirement. Until now, zinc borate, which is generally commercially available, contains a lot of eluting impurities, Na ⁺ is about 0.1%, SO ₄ ⁻⁻ is about 0.2%, so naturally the eluting ions are also large, and the amount of eluting ions such as PVC and epoxy resin is high. It is not at a level that can be used for material applications. Regarding the flame retardant effect, among the impurities, alkali metal ions,
In particular, it is known that Na acts to lower the melting point and decomposition temperature of a substance.

Therefore, the present inventors have conducted various studies, and as a result, have come to produce a high-purity zinc borate having significantly reduced impurities and high flame retardancy.

[0009]

SUMMARY OF THE INVENTION The present invention reduces the deterioration of the properties of the resin composition by using the above flame retardant materials such as metal oxides and metal hydroxides together with the zinc borate described in the claims, or by using them alone. And the flame retardant effect can be improved. Examples of the resin used in the present invention include, but are not limited to, vinyl chloride, epoxy, polyethylene, polypropylene, phenol, polystyrene, polyester, and acrylic resin, and other thermoplastic and thermosetting resins. It is not something to be done.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The pentahydrate borax according to the invention may be commercially available borax, but in order to obtain high-purity zinc borate, an industrial borax containing impurities is reacted with sulfuric acid at a high temperature, Cool gradually to recrystallize the boric acid crystals. The purity can be increased by changing the aging time of the zinc oxide reaction.

[0011]

The present invention will be described in more detail with reference to the following examples. In the elution impurity test, it is difficult to confirm whether or not the impurities in the zinc borate are eluted from the resin. A method of analyzing and measuring by an absorption spectrophotometer and an ion chromatograph was adopted.

Regarding the characteristics of the resin, see JIS K-572.
3 Polyvinyl chloride compound, volume resistivity test method,
The flammability standards are JIS K-7201 oxygen index measurement method, US UL-94 standard (Underw, riters, Labor
atoriesinc) etc.

The volume resistivity tester is a High Resistance Meter manufactured by Yokogawa Hillet Packard Co., Ltd. The oxygen index is ON-1 type manufactured by Suga Test Machine Co., Ltd. The evaluation was performed using a V type manufactured by Kiki Co., Ltd. The measuring device for the differential thermal analysis data is SS, manufactured by Seiko Electronics Co., Ltd.
Performed using C-5200. Alumina is used as a sample reference, and the sample is heated in air at a flow rate of 300 ml / min at a heating rate of 20 ° C./min. Here, the platinum container used in this measurement is a container having a diameter of 3 mmφ and a height of 2.5 mm, and the sample is put in the container in a powder state. The sample volume should not exceed 80% of the height of the platinum container. The data sampling interval was 0.5 seconds. An X-ray diffraction data measuring device is a Geiger manufactured by Rigaku Corporation.
A flex X-ray diffractometer was used. As measurement conditions,
Using a Kα ray of a copper target generated at a tube voltage of 30 KV and a tube current of 10 mA, a range of 2θ = 20 to 50 degrees was scanned at a rate of 1 degree per minute. 2θ- from the strongest line d to identify zinc borate _{2ZnO · 3B 2 O 3 · 3.5H} 2 O of Formula.

[0014]

Example 1 640 ml of 98% sulfuric acid in 3,930 ml of water
Was added little by little while stirring to prepare a dilute sulfuric acid solution. The temperature was 90 ° C., and pentahydrate borax 3,
330 g was charged in about 2 hours, and the mixture was stirred for 2 hours while maintaining the temperature at 90 ° C., and cooled to 35 ° C. in 4 hours to separate boric acid crystals from the mother liquor. The boric acid crystals weighed 2,390 g, and very fine crystals were obtained. This boric acid crystal 2,390
g was dissolved in 3,830 ml of water at a temperature of 90 ° C. to prepare a boric acid solution. Separately, 1,470 ml of water is prepared, 890 g of zinc oxide is added, and the mixture is stirred and dispersed for about 2 hours to prepare a slurry solution. This zinc oxide slurry solution is added to the previously prepared boric acid solution with slow stirring for 2 hours, and aged for 4 hours while maintaining the temperature at 90 ° C. to complete the reaction. This was filtered, washed with water and dried at 120 ° C. for 6 hours to obtain 2,090 g of zinc borate.

The crystalline form of the zinc borate was identified as _{2ZnO · 3B 2 O 3 · 3.5H} 2 O by X-ray diffraction析像. Since the amount of impurities is small in Na ₂ SO _{4 in the} mother liquor, it is not contained in the zinc borate crystal and Na ⁺ is 0.01%.
%, _SO ^{4 -} was 0.02%. Dissolution test results Na ⁺ is ^{20 mg} / l, _SO ^{4 -} was ^{40 mg} / l.

[0016]

Example 2 As in Example 1, 98 parts were added to 3,930 ml of water.
640 ml of sulfuric acid was added little by little while stirring to prepare a diluted sulfuric acid solution. The temperature was 90 ° C and 5
3,330 g of salt water borax is charged in about 2 hours, and further 90 ° C.
The mixture was stirred for 2 hours while keeping the temperature at 35 ° C., cooled to 35 ° C. in 8 hours, and the boric acid crystals were separated from the mother liquor. 2,4 boric acid crystals
With a weight of 00 g, a crystal larger than that of Example 1 was obtained.

2,400 g of the boric acid crystals are heated at a temperature of 90 ° C.
3. Dissolve in 830 ml of water to prepare a boric acid solution. Separately, 1,470 ml of water is prepared, 890 g of zinc oxide is added, and the mixture is stirred and dispersed for about 2 hours to prepare a slurry solution. This zinc oxide slurry solution was added to the previously prepared boric acid solution with slow stirring for 2 hours, and the temperature was adjusted to 90.
The reaction is completed by aging for 8 hours while maintaining at ℃. Thereafter, the same operation as in Example 1 was carried out to obtain a product of 2,090 g of zinc borate. The impurity content is 0.007% for Na ⁺ , SO ₄
^- was 0.014%. The dissolution test result shows that Na is 1
0 ^mg / l, _SO ^{4 -} was ^{25 mg} / l.

[0018]

Example 3 As in Example 1, 98 parts of water were added to 3,930 ml of water.
640 ml of sulfuric acid was added little by little while stirring to prepare a diluted sulfuric acid solution. The temperature was 90 ° C., and 3,330 g of pentahydrate borax was charged into this solution in about 2 hours.
Stirring was continued for 2 hours while maintaining the temperature at 35 ° C, and the temperature was slowly cooled to 35 ° C over 12 hours to separate boric acid crystals from the mother liquor. The boric acid crystal weighed 2,380 g, and the crystal was larger than that of Example 2.

2,380 g of the boric acid crystals were heated at a temperature of 90 ° C.
Dissolve in 3,830 ml of water to prepare a boric acid solution. Separately, 1,470 ml of water is prepared, 890 g of zinc oxide is added, and the mixture is stirred and dispersed for about 2 hours to prepare a slurry solution. This zinc oxide slurry solution was added to the previously prepared boric acid solution over 2 hours with slow stirring, and the temperature was increased to 90 ° C.
The reaction is completed by aging for 16 hours while maintaining at ℃. Thereafter, the same operation as in Example 1 was carried out to obtain 2,090 g of zinc borate. The impurity content is 0.003% for Na ⁺ , SO ₄
^- was 0.007%. Dissolution test results Na ⁺ is ^{3 mg} / l, _SO ^{4 -} was ^{10 mg} / l.

Example 4 2,390 g of commercially available boric acid crystals were heated at 90.degree.
Dissolve in ml of water to prepare a boric acid solution. 1,470 separately
Prepare 2 ml of water and add 890 g of zinc oxide for about 2 hours
Stir and disperse to prepare a slurry solution. This zinc oxide
Slowly add the slurry solution into the boric acid solution prepared earlier.
Add in 2 hours with stirring and keep the temperature at 90 ° C
Aging for 16 hours to complete the reaction. Hereinafter, the same as the first embodiment
This was performed in one operation to obtain a product of 2,090 g of zinc borate. Impure
Substance content is Na⁺Is 0.005%, SO₄ ⁻⁻Is 0.0
1%. The dissolution test result is also Na⁺Is 5^mg/ l, S
O ₄ ⁻⁻Is 15^mg/ l.

COMPARATIVE EXAMPLE 1 640 ml of 98% sulfuric acid was added little by little to 3,930 ml of water while stirring to prepare a dilute sulfuric acid solution.
C., and 3,330 g of pentahydrate borax was added to this solution in about 2 hours, and the temperature was further raised to 90 ° C. in 1 hour to prepare a boric acid solution. Separately, 1,760 ml of water is prepared, 1,060 g of zinc oxide is added, and the mixture is stirred and dispersed for about 2 hours to prepare a slurry solution. This zinc oxide slurry solution is
The solution is added to the boric acid solution prepared as above in 2 hours with slow stirring, and aged for 6 hours while maintaining the temperature at 90 ° C. to complete the reaction.

This was filtered, washed with water and dried at 120 ° C. for 6 hours to obtain 2.500 g of zinc borate. The crystal form of the zinc borate was determined to be 2ZnO.3B ₂ O _3.
3.5H ₂ O, and the impurity content was Na ₂ S in the mother liquor.
O ₄ is included in the zinc borate crystal during the reaction between boric acid and zinc oxide, and remains in the crystal even after washing with water. Impurity content is Na ⁺ is 0.1% _SO ^{4 -} was 0.2%. The dissolution test result also showed that Na ⁺ was 70 ^mg /
1 and SO ₄ ⁻⁻ were 150 ^mg / l.

Hereinafter, the present invention will be specifically described by way of examples using vinyl chloride resin.

Test Example 100 parts of PVC resin (103EP manufactured by Shin Daiichi PVC Co., Ltd.)
50 parts of plasticizer (manufactured by DOP God-Solvent Co., Ltd.), 30 parts of calcium carbonate (manufactured by Sankyo Seimitsu Co., Ltd.), stabilizer (manufactured by Sakai Chemical Industry Co., Ltd., tribasic lead sulfate TL-4000) 4)
(Lead stearate SL-1000) 0.5 part. Melting and kneading 15 parts of zinc borate with a biaxial electric roll at 150 ° C. for 10 minutes, and press molding with an electric heat press at 160 ° C. for 10 minutes,
A test piece having a thickness of 1 m / m for the electrical insulation and a thickness of 2 m / m for the flame retardancy test was prepared and evaluated. Table 1 shows the results.

[Table 1]In addition, according to the differential thermal analysis of Example 1 and Comparative Example 1 described above.
The analysis results are shown in FIGS. FIG. 3 (Example 1)
4 and FIG. 4 (Comparative Example 1) show the results of differential thermal analysis of zinc borate.
Also Na⁺Difference in pyrolysis temperature due to difference in content
I understand that Na of Example 1 ⁺Low zinc borate
752 ° C., whereas the Na of Comparative Example 1⁺Boric acid
Zinc is at 680 ° C. About 70 ℃ lower the decomposition temperature
I understand that Also, in resin, Na⁺Ions elute
If mixed, the decomposition temperature and ignition temperature of the resin
It is thought that the flame retardant effect is reduced due to the shift.

[0025]

As is apparent from the above results, by blending high-purity zinc borate as a flame retardant into a resin,
Excellent flame retardant effect can be obtained.

[Brief description of the drawings]

FIG. 1 is an X-ray diffraction pattern of zinc borate.

FIG. 2 is an X-ray diffraction pattern of Comparative Example 1 zinc borate.

FIG. 3 shows differential thermal data of zinc borate of Example 1.

FIG. 4 shows differential thermal data of zinc borate of Comparative Example 1.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J002 AA001 BB031 BB121 BC031 BD041 BG001 CC031 CD001 CF001 DK006 FD136 GL00 GM00 GN00 GQ00

Claims (2)

[Claims] 1. A resin composition comprising a high-purity zinc borate containing 0.01% or less of Na ^{+ and} 0.02% or less of SO ₄ ⁻⁻ as a resin flame retardant. 2. A flame-retardant resin composition comprising the zinc borate according to claim 1 and 5 to 30 parts by weight per 100 parts by weight of the resin.