KR940006463B1 - Flame retardant styrenic resin composition - Google Patents

Abstract

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Description

Flame retardant styrene resin composition with excellent heat resistance and light resistance

The present invention relates to a flame retardant and styrene resin composition excellent in heat resistance and light resistance.

As a thermal stabilizer when conventionally flame retarding a styrene resin with hexabromocyclododecane (hereinafter also referred to as "HBCD"), for example, organic tin-based polymers such as those described in Japanese Unexamined Patent Publication No. 59-43060; It is known to mix an organotin compound, an organophosphorus compound, and an epoxy compound as described in isopropylidenediphenyl group-containing organophosphorus compound or JP 62-34784A.

However, in the known flame retardant method of styrene resin by HBCD, 1) the heat resistance and light resistance of HBCD itself are poor, and because of this, the heat stabilized molding resin can not be used for moldings for pale color use. Thermal decomposition of HBCD itself occurs and not only the mold corrodes due to the generated hydrogen bromide, but also the physical properties, light resistance and flame retardancy of the resin decrease. ③ Since the content ratio of isomers in HBCD is not constant, There is a problem of poor quality or reliability, ④ It is difficult for the molding process maker to use because of precise control of the molding temperature, and ⑤ It is difficult to reuse the molding waste.

In view of the above settings, the present invention aims to provide a flame retardant styrene resin composition in which the above problems in the prior art are used by using a specific high melting point HBCD isomer and a heat stabilizer in combination.

MEANS TO SOLVE THE PROBLEM As a result of dealing with the inherent substance of HBCD used until now as a flame retardant of a styrene resin, the existing HBCD contains the high melting point isomer of 206 degreeC and the low melting point isomer of 159 degreeC. The high-melting isomer is suitable for flame retardation of the styrene counter, but the low-melting point is decomposed at the working temperature at the time of molding to confirm that it is inappropriate for the purpose. Furthermore, it was confirmed that the undesirable properties exhibited by commercially available HBCD products are due to the mixing of low-melting HBCD isomers other than the high-melting isomers with low-bromine compounds of less than 5 bromide.

This invention is based on the above knowledge, The summary is the flame-retardant styrene excellent in heat resistance and light resistance characterized by consisting of a styrene resin, the high melting point isomer containing content 80% or more of hexabromocyclododecane, and a heat stabilizer. It is in the counting composition.

Hereinafter, the main points regarding the structure of the invention will be described item by item.

The styrene resin which comprises this invention is generally called a styrene resin, such as the polymer (alpha)-ethylstyrene styrene monomer copolymer of a styrene monomer.

Moreover, this resin may also contain the 3rd component, such as a small amount of butadiene, methyl methacrylate, acrylonitrile, styrene bromide, maleic anhydride, and itaconic acid.

The HBCD constituting the composition of the present invention is at least 80% by weight of the high melting point isomer having a melting point of 206 캜. It is preferable that the low-melting isomer of melting point 159 DEG C is less than 20% by weight, even if it is not included or is included, and the amount of the lower bromine is not more than 0.5% by weight, especially 0.1% by weight or less.

Such HBCD is obtained by purifying a commercially available HBCD with a polar solvent of dissolution parameter (SP) 8-12 alone or a mixed solvent with C ₁ -C ₅ alcohol.

To constantly adjust the mixing ratio of the high melting point isomer and the low melting point isomer of HBCD, the high melting point isomer is changed into a high purity low melting point isomer by heating and thermally displaced in an organic solvent under the introduction of nitrogen gas. It is good to mix the melting point isomers properly. It is also possible to heat the high melting point isomer under a solvent to a temperature above its melting point and thermally dissolve it, but it is difficult to obtain a high purity low melting point isomer due to thermal decomposition.

Even in the case of a single high melting point isomer having relatively high heat resistance, when heated to a temperature above the melting point, it is colored and generates hydrogen bromide gas to change to a low bromide of 5 or less bromide.

Moreover, the HBCD obtained based on the known synthesis technique is a reaction of ttc-cyclododecatene and bromine in an organic solvent, but the ratio of the high melting point HBCD isomer and the low melting point HBCD isomer in the reaction system is approximately 65/35. The ratio is almost constant. The production of impurities of 5 bromide or less is approximately 15 to 20% by weight depending on the reaction conditions.

Compounds below the pentabromide of the reaction product, when added to the styrene resin, significantly lower the heat resistance and light resistance, but the low-melting isomers are inferior in heat resistance to the high-melting isomers, but have excellent compatibility with the resin. It acts to stabilize the physical properties of the resin.

In the composition of the present invention, as the pentaerythritol-type diphosphite compound in the heat stabilizer, for example, distearyl pentaerythritol diphosphite, bis (2,4-di-t-butylphenyl) -pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-methylphenyl) -pentaerythritol diphosphite, dinonylphenyl pentaerythritol diphosphite, etc. are mentioned.

Examples of the organic tin-containing sulfur compound include dibutyltin-3-mercaptopropionate, di-n-octyltin-3-mercaptopropionate, dibutyltin mercaptoacetic acid salt and diethylene glycol bis (butyltin). Thioacetate), dibutyltin sulfide, dioctyl tin silphide, dibutyltin dioctyl mercaptide, dimethyltin bis (ethylene glycol monothioglycolate), dibutyltin bis (ethylene glycol monothioglycolate), and the like. These may be used together or in combination with other stabilizers. However, in some cases, the stability may decrease due to the antagonism between the stabilizer and the resin composition.

Although the method of adding a heat stabilizer may be any method, the method of adding to a predetermined | prescribed HBCD of this invention, and mix | blending with resin is preferable.

Usually, it is good to add the said HBCD in the ratio of 0.5-10 weight part with respect to 100 weight part of styrene resins, and it is sufficient that a heat stabilizer is added 0.2-10 weight part with respect to 100 weight part of the HBCD.

The molding processing temperature is suitably in the range of 200 to 235 ° C. If it is less than 200 degreeC, the fluidity | liquidity of resin falls, and when it becomes 240 degreeC or more, there exists a possibility that coloring and decomposition may arise.

The present invention makes it possible to realize a flame retardant styrene resin composition having excellent heat resistance and light resistance by using HBCD containing 80 wt% or more of high melting point isomer as a component imparting flame retardancy.

EXAMPLE

Although the embodiments and effects of the present invention have been described with reference to the following examples, the examples are for illustrative purposes only and are not intended to limit or limit the scope of the invention.

In addition, "part" and "%" represent a basis of weight in an Example.

Example 1 (Preparation of HBCD Sample)

(a) Synthesis of HBCD

420 parts of isoamyl alcohol and 4.2 parts of BF ₃ -ethyl ether complex salt were placed in a flask, and 495 parts (3.09 mol) of bromine and 162 parts (1 mol) of 1,5,9-cyclododecatene were added at a reaction temperature of 20 to 30 ° C. It was dripped at the same time, and after completion | finish of dripping, stirring was continued for 2 hours. The composition of crude HBCD produced in the reaction system was 57.8% of high melting point HBCD, 26.2% of low melting point HBCD, and 16.0% of 5 bromide or less.

The reaction system was then cooled to 20 ° C., and 20% sodium methylatemethanol solution was added to neutralize to pH 8-8.5. The resulting crystals were collected by filtration and washed with methanol to obtain 559 parts of ordinary HBCD (isomer mixture).

Next, 200 parts of ordinary HBCD was added to the mixed solvent of 160 parts of methyl isobutyl ketones (S.P 8.4) and 140 parts of methanol, and it stirred and dissolved at 70 degreeC for 1 hour.

The solution was cooled to 25 ° C, the resulting crystals were collected by filtration, washed with 100 parts of methanol and dried to obtain 65 parts of high purity high melting point HBCD.

100 parts of the obtained high-purity high melting point isomers were heated in 200 parts of xylenes while introducing nitrogen gas, heated up while distilling off the xylenes, and held at 190 ° C for 40 minutes, and then cooled. Thereafter, the solvent was removed by vacuum drying to obtain high-purity low melting point HBCD.

The obtained high purity high melting point isomer and high purity low melting point isomer were mix | blended suitably, and the specific HBCD of Table-1 below was adjusted.

Table-1

Analysis of isomers and the like is carried out by reverse phase liquid chromatography. The measurement of MP (melting point) is by Rigaku TAS DCS 8230.

In Table-1, D is a mixture of high purity high melting point isomers and high purity low melting point isomers in a ratio of 93: 7. E is a mixture of high purity high melting point isomers and high purity low melting point isomers at a ratio of 84/16.

Example 2 (Thermal Stability of HBCD Samples)

The heat coloring property and volatilization loss at the time of adding the weight loss start temperature and 210 degreeC x 20 minutes of heat historys with or without adding various heat stabilizers to the samples A-E of Table-1 were measured. The results are shown in Table-2 below.

TABLE 2

1) By differential thermal analysis. 2) 2w / v% acetone solution

Thermal Stabilizer:

(A): bis (2,6-di-t-butyl-4-methylphenyl) -pentaerythritol diphosphite

(B) bis (2,4-di-t-butylphenyl) -pentaerythritol diphosphite

(C) Dibutyltin-3-mercaptopropyrinate

(ㄹ): Dibutyltin sulfide

(ㅁ): Di-n-octyl tin maleate polymer

(Iii): Diglycidyl ether of 2, 2-bis (4-oxyphenyl propane)

Example 3 (Example 1)

HBCD of Table-2 Invention Examples 1 and 3 and Comparative Examples 1 and 3 were added to HI polystyrene resin (manufactured by Shinnitetsu Chemical Co., Ltd.) (<< Estyrene H45 >> Co., Ltd.). It knead | mixed at 3 degreeC for 3 minutes. After pressing the obtained compound | combination at 200 degreeC and 20 atmospheres for 3 minutes, it put on the cooling screw press and obtained the test sheet. The results of the measurement of color change, flame retardancy and physical properties using this sheet are shown in Table-3 below.

Table-3

3): The obtained plastic sheet was heated in an oven at 210 ° C. for 60 minutes, and the color tone was measured by a colorimeter.

4): It carried out according to JISK-7201 (Oxygen concentration index).

5,6): It carried out according to JISK-6871.

7) The obtained plastic sheet was irradiated with a weather resistance tester (63 ° C.) for 24 hours, and the color tone was measured by a colorimeter.

Example 4 (Example 2)

Table 2 Inventive Examples 1 and 3 and HBCDs of Comparative Examples 1 and 3 were added to the GP polystyrene resin (manufactured by Shinnitetsu Chemical Co., Ltd.) and stirred and mixed. After kneading with an extruder having an internal diameter of 40 m / mψ adjusted to 0 ° C., the mixture was cooled to 130 ° C., extruded and foamed under pressure of 8 kg / cm 2 from a die having a diameter of 4 m / mψ.

The obtained foam was crushed into chips, and the chips were refoamed under the same conditions by a foaming machine. Table 4 shows the results of measuring the flame retardancy, physical properties, thermal stability, particle size of the foam, and extrusion stability of the obtained foam.

Table-4

3): When evaluation occurs in case of phenomenon such as separation of resin and foaming agent, abnormal foaming, dispersion of foaming magnification, etc., which occur due to poor operation stability during extrusion molding, the symbol X is indicated. The case where it appears slightly is represented by the symbol (triangle | delta).

9): Viscosity (%) when relative viscosity (n / rel) of styrene resin (before adding flame retardant and stabilizer) is 100%

Conditions: 25 ° C.-0.5g / 100c. Toluene Solubility

Viscometer: Canon Heske

Example 4 (Example 3)

1000 parts of HI polystyrene resin (<< Estyrene H-65 >>) Shin-Nitetsu Chemical Co., Ltd.) HBCD 985.3 parts and dibutyl tin maleate polymer of Table 2 invention 3 and Comparative Example 3 14.5 parts were mixed with a vertical mixer, kneaded with an extruder having an internal diameter of 20 m / mψ adjusted to 190 ° C, cooled to 130 ° C, and extruded from a die having a diameter of 3m / mψ. The resulting strands were cut to prepare 50% master pellets. The obtained master pellet was mixed with HI polystyrene resin, and the test piece was obtained by injection molding using the injection molding machine adjusted to 210 degreeC.

For the above specimens, the results of measuring color tone change, flame retardancy, and physical properties as shown in Example 3 are shown in Table 5 below.

Table-5

10): u1-94 was carried out.

As described and demonstrated above, the present invention provides a flame-retardant styrene that provides heat-resistant and light-resistant moldings with little thermal degradation without worry of mold corrosion at general working temperatures such as injection molding, extrusion molding or rolling in styrene resins. In addition to providing a counting paper, high concentrations of HBCDs can produce a masterbatch, which contributes to the improvement of the work environment by dust.

Claims (1)

0.5 to 10 parts by weight of hexabromocyclododecane containing 80% by weight or more of a high melting point isomer containing styrene resin and 100 parts by weight of this styrene resin, and pentaeryte to 100 parts by weight of this hexabromocyclododegan. A flame retardant styrene resin composition having excellent heat resistance and light resistance, comprising 0.2 to 10 parts by weight of at least one thermal stabilizer selected from a ritol type diphosphite compound and an organotin-containing sulfur compound.