CN116102868A - Application of isophthalic acid compound in flame retardant polycarbonate, a kind of flame retardant polycarbonate and its preparation method - Google Patents

Abstract

The invention belongs to the technical field of flame retardancy, and in particular relates to the application of isophthalic acid compounds in flame-retardant polycarbonate, a flame-retardant polycarbonate and a preparation method thereof. The mesobenzenedisulfonic acid compound of the present invention is used as a Lewis acid catalyst to accelerate the Fries rearrangement reaction of polycarbonate, quickly charcoal, thereby extinguishing the flame, and can achieve an excellent flame retardant effect with a very small amount of addition, at 1.1 UL‑94V0 rating in vertical burning test at mm thickness. Moreover, the isophthalic acid compound has less impact on the degradation of polycarbonate as a flame retardant due to less addition, so that the flame-retardant polycarbonate obtained by the present invention still has good mechanical properties, and the isophthalic acid Acid compounds do not contain halogen, have low smoke and low toxicity, and are environmentally friendly flame retardants, which are of great significance for practical applications.

Description

Application of isophthalic acid compounds in flame-retardant polycarbonate, flame-retardant polycarbonate and preparation method thereof

Technical Field

The invention belongs to the technical field of flame retardancy, and in particular relates to application of isophthalic disulfonic acid compounds in flame retardant polycarbonate, a flame retardant polycarbonate and a preparation method thereof.

Background Art

Polycarbonate (PC) is one of the fastest growing engineering plastics in recent years. Due to its excellent comprehensive performance, it is widely used in various fields. In order to meet the flame retardant performance requirements of PC, commonly used flame retardants mainly include bromine, sulfonate, silicon and organophosphorus. Among them, sulfonate flame retardants have the advantages of high efficiency and non-toxicity. When added to PC alone, it has achieved the UL-94V0 grade of 3mm test thickness. However, in recent years, with the development of the electronic and electrical industry, the application development of PC has developed in the direction of lightweight, so higher requirements are put forward for the flame retardant performance of thin-walled PC (thickness less than 2mm).

At present, the existing technology uses industrially produced sulfonate flame retardants, such as potassium perfluorobutyl sulfonate and potassium diphenyl sulfone sulfonate, in combination with bromine or silicon flame retardants, which can usually only achieve a UL-94V0 grade of 1.6mm test thickness. At the same time, since the composite material contains halogens, it has an adverse impact on the environment. Most importantly, the existing sulfonate flame retardants cause PC degradation, resulting in a decrease in its mechanical properties.

Summary of the invention

In view of this, the purpose of the present invention is to provide an application of isophthalic acid compounds in flame-retardant polycarbonate, a flame-retardant polycarbonate and a preparation method thereof. The present invention applies isophthalic acid compounds as flame retardants to flame-retardant polycarbonate, and the obtained flame-retardant polycarbonate has good flame retardant properties and mechanical properties, is halogen-free, and is green and environmentally friendly.

In order to achieve the above object, the present invention provides the following technical solutions:

The invention provides application of isophthalic acid compounds in flame retardant polycarbonate. The isophthalic acid compounds include isophthalic acid and/or isophthalic acid salts.

Preferably, the molecular formula of the isophthalate is C ₆ H ₄ (SO ₃ X) ₂ , and the structural formula of the isophthalate is as shown in Formula I:

In the formula I, X is one or more of K, Li and Na.

The present invention also provides a flame retardant polycarbonate, wherein the raw materials for preparing the flame retardant polycarbonate include the following components in terms of mass percentage:

The isophthalic acid compound is the isophthalic acid compound used in the above application.

Preferably, the anti-drip agent comprises polytetrafluoroethylene and/or polyvinylidene fluoride.

Preferably, the antioxidant comprises pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and/or tris(2,4-di-tert-butylphenyl)phosphite.

Preferably, the polycarbonate is bisphenol A polycarbonate.

The present invention also provides a method for preparing the flame retardant polycarbonate described in the above technical solution, comprising the following steps:

The polycarbonate, isophthalic acid compounds, an anti-dripping agent and an antioxidant are mixed, and melt-kneaded, extruded, pelletized and dried in sequence to obtain a flame-retardant polycarbonate.

Preferably, before mixing the polycarbonate, the isophthalic acid compound, the anti-dripping agent and the antioxidant, the method further comprises: dehydrating the polycarbonate and the isophthalic acid compound; the dehydration temperature is 80 to 120° C., and the dehydration time is 4 to 12 hours.

Preferably, the temperature of the melt-kneading is 230-300° C.; and the time of the melt-kneading is 20-60 min.

Preferably, the extrusion temperature is 240-270° C.; and the extrusion time is 20-30 min.

The present invention provides an application of isophthalic acid compounds in flame-retardant polycarbonate. The isophthalic acid compounds of the present invention act as Lewis acid catalysts to accelerate the Fries rearrangement reaction of polycarbonate, quickly form carbon, and thus extinguish the flame, and can achieve an excellent flame retardant effect when added in a very small amount, reaching the UL-94V0 grade in a vertical combustion test at a thickness of 1.1 mm. Moreover, the isophthalic acid compounds act as flame retardants, and the effect of polycarbonate degradation caused by a small amount of addition is small, so that the flame-retardant polycarbonate obtained by the present invention still has good mechanical properties, and the isophthalic acid compounds do not contain halogens, have low smoke and low toxicity, and are environmentally friendly flame retardants, which are of great significance for practical applications.

DETAILED DESCRIPTION

The invention provides application of isophthalic acid compounds in flame retardant polycarbonate.

In the present invention, the isophenylenedisulfonic acid compound includes isophenylenedisulfonic acid and/or isophenylenedisulfonate, preferably isophenylenedisulfonate.

In the present invention, the molecular formula of the isophthalate is C ₆ H ₄ (SO ₃ X) ₂ , and the structural formula of the isophthalate is shown in Formula I:

In the formula I, X is preferably one or more of K, Li and Na, and more preferably K. When X is multiple, the present invention has no special limitation on the ratio of different types of X, and any ratio is acceptable.

The present invention also provides a flame retardant polycarbonate, wherein the raw materials for preparing the flame retardant polycarbonate include the following components in terms of mass percentage:

The isophthalic acid compound is the isophthalic acid compound used in the above application.

Unless otherwise specified, the present invention has no special requirements on the sources of the raw materials used in the preparation, and commercially available products known to those skilled in the art can be used.

The raw material for preparing the flame retardant polycarbonate provided by the present invention comprises polycarbonate with a mass percentage of 98-99.849%, preferably 99-99.19%.

In the present invention, the polycarbonate is bisphenol A polycarbonate.

The raw materials for preparing the flame retardant polycarbonate provided by the present invention include 0.001-0.5% by mass of isophenyl disulfonic acid compounds, preferably 0.01-0.1% by mass.

The intermediate benzene disulfonic acid compound of the present invention acts as a Lewis acid catalyst to accelerate the Fries rearrangement reaction of polycarbonate, quickly forms carbon, and thus extinguishes the flame. It can achieve an excellent flame retardant effect with a very small addition amount, reaches the UL-94V0 grade in a vertical burning test at a thickness of 1.1 mm, and does not contain halogen, and is an environmentally friendly flame retardant.

The raw materials for preparing the flame retardant polycarbonate provided by the present invention include an anti-dripping agent in an amount of 0.05-0.5% by weight, preferably 0.1-0.3% by weight.

In the present invention, the anti-drip agent preferably includes polytetrafluoroethylene and/or polyvinylidene fluoride, and more preferably polytetrafluoroethylene. When there are multiple types of anti-drip agents, the present invention has no special restrictions on the ratio of different types of anti-drip agents, and any ratio is acceptable.

The anti-dripping agent added in the present invention can improve the melting dripping phenomenon during the combustion process and avoid the grade reduction in the UL94 test.

The raw materials for preparing the flame retardant polycarbonate provided by the present invention include an antioxidant in an amount of 0.1 to 1.0% by mass, preferably 0.2 to 0.6% by mass.

In the present invention, the antioxidant preferably includes pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and/or tris(2,4-di-tert-butylphenyl)phosphite, and more preferably pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl)phosphite. When the antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl)phosphite, the present invention has no particular limitation on the ratio of the two antioxidants, and any ratio is acceptable.

The antioxidant added in the present invention can prevent the thermal oxidation degradation of the substrate.

The present invention also provides a method for preparing the flame retardant polycarbonate described in the above technical solution, comprising the following steps:

The polycarbonate, isophthalic acid compounds, an anti-dripping agent and an antioxidant are mixed, and melt-kneaded, extruded, pelletized and dried in sequence to obtain a flame-retardant polycarbonate.

The invention mixes polycarbonate, isophthalic acid compounds, an anti-dripping agent and an antioxidant to obtain a mixture.

Before mixing the polycarbonate, isophthalic acid compounds, anti-dripping agent and antioxidant, the present invention preferably further comprises: dehydrating the polycarbonate and isophthalic acid compounds; the dehydration temperature is preferably 80 to 120° C., more preferably 90 to 120° C.; the dehydration time is preferably 4 to 12 hours, more preferably 5 to 8 hours.

The ester group in polycarbonate is easily hydrolyzed, and the role of dehydration is to prevent the hydrolysis of polycarbonate.

The present invention has no special limitation on the mixing process, and the materials can be mixed evenly using a mixing method well known in the art.

After obtaining the mixed material, the present invention melt-kneads the mixed material.

In the present invention, the melt-kneading temperature is preferably 230 to 300° C., more preferably 240 to 260° C.; the melt-kneading time is preferably 20 to 60 min, more preferably 30 to 45 min.

After the melt-kneading, the present invention extrude the molten mixture obtained by the melt-kneading.

In the present invention, the extrusion temperature is preferably 240 to 270° C.; the extrusion time is preferably 20 to 30 min.

In the present invention, the extrusion equipment is preferably a twin-screw extruder; the extrusion procedure of the twin-screw extruder is preferably: zone one: temperature is 240-255°C; zone two: temperature is 245-265°C; zone three: temperature is 255-270°C; zone four: temperature is 255-270°C; zone five: temperature is 250-265°C; head: temperature is 245-260°C.

After the extrusion, the present invention preferably cools the extruded material to room temperature to obtain a cooled material; the cooling is preferably performed by water cooling followed by drying; the equipment used for drying is preferably a drying machine of a twin-screw extruder.

After obtaining the cooling material, the present invention pelletizes the cooling material to obtain a granular material.

In the present invention, the device used for the pelletizing is preferably a pelletizer; the particle size of the granular composite material obtained by the pelletizing is preferably 3 to 4 mm, more preferably 3 mm.

After obtaining the granular material, the present invention dries the granular material to obtain flame retardant polycarbonate.

In the present invention, the drying temperature is preferably 120° C.; the drying time is preferably 4 hours; and the drying equipment is preferably a forced air oven.

The preparation method of the flame retardant polycarbonate provided by the invention is simple, has a short cycle and is suitable for mass production.

The technical solutions of the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention, but they should not be construed as limiting the protection scope of the present invention.

Example 1

A flame retardant polycarbonate, wherein the raw materials for its preparation include the following components in terms of mass percentage:

991.9g of polycarbonate (bisphenol A type polycarbonate) and 0.1g of dipotassium isophthalate were dehydrated at 120°C for 4h, mixed with 3g of polytetrafluoroethylene, 2g of tris(2,4-di-tert-butylphenyl)phosphite, and 3g of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, melt-kneaded at 260°C for 45min by a twin-screw extruder, and then extruded. The extrusion procedure was as follows: zone 1: temperature of 245°C; zone 2: temperature of 260°C; zone 3: temperature of 270°C; zone 4: temperature of 260°C; zone 5: temperature of 260°C; die head: temperature of 260°C, extrusion time of 20min, after cooling with water, dried with a blow dryer of the extruder, cut into particles with a particle size of 3mm with a pelletizer, and dried in a blast oven at 120°C for 4h to obtain flame-retardant polycarbonate.

Example 2

A flame retardant polycarbonate, wherein the raw materials for its preparation include the following components in terms of mass percentage:

991.9 g of polycarbonate and 0.1 g of disodium isophenyl disulfonate were dehydrated at 120° C. for 4 h, and then mixed with 2 g of poly(tetrafluoroethylene-hexafluoroethylene), 3 g of tris(2,4-di-tert-butylphenyl) phosphite, and 3 g of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, melt-kneaded at 245° C. for 45 min by a twin-screw extruder, and then extruded. The extrusion procedure was as follows: zone 1: temperature of 245° C.; zone 2: temperature of 260° C.; zone 3: temperature of 270° C.; zone 4: temperature of 270° C.; zone 5: temperature of 260° C.; die head: temperature of 260° C., extrusion time of 20 min, after cooling with water, dried with a blow dryer of the extruder, cut into particles with a particle size of 3 mm with a pelletizer, and dried in a blast oven at 120° C. for 4 h to obtain flame-retardant polycarbonate.

Example 3

A flame retardant polycarbonate composition, wherein the raw materials for its preparation include the following components in terms of mass percentage:

991.5g of polycarbonate and 0.5g of dipotassium isophthalate were dehydrated at 120°C for 4h, mixed with 3g of polytetrafluoroethylene, 2g of tris(2,4-di-tert-butylphenyl)phosphite and 3g of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, melt-mixed at 245°C for 45min by a twin-screw extruder, and then extruded. The extrusion procedure was as follows: zone 1: temperature of 250°C; zone 2: temperature of 265°C; zone 3: temperature of 270°C; zone 4: temperature of 270°C; zone 5: temperature of 265°C; die head: temperature of 245°C, extrusion time of 20min, after cooling with water, dried with a blow dryer of the extruder, cut into particles with a particle size of 3mm with a pelletizer, and dried in a blast oven at 120°C for 4h to obtain flame-retardant polycarbonate.

Example 4

A flame retardant polycarbonate composition, wherein the raw materials for its preparation include the following components in terms of mass percentage:

991.5g of polycarbonate and 0.5g of disodium isophenyl disulfonate were dehydrated at 120°C for 4h, mixed with 3g of polytetrafluoroethylene, 2g of tris(2,4-di-tert-butylphenyl)phosphite and 3g of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, melt-mixed at 250°C for 45min by a twin-screw extruder, and then extruded. The extrusion procedure was as follows: zone 1: temperature of 255°C; zone 2: temperature of 260°C; zone 3: temperature of 270°C; zone 4: temperature of 270°C; zone 5: temperature of 260°C; die head: temperature of 255°C, extrusion time of 20min, after cooling with water, dried with a blow dryer of the extruder, cut into particles with a particle size of 3mm with a pelletizer, and dried in a blast oven at 120°C for 4h to obtain flame-retardant polycarbonate.

Comparative Example 1

A flame retardant polycarbonate composition, wherein the raw materials for its preparation include the following components in terms of mass percentage:

984.5g of polycarbonate and 7.5g of dipotassium isophthalate were dehydrated at 120°C for 4h, mixed with 3g of polytetrafluoroethylene, 2g of tris(2,4-di-tert-butylphenyl)phosphite and 3g of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, melt-mixed at 250°C for 45min by a twin-screw extruder, and then extruded. The extrusion procedure was as follows: zone 1: temperature of 255°C; zone 2: temperature of 260°C; zone 3: temperature of 270°C; zone 4: temperature of 270°C; zone 5: temperature of 260°C; die head: temperature of 255°C, extrusion time of 20min, after cooling with water, dried with a blow dryer of the extruder, cut into particles with a particle size of 3mm with a pelletizer, and dried in a blast oven at 120°C for 4h to obtain flame-retardant polycarbonate.

Performance Testing

The polycarbonate, the flame-retardant polycarbonate obtained in Examples 1 to 4 and Comparative Example 1 were prepared into test specimens by injection molding according to standard size requirements.

LOI: According to the requirements of GB/T 2406.2-2009, the limiting oxygen index (LOI) of the polycarbonate, the flame retardant polycarbonate obtained in Examples 1 to 4 and Comparative Example 1 was measured using a TTech-GBT2406-1 limited oxygen index tester. The sample size was 100 mm×6.5 mm×3 mm.

UL 94 grade test: The polycarbonate, the flame retardant polycarbonate obtained in Examples 1 to 4 and Comparative Example 1 were tested vertically using a UL94-X horizontal vertical combustion tester on samples with a size of 125 mm × 13 mm × 1.6 mm and 125 mm × 13 mm × 1.1 mm. The test adopted the UL-94 standard. In this test, according to ANST/UL-94-2021, the combustion grade of the material is divided into V-0, V-1, V-2 or NR (no grade).

Mechanical tensile test: The tensile test of the polycarbonate, the flame retardant polycarbonate obtained in Examples 1 to 4 and Comparative Example 1 was carried out on a DXLL-5000 electronic universal mechanical testing machine at a tensile rate of 20 mm/min. The reported data is the average result of at least five samples.

The performance test results of the polycarbonate, the flame retardant polycarbonate obtained in Examples 1 to 4 and Comparative Example 1 are shown in Table 1.

Table 1 Performance test results of polycarbonate, flame retardant polycarbonate obtained in Examples 1 to 4 and Comparative Example 1

As can be seen from Table 1, the flame retardant polycarbonate composition containing isophthalic acid compounds prepared by the present invention has a higher oxygen index than polycarbonate, and in the vertical burning test at a thickness of 1.1 mm, Examples 1 and 2 reach the UL-94V0 grade, and the flame retardant polycarbonate composition containing isophthalic acid compounds of the present application still has good mechanical properties.

Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention rather than all the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims (10)

1. Application of isophthalic acid compounds in flame-retardant polycarbonate, characterized in that the isophthalic acid compounds include isophthalic acid and/or isophthalic acid salts. 2. The use according to claim 1, characterized in that the molecular formula of the isophenyl disulfonate is C ₆ H ₄ (SO ₃ X) ₂ , and the structural formula of the isophenyl disulfonate is as shown in Formula I:

In the formula I, X is one or more of K, Li and Na. 3. A flame retardant polycarbonate, characterized in that, in terms of mass percentage, its raw materials for preparation include the following components:

The isophthalic acid compound is the isophthalic acid compound used in any one of claims 1 to 2. 4 . The flame retardant polycarbonate according to claim 3 , wherein the anti-dripping agent comprises polytetrafluoroethylene and/or polyvinylidene fluoride. 5. The flame-retardant polycarbonate according to claim 3, characterized in that the antioxidant comprises pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and/or tris(2,4-di-tert-butylphenyl)phosphite. 6 . The flame retardant polycarbonate according to claim 3 , wherein the polycarbonate is bisphenol A polycarbonate. 7. The method for preparing the flame retardant polycarbonate according to any one of claims 3 to 6, comprising the following steps: The polycarbonate, isophthalic acid compounds, an anti-dripping agent and an antioxidant are mixed, and melt-kneaded, extruded, pelletized and dried in sequence to obtain a flame-retardant polycarbonate. 8. The preparation method according to claim 7 is characterized in that before mixing the polycarbonate, the isophthalic acid compound, the anti-dripping agent and the antioxidant, it also includes: dehydrating the polycarbonate and the isophthalic acid compound; the dehydration temperature is 80 to 120° C., and the dehydration time is 4 to 12 hours. 9 . The preparation method according to claim 7 , characterized in that the temperature of the melt-kneading is 230 to 300° C. and the time of the melt-kneading is 20 to 60 minutes. 10 . The preparation method according to claim 7 , characterized in that the extrusion temperature is 240 to 270° C. and the extrusion time is 20 to 30 min.