CN112592566B

CN112592566B - Low-smoke-density halogen-containing flame-retardant reinforced PBT/PET compound and preparation method and application thereof

Info

Publication number: CN112592566B
Application number: CN202011349058.9A
Authority: CN
Inventors: 陈伟; 黄险波; 叶南飚; 冯健; 陈锐; 付学俊
Original assignee: Kingfa Science and Technology Co Ltd
Current assignee: Kingfa Science and Technology Co Ltd
Priority date: 2020-11-26
Filing date: 2020-11-26
Publication date: 2022-03-22
Anticipated expiration: 2040-11-26
Also published as: CN112592566A; WO2022110663A1

Abstract

The invention discloses a low-smoke-density halogen-containing flame-retardant reinforced PBT/PET compound, and a preparation method and application thereof. The low-smoke-density halogen-containing flame-retardant reinforced PBT/PET compound comprises the following components: PBT, PET, glass fiber, brominated flame retardant, synergistic flame retardant, epoxy resin, boehmite, kaolin and magnesium stearate; the weight ratio of the PBT to the PET is (1-4) to 1, and the particle size D50 of the magnesium stearate is not more than 5 mu m. By compounding PET with PBT in a proper proportion and the synergistic effect of boehmite, kaolin and magnesium stearate with a specific particle size, the smoke density of the PBT/PET compound reaches grade 3 of the smoke density required by EN45545-2 standard, the smoke density Ds max is less than or equal to 150, and meanwhile, the PET/PET product prepared by using the PBT/PET compound has high appearance glossiness.

Description

Low-smoke-density halogen-containing flame-retardant reinforced PBT/PET compound and preparation method and application thereof

Technical Field

The invention relates to the technical field of engineering plastics, and particularly relates to a low-smoke-density halogen-containing flame-retardant reinforced PBT/PET compound, and a preparation method and application thereof.

Background

Plastic materials are generally produced with a large amount of smoke in the combustion process, and can cause environmental pollution and great harm to human bodies. In recent years, with the development of plastic flame retardant technology, low-smoke flame retardant has become a new direction for the development of flame retardant plastics. The demand of industries such as rail transit, building materials, cables and the like on the aspect of low smoke and flame retardance is more obvious and standardized, and the industries have clear requirements that plastic parts in application must reach the smoke density level 2 or above required by EN45545-2 standard (the smoke density Ds max is less than or equal to 300 required by ISO5659-2 test level 2).

Polybutylene terephthalate (PBT) is polymerized by terephthalic acid and butanediol through polycondensation reaction, and the PBT material reinforced by glass fiber is widely applied to lighting lamps, cooling fans, connectors, coil frameworks, electric appliance shells and other electronic and electrical components at present. With the development of the technology, people have higher and higher requirements on the performance of the PBT modified material, and meanwhile, the pressure of the cost also forces the change, and under the condition, the glass fiber reinforced PBT/PET alloy material with better performance is produced. Polyethylene terephthalate (PET) has good heat resistance and lower cost, and the PET can effectively prevent glass fiber from being exposed in a glass fiber reinforced PBT system, thereby having the effect of high light on the surface of the product.

When the glass fiber reinforced PBT/PET alloy is applied to the industries of rail transit, building materials, cables and the like, the flame retardance and the smoke suppression modification are indispensable, and particularly when the glass fiber reinforced PBT/PET alloy is applied to certain scenes with extremely high requirements on smoke suppression performance, the smoke density is required to reach the EN45545-2 standard grade 3 level (the smoke density Ds max of an ISO5659-2 test is less than or equal to 150). Chinese patent CN111534060A discloses a reinforced flame-retardant PBT/PET alloy which comprises PBT, PET, glass fiber, a brominated flame retardant and other components, and the prepared reinforced flame-retardant PBT/PET alloy has good heat resistance and flame retardance, but does not pay attention to smoke amount or smoke density indexes. Chinese patent application CN 102532826A discloses a low-cost flame-retardant glass fiber reinforced PBT engineering plastic, which utilizes the smoke suppression effect of silicate to prepare the low-cost flame-retardant glass fiber reinforced PBT engineering plastic with better flame retardance, but the smoke density of the low-cost flame-retardant glass fiber reinforced PBT engineering plastic cannot meet the EN45545-2 standard level 3.

Therefore, the improvement of the smoke suppression performance of the halogen-containing flame-retardant reinforced PBT/PET compound is urgently needed.

Disclosure of Invention

The invention aims to overcome the defects of fiber floating on the surface and high smoke density in the prior art, and provides the low-smoke-density halogen-containing flame-retardant reinforced PBT/PET compound which has good glossiness and flame retardance and achieves the smoke density reaching the level of EN45545-2 standard level 3.

The invention also aims to provide a preparation method of the low-smoke density halogen-containing flame-retardant reinforced PBT/PET compound.

The invention also aims to provide application of the low-smoke density halogen-containing flame-retardant reinforced PBT/PET compound.

In order to solve the technical problems, the invention adopts the technical scheme that:

a low-smoke density halogen-containing flame-retardant reinforced PBT/PET compound comprises the following components in parts by weight:

15-50 parts of polybutylene terephthalate (PBT),

8-30 parts of polyethylene terephthalate (PET),

10-40 parts of glass fiber,

10 to 16 parts of a bromine-based flame retardant,

3-7 parts of a synergistic flame retardant,

0.5 to 1 part of epoxy resin,

2-4 parts of boehmite,

2-8 parts of kaolin clay, namely,

2-4 parts of magnesium stearate;

the weight ratio of the PBT to the PET is (1-4) to 1,

particle size D of the magnesium stearate₅₀≤5μm。

The inventor finds that when PET is compounded with PBT in a proper proportion, the floating fiber can be obviously reduced, the surface gloss of the material is improved, and the smoke density level of the compound can be effectively reduced. Furthermore, under the synergistic effect of boehmite, kaolin and magnesium stearate with specific particle size, the smoke density of the halogen-containing flame-retardant reinforced PBT/PET compound can reach an extremely low level, the smoke density Ds max tested by ISO5659-2-2016 is less than or equal to 150, and the requirement of EN45545-2 standard grade 3 is met. The particle size D of the magnesium stearate in the technical scheme of the invention₅₀The particle size of magnesium stearate is required to be less than or equal to 5 mu m, and if the particle size of magnesium stearate is too large, the smoke suppression effect of the invention cannot be achieved.

The magnesium stearate is preferably a product of Shangxi Macro-Yuan chemical industry brand YZM-32C.

The molecular formula of the boehmite is gamma-AlOOH, and the average grain size of the boehmite is more than or equal to 10 nm.

Due to the characteristics of low density, larger surface area, special structure and morphology and the like, the boehmite with lower grain size has special physical and chemical properties different from those of the boehmite with large grain size, and the smoke generation amount of the material during combustion can be more remarkably reduced in a halogen-containing flame-retardant reinforced PBT/PET system. Preferably, the boehmite preferably has an average grain size of 10 to 20 nm.

The boehmite is preferably a product of Nanjing Epsilon nano-material Co., Ltd, and the model is boehmite 235.

The inventor finds that the kaolin with moderate acidity and lower particle size can play a better smoke suppression effect in a PBT/PET system.

Preferably, the particle size of the kaolin is preferably D₅₀≤0.5μm。

Preferably, the pH value of the kaolin is preferably 4-5.

The kaolin is preferably a product of the Hangzhou Chongke new materials Co., Ltd, with the mark of Eckalite 1 PLUS.

Preferably, the weight ratio of the boehmite to the kaolin to the magnesium stearate is 1: 1-2: 1.

The inventor researches and discovers that when boehmite, kaolin and magnesium stearate are compounded in a weight ratio of 1: 1 (1-2) to 1, the prepared halogen-containing flame-retardant reinforced PBT/PET compound can obtain a better smoke suppression effect.

Preferably, the PBT has an intrinsic viscosity of 0.7-1.3 dL/g at 25 ℃, and the PET has an intrinsic viscosity of 0.5-0.8 dL/g at 25 ℃. The intrinsic viscosity test method is in accordance with GB/T14190-2017.

At the intrinsic viscosity range, the PBT/PET compound can obtain better comprehensive performance.

The brominated flame retardant can be a commonly used brominated flame retardant in a PBT or PET system, such as macromolecular brominated epoxy, brominated polystyrene, brominated polycarbonate flame retardant, decabromodiphenyl ether and the like.

Preferably, the brominated flame retardant is one or more of high-molecular brominated epoxy, brominated polystyrene and brominated polycarbonate flame retardant. These brominated flame retardants are more environmentally friendly.

Preferably, the synergistic flame retardant is antimony white.

Preferably, the weight ratio of the brominated flame retardant to the synergistic flame retardant is (2-4): 1.

Preferably, the glass fibers are treated with a coupling agent.

More preferably, the coupling agent is a blend of N- (beta-aminoethyl) -gamma-aminopropyltrimethoxysilane, gamma-methacryloxypropyltrimethoxysilane, and isopropylbis (methacryloyl) isostearyl titanate in a weight ratio of 1: 2: 1.

Preferably, the epoxy resin is bisphenol A type glycidyl ether, and the epoxy equivalent is 2500-3100 g/eq. The epoxy equivalent test method is in accordance with GB/T4612-2008.

The addition of the epoxy resin can obviously improve the performance stability of the PBT/PET compound.

The invention also provides a preparation method of the low-smoke density halogen-containing flame-retardant reinforced PBT/PET compound, which comprises the following steps:

mixing a brominated flame retardant and a synergistic flame retardant to prepare a first premix;

mixing the epoxy resin with boehmite, kaolin, and magnesium stearate to form a second premix;

and adding the PBT, the PET, the glass fiber, the first premix and the second premix into an extruder, and mixing, dispersing, melting, extruding and granulating to obtain the low-smoke-density halogen-containing flame-retardant reinforced PBT/PET compound.

Preferably, the extruder is a twin screw extruder.

More preferably, the temperature of the twin-screw extruder from the feeding port to the head in the first zone is 200-230 ℃, the temperature of the twin-screw extruder in the second zone is 240-260 ℃, the temperature of the third zone is 235-255 ℃, the temperature of the fourth zone is 235-255 ℃, the temperature of the fifth zone is 235-255 ℃, the temperature of the sixth zone is 240-260 ℃, the temperature of the seventh zone is 240-260 ℃, the temperature of the eighth zone is 220-240 ℃, the temperature of the ninth zone is 220-240 ℃, the temperature of the tenth zone is 240-260 ℃, and the screw rotating speed of the twin-screw extruder is 200-450 revolutions per minute.

The invention also protects the application of the low-smoke density halogen-containing flame-retardant reinforced PBT/PET compound in the preparation of plastic parts of rail transit, building materials or cables.

Compared with the prior art, the invention has the beneficial effects that:

the invention develops a halogen-containing flame-retardant reinforced PBT/PET compound with low smoke density and good surface gloss. The smoke density of the PBT/PET compound reaches grade 3 of the smoke density required by EN45545-2 standard, the smoke density Ds max of ISO5659-2 test is less than or equal to 150, and meanwhile, the PET/PET product prepared by using the PBT/PET compound has high appearance glossiness. The low-smoke density halogen-containing flame-retardant reinforced PBT/PET compound is suitable for occasions with extremely high requirements on smoke density and good appearance.

Detailed Description

The present invention will be further described with reference to the following embodiments.

The raw materials in the examples are all commercially available;

reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated.

Examples 1 to 18

The contents of the components in the PBT/PET composites of examples 1 to 18 are shown in Table 1.

The preparation method comprises the following steps: mixing a brominated flame retardant with a synergistic flame retardant according to table 1 to make a first premix; mixing the epoxy resin with boehmite, kaolin, and magnesium stearate to form a second premix; and adding the PBT, the PET, the glass fiber, the first premix and the second premix into a double-screw extruder, and mixing, dispersing, melting, extruding and granulating to obtain the low-smoke-density halogen-containing flame-retardant reinforced PBT/PET compound.

The temperature of a first zone from a feeding port to a machine head of the double-screw extruder is 200-230 ℃, the temperature of a second zone is 240-260 ℃, the temperature of a third zone is 235-255 ℃, the temperature of a fourth zone is 235-255 ℃, the temperature of a fifth zone is 235-255 ℃, the temperature of a sixth zone is 240-260 ℃, the temperature of a seventh zone is 240-260 ℃, the temperature of an eighth zone is 220-240 ℃, the temperature of a ninth zone is 220-240 ℃, the temperature of a tenth zone is 240-260 ℃, and the screw rotating speed of the double-screw extruder is 200-450 revolutions per minute.

TABLE 1 component content (parts by weight) of PBT/PET composite of examples 1 to 18

TABLE 1 component content (parts by weight) of PBT/PET composites of examples 1 to 18

Comparative examples 1 to 8

The contents of the components in the PBT/PET composites of comparative examples 1 to 8 are shown in Table 2.

TABLE 2 component contents (parts by weight) of PBT/PET composites of comparative examples 1 to 8

Performance testing

The PBT/PET compound prepared in the above examples and comparative examples was tested for properties according to the following test methods:

gloss: injecting the PBT/PET compound into a color plate with a smooth surface, and testing by using a gloss meter, wherein the incidence angle is 60 degrees, and the size of the color plate is more than or equal to 60 x 60 mm;

flame retardancy @1.0 mm: UL94: 2003;

smoke density Ds max @1.0 mm: ISO5659-2: 2012.

Test results

The results of the performance tests of the PBT/PET composites of the examples are shown in Table 3, and the results of the performance tests of the comparative PBT/PTT composites are shown in Table 4.

TABLE 3 results of the Performance test of examples 1 to 18

As can be seen from Table 3, the PBT/PET composites prepared in the examples of the present application all had good gloss, flame retardancy of V0, and smoke density reaching the smoke density grade 3 standard required by EN45545-2 standard. According to the embodiments 1 and 6 to 9, when boehmite, kaolin and magnesium stearate are compounded in the weight ratio of 1: 1 (1-2) to 1, the low-smoke-density halogen-containing flame-retardant reinforced PBT/PET compound has lower smoke density. According to the embodiments 1 and 12 to 14, the boehmite average grain size is preferably 10 to 20nm, and the kaolin particle size is preferably D₅₀Less than or equal to 0.5 mu m, and the preferable pH value of the kaolin is 4-5.

TABLE 4 Performance test results for comparative examples 1-8

	1	2	3	4	5	6	7	8
									Degree of gloss	71	70	71	69	71	48	45	69
Flame retardancy	V0	V0	V0	V0	V0	V0	V0	HB
									Density of smoke	359	362	357	396	195	178	135	236

According to the test results in Table 4, according to comparative examples 1-4, when one or more of boehmite, kaolin and magnesium stearate is/are lack of one component, the PBT/PET compound has good flame retardance and glossiness, but has high smoke density, and Ds max is not less than or equal to 350, so that the requirement of low smoke density cannot be met. From comparative example 5, when the particle size of magnesium stearate is too high, the smoke density is 189, and the smoke density grade 3 required by EN45545-2 standard is not achieved. Compared with the comparative examples 6-7, when the weight ratio of the PBT to the PET is beyond the range of the technical scheme, the glossiness of the PBT/PET compound is poor. Compared with the comparative example 8, the addition amount of PBT and PET is too large, and the flame retardance of the PBT/PET compound is HB, so that the actual flame retardant requirement cannot be met.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. The low-smoke-density halogen-containing flame-retardant reinforced PBT/PET compound is characterized by comprising the following components in parts by weight:

15-50 parts of PBT, 8-30 parts of PET, 10-40 parts of glass fiber, 10-16 parts of a brominated flame retardant, 3-7 parts of a synergistic flame retardant, 0.5-1 part of epoxy resin, 2-4 parts of boehmite, 2-8 parts of kaolin and 2-4 parts of magnesium stearate;

the weight ratio of the PBT to the PET is (1-4) to 1,

particle size D of the magnesium stearate₅₀Less than or equal to 5 mu m; the average grain size of the boehmite is 10-20 nm; the particle diameter of the kaolin is D₅₀Less than or equal to 0.5 mu m; the pH value of the kaolin is 4-5.

2. The low-smoke density halogen-containing flame-retardant reinforced PBT/PET compound as claimed in claim 1, wherein the weight ratio of boehmite, kaolin and magnesium stearate is 1: 1 (1-2).

3. The low-smoke density halogen-containing flame-retardant reinforced PBT/PET compound of claim 1, wherein the intrinsic viscosity of the PBT is 0.7-1.3 dL/g at 25 ℃, and the intrinsic viscosity of the PET is 0.5-0.8 dL/g at 25 ℃.

4. The low-smoke density halogen-containing flame-retardant reinforced PBT/PET compound as claimed in claim 1, wherein the brominated flame retardant is one or more of high-molecular brominated epoxy, brominated polystyrene and brominated polycarbonate flame retardant.

5. The low-smoke density halogen-containing flame-retardant reinforced PBT/PET compound as claimed in claim 1, wherein the epoxy resin is bisphenol A glycidyl ether, and the epoxy equivalent is 2500-3100 g/eq.

6. The preparation method of the low-smoke density halogen-containing flame-retardant reinforced PBT/PET compound of any one of claims 1 to 5, characterized by comprising the following steps:

7. Use of the low smoke density halogen containing flame retardant reinforced PBT/PET compound of any one of claims 1 to 5 in the preparation of plastic parts for rail transit, building materials or cables.