A flame-retardant PBT composition, its preparation method and application

Abstract

The present invention discloses a flame-retardant PBT composition, which comprises the following components by weight: 80 parts of PBT resin, 6-20 parts of brominated polymer flame retardant, 1-11 parts of antimony-containing flame retardant synergist, and also comprises azine molecules, wherein the weight part of the azine molecules is 0.5-20 wt% of the brominated polymer flame retardant. By adding a specific content of azine molecules, the present invention can effectively improve the precipitation of the brominated polymer flame retardant.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly relates to a flame-retardant PBT composition, a preparation method thereof, and an application thereof. Background Art

[0002] PBT is an engineering plastic with excellent properties, having many advantages such as high mechanical strength, good fatigue resistance, good dimensional stability, and good solvent resistance, and is widely used in industries such as electronics and electrical appliances, household appliances, automobiles, and textiles. PBT is a semi-crystalline polymer with a relatively fast crystallization rate and good crystallization properties, and thus has good performance in molding processing. Usually, in product applications, higher requirements are placed on material properties, so various modification aids, fillers, etc. are blended to improve the properties of PBT materials and broaden the application fields.

[0003] Flame-retardant modification is common, but due to the differences in molecular structure characteristics and fluidity between flame-retardant molecules and polymers, problems such as precipitation will occur during actual applications, especially during long-term high-temperature service. This will not only cause deterioration of the surface appearance of the parts, but also greatly reduce the flame-retardant properties of the material, bringing adverse effects to the long-term application safety of the material.

[0004] In order to improve the long-term service performance of flame-retardant PBT materials and solve the problem of flame-retardant precipitation during long-term high-temperature service, usually the method of externally blending other components is adopted to improve the compatibility between the flame retardant and the PBT resin. For example, in patent CN109957222, low-melting-point PBT is blended in the PBT material to improve the compatibility between the flame retardant and the polymer resin matrix and reduce the risk of flame retardant precipitation; however, although externally blending other less crystalline or amorphous resins can improve the compatibility, it will lead to a decrease in the mechanical properties of the material;. In patent CN1569959, a multi-functional group grafted complex and a dispersant are blended in the PBT flame-retardant reinforced composite material. The multi-functional group grafted complex reacts with the terminal carboxyl group of PBT to form a chemical bond to enhance the binding force between the two, obtaining an alloy material with better compatibility with the flame retardant. The dispersant further strengthens the dispersion uniformity and binding strength, greatly reducing the risk of material property deterioration in a humid and hot environment; however, adding grafted complexes, etc. will also cause similar problems of performance decline, and although the reactive dispersant can improve the binding force through reaction, in a complex and diverse processing environment, the stability and reactivity of the reactive functional groups are difficult to guarantee, so problems such as low reaction efficiency often occur. In patent CN114230985, the flame retardant needs to be specially pretreated and irradiated with special γ-rays in an oxidizing atmosphere to achieve the purpose of anti-precipitation of the flame retardant. However, although the pretreatment of the flame retardant can improve the reaction activity, the pretreatment method is relatively complex and is not conducive to large-scale industrial production and popularization. Summary of the Invention

[0005] The object of the present invention is to provide a flame-retardant PBT composition with less precipitation of brominated flame retardants.

[0006] The present invention is achieved by the following technical solutions:

[0007] A flame-retardant PBT composition, by weight, comprises the following components: 80 parts of PBT resin, 6 - 20 parts of brominated high-molecular flame retardant, 1 - 11 parts of antimony-containing flame-retardant synergist, and also includes azine molecules, wherein the weight part of azine molecules is 0.5 - 20 wt% of the brominated high-molecular flame retardant. The weight part of the brominated high-molecular flame retardant can be 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, etc., as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the said range.

[0008] The weight part of the antimony-containing flame-retardant synergist can be 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, etc., as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the said range.

[0009] The weight-average molecular weight of the brominated high-molecular flame retardant is generally greater than 10000 g / mol. The weight-average molecular weight of the brominated high-molecular flame retardant is obtained by referring to the GB / T 36214.1 - 2018 standard for testing. In a specific embodiment provided by the present invention, the brominated high-molecular flame retardant is selected from at least one of brominated epoxy, brominated polystyrene, polybrominated styrene, brominated polycarbonate, and pentabromobenzyl acrylate.

[0010] The antimony-containing flame-retardant synergist is selected from at least one of sodium antimonate and antimony oxide. The antimony oxide can be antimony trioxide.

[0011] Brominated polystyrene is a brominated product of polystyrene, and polybrominated styrene is a product of polymerization of brominated styrene monomers.

[0012] In a specific embodiment provided by the present invention, the weight-average molecular weight range of the brominated high-molecular flame retardant is 13000 - 60000 g / mol. Preferably, the weight-average molecular weight range of the brominated high-molecular flame retardant is 20000 - 35000 g / mol.

[0013] Preferably, the weight part of azine molecules is 1 - 15 wt% of the brominated high-molecular flame retardant, and more preferably 2 - 10 wt%.

[0014] Azine molecules mainly refer to unsaturated heterocyclic compounds containing one or several nitrogen atoms. For example, azine compounds can be pyridine or azobenzene molecules containing one nitrogen atom; or pyridazine, pyrimidine, pyrazine or diazine or dibenzodiazine molecules containing two nitrogen atoms; or triazine or tribenzotriazine molecules containing three nitrogen atoms, tetrazine or tetrazabenzene molecules containing four nitrogen atoms, pentazine or pentazabenzene molecules containing five nitrogen atoms; or oxazine or oxazoline molecules containing one nitrogen atom and one oxygen atom; or thiazine or thiazoline molecules containing one sulfur atom and one nitrogen atom.

[0015] The present invention does not particularly limit azine molecules. In a specific embodiment provided by the present invention, the azine molecules are selected from at least one of 3,7-diamino-5-phenylphenazinium chloride, [4-[(4-dimethylaminophenyl)-(4-methylaminophenyl)methylene]-1-cyclohexane-2,5-diene]-dimethyl azo, Solvent Black 1, Solvent Black 3, Solvent Black 5, Solvent Black 7, Solvent Black 17, and Solvent Black 27.

[0016] Preferably, the azine molecule is selected from 3,7-diamino-5-phenylphenazinium chloride.

[0017] The CAS number of 3,7-diamino-5-phenylphenazinium chloride is 81-93-6;

[0018] [4-[(4-dimethylaminophenyl)-(4-methylaminophenyl)methylene]-1-cyclohexane-2,5-diene]-dimethyl azo has a CAS number of 8004-87-3;

[0019] The CAS number of Solvent Black 7 is 8005-02-5.

[0020] The present invention does not particularly limit the intrinsic viscosity of the PBT resin. As long as the intrinsic viscosity of the PBT resin is in the range of 0.8-1.0 dl / g, the technical effects of the present invention can be achieved. Among them, the intrinsic viscosity is measured according to standard GB / T 14190-2017.

[0021] The preparation method of the PBT composition of the present invention includes the following steps: adding each component to a twin-screw extruder. The temperature range of the twin-screw extruder is 200-250 °C, and the rotation speed is 250-400 revolutions per minute, and granulation is carried out to obtain the PBT composition.

[0022] The application of the PBT composition of the present invention is used for preparing new energy vehicle battery parts, such as vehicle bases, etc.

[0023] The present invention has the following beneficial effects. By adding azine molecules to the brominated flame retardant PBT composition and preferably controlling their molecular weight and addition ratio, the amino groups in the azine molecules can stabilize the bromine atoms in the brominated flame retardant, reduce polarity, improve the long-term compatibility between the flame retardant and PBT, reduce the risk of flame retardant precipitation during long-term use and aging, and enhance the long-term flame retardancy performance. Embodiment

[0024] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any way. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made. These all fall within the protection scope of the present invention.

[0025] The sources of the raw materials used in the present invention are as follows:

[0026] PBT resin A: Intrinsic viscosity 0.82 dl / g, grade PBT GX112, Sinopec Yizheng Chemical Fiber Co., Ltd.;

[0027] PBT resin B: Intrinsic viscosity 0.67 dl / g, grade PBT GX110, Sinopec Yizheng Chemical Fiber Co., Ltd.;

[0028] PBT resin C: Intrinsic viscosity 1.15 dl / g, grade PBT BM433, Sinopec Yizheng Chemical Fiber Co., Ltd.;

[0029] Azine molecule A: 3,7-diamino-5-phenylphenazinium chloride, CAS No. 81-93-6, Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0030] Azine molecule B: [4-[(4-dimethylaminophenyl)-(4-methylaminophenyl)methylene]-1-cyclohexane-2,5-diene]-dimethyl azo, CAS No. 8004-87-3, Taizhou Dongbang Fine Chemical Co., Ltd.;

[0031] Azine molecule C: Solvent Black 7, CAS No. 8005-02-5, Shanghai Merck Chemical Technology Co., Ltd.;

[0032] Azine molecule D: Solvent Black 1, CAS 13007-86-8, Hubei Wande Chemical Industry Co., Ltd.;

[0033] Azine molecule E: Solvent Black 3, CAS 4197-25-5, Shanghai Merck Chemical Technology Co., Ltd.;

[0034] Flame Retardant A: Brominated epoxy, EP-25K, weight-average molecular weight 25000 g / mol, Jiangsu Xingsheng Chemical Co., Ltd.;

[0035] Flame Retardant B: Brominated epoxy, EP-30K, weight-average molecular weight 30000 g / mol, Jiangsu Xingsheng Chemical Co., Ltd.;

[0036] Flame Retardant C: Brominated epoxy, EP-15K, weight-average molecular weight 15000 g / mol, Jiangsu Xingsheng Chemical Co., Ltd.;

[0037] Flame Retardant D: Brominated epoxy, EP-50K, weight-average molecular weight 50000 g / mol, Jiangsu Xingsheng Chemical Co., Ltd.;

[0038] Flame Retardant E: Brominated polystyrene, BPS 301, 40000 g / mol, Shandong Tianyi Chemical Co., Ltd.;

[0039] Flame Retardant F: Poly(brominated styrene), PBS-64HW, 60000 g / mol, LANXESS Chemical, Germany;

[0040] Flame Retardant G: Decabromodiphenylethane, SAYTEX 8010, 971 g / mol, Albemarle Chemical, USA;

[0041] Antimony trioxide: S-05N, Changde Chenzhou Antimony Products Co., Ltd.

[0042] Preparation method of PBT compositions in examples and comparative examples: Add each component into a twin-screw extruder. The temperature of the twin-screw extruder is set as follows: the temperature of zone 1 is 220 - 240 °C, the temperature of zone 2 is 230 - 245 °C, the temperature of zone 3 is 235 - 245 °C, the temperature of zone 4 is 235 - 250 °C, the temperature of zone 5 is 220 - 240 °C, the temperature of zone 6 is 220 - 240 °C, the temperature of zone 7 is 210 - 230 °C, the temperature of zone 8 is 200 - 220 °C, the temperature of zone 9 is 200 - 220 °C, the temperature of zone 10 is 220 - 240 °C, and the rotation speed is 250 - 400 revolutions per minute. Granulate to obtain the PBT composition.

[0043] Testing methods for each item:

[0044] (1) Flame retardancy: Test according to standard UL 94-2021, test the vertical burning rating of 0.8 mm thick specimens. The afterflame time after the first ignition is recorded as t1, and the afterflame time after the second ignition is recorded as t2.

[0045] (2) Flame retardancy after aging: After aging the 0.8 mm specimens at 120 °C for 120 hours, test the vertical burning rating according to standard UL 94-2021.

[0046] Table 1: Component contents (parts by weight) and test results of PBT compositions in Examples 1-8

[0047] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 PBT-A 80 80 80 80 80 80 80 PBT-B 80 PBT-C 80 Flame retardant A 10 6 20 10 10 10 10 10 10 Antimony trioxide 3 1 11 3 3 3 3 3 3 Azine molecule A 0.05 0.03 0.1 0.1 0.2 0.5 1 1.5 2 t1 + t2 / s 1.5 5.1 2.1 1.5 0.3 0.1 0.3 1.1 1.8 Flammability V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 t1 + t2 / s after aging 3.2 8.8 4.0 3.8 0.6 0.4 1 2.2 4.5 Flammability after aging V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0

[0048] As can be seen from Examples 1 / 4-9, when the ratio of the preferred azine molecules is used, not only is the flame retardancy better, but the anti-aging precipitation performance is also better (manifested as better flame retardancy after aging).

[0049] Table 2: Component contents (parts by weight) and test results of PBT compositions in Examples 10-14

[0050] Example 10 Example 11 Example 12 Example 13 Example 14 PBT-A 80 80 80 80 80 Flame retardant B 10 Flame retardant C 10 Flame retardant D 10 Flame retardant E 10 Flame retardant F 10 Antimony trioxide 3 3 3 3 3 Azine molecule A 0.5 0.5 0.5 0.5 0.5 t1 + t2 / s 0.2 1.4 1.6 2.6 3.3 Flammability V-0 V-0 V-0 V-0 V-0 t1 + t2 / s after aging 0.4 4.1 4.8 5.3 4.7 Flammability after aging V-0 V-0 V-0 V-0 V-0

[0051] As can be seen from Examples 6 / 10-12, when the molecular weight range of the preferred brominated polymer flame retardant is 20,000-35,000 g / mol, the flame retardancy and anti-aging precipitation performance are better.

[0052] Table 3: Component contents (parts by weight) and test results of PBT compositions in Examples 15-18

[0053] Example 15 Example 16 Example 17 Example 18 PBT-A 80 80 80 80 Flame retardant A 10 10 10 10 Antimony trioxide 3 3 3 3 Azine molecule B 0.5 Azine molecule C 0.5 Azine molecule D 0.5 Azine molecule E 0.5 t1 + t2 / s 0.9 0.7 0.9 1.1 Flammability V-0 V-0 V-0 V-0 t1 + t2 / s after aging 2.3 1.6 1.9 2.2 Flammability after aging V-0 V-0 V-0 V-0

[0054] As can be seen from Examples 6 / 15-18, the preferred azine molecule is 3,7-diamino-5-phenylphenazinium chloride.

[0055] Table 4: Component contents (parts by weight) and test results of PBT compositions in Comparative Examples

[0056] Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 PBT-A 80 80 80 80 Flame retardant A 10 10 10 Flame retardant G 10 Antimony trioxide 3 3 3 3 Azine molecule A 0.5 0.02 2.5 t1 + t2 / s 1.6 1.5 1.5 2.2 Flammability V-0 V-0 V-0 V-0 t1 + t2 / s after aging 33.5 36.8 31.7 7.3 Drop ignition Flammability after aging V-2 V-2 V-2 V-2

[0057] As can be seen from Comparative Example 1, the azine molecules have insufficient ability to prevent the precipitation of low-molecular brominated flame retardants.

[0058] As can be seen from Comparative Examples 2-4, when azine molecules are not added or the content is too low or too high, the flame retardancy after aging is also poor.

[0059] From the data of the above examples and comparative examples, it can be seen that the technical solution of the present application has the technical effects of V-0 flame retardancy and t1 + t2 < 10 s after aging.

Claims

1. A flame-retardant PBT composition, characterized in that, by weight, it comprises the following components: 80 parts of PBT resin, 6 - 20 parts of brominated high molecular flame retardant, 1 - 11 parts of antimony-containing flame retardant synergist, and also comprises azine molecules, wherein the weight part of azine molecules is 0.5 - 20wt% of the brominated high molecular flame retardant; The brominated high molecular flame retardant is selected from at least one of brominated epoxy, brominated polystyrene, polybrominated styrene, brominated polycarbonate, and pentabromobenzyl acrylate; The azine molecules are selected from at least one of 3,7-diamino-5-phenylphenazinium chloride, [4-[(4-dimethylaminophenyl)-(4-methylaminophenyl)methylene]-1-cyclohexane-2,5-diene]-dimethyl azo, Solvent Black 1, Solvent Black 3, Solvent Black 5, Solvent Black 7, Solvent Black 17, and Solvent Black 27.

2. The flame-retardant PBT composition according to claim 1, characterized in that, The antimony-containing flame retardant synergist is selected from at least one of sodium antimonate and antimony oxide.

3. The flame-retardant PBT composition according to claim 2, characterized in that, The weight-average molecular weight range of the brominated high molecular flame retardant is 13000 - 60000 g / mol.

4. The flame-retardant PBT composition according to claim 3, characterized in that, The weight-average molecular weight range of the brominated high molecular flame retardant is 20000 - 35000 g / mol.

5. The flame-retardant PBT composition according to claim 1, characterized in that, The weight part of azine molecules is 1 - 15wt% of the brominated high molecular flame retardant.

6. The flame-retardant PBT composition according to claim 5, characterized in that, The weight part of azine molecules is 2 - 10wt% of the brominated high molecular flame retardant.

7. The flame-retardant PBT composition according to claim 6, characterized in that, The azine molecules are selected from 3,7-diamino-5-phenylphenazinium chloride.

8. The flame-retardant PBT composition according to claim 1, characterized in that, The intrinsic viscosity range of the PBT resin is 0.8 - 1.0 dl / g, and the intrinsic viscosity is tested according to standard GB / T 14190 - 2017.

9. The preparation method of the PBT composition according to any one of claims 1 - 8, characterized in that, comprises the following steps: Adding each component into a twin-screw extruder, the temperature range of the twin-screw extruder is 200 - 250°C, the rotation speed is 250 - 400 revolutions per minute, and granulation is carried out to obtain the PBT composition.

10. The application of the PBT composition according to any one of claims 1 - 8, characterized in that, It is used for preparing new energy vehicle battery parts.