PBT composite material containing halogen-free flame retardant and preparation method thereof

Abstract

The application discloses a PBT composite material containing halogen-free flame retardant and a preparation method thereof. The PBT composite material containing halogen-free flame retardant comprises the following components: PBT, PETG, a novel phosphorus-silicon flame retardant and a silane coupling agent. The novel phosphorus-silicon flame retardant prepared by the application contains a large amount of organic silicon elements and organic phosphorus elements, and the silicon and phosphorus elements are combined by covalent bonds, so that the structure is stable. Under the action of the silane coupling agent, the silicon and phosphorus elements can be effectively bonded with the PBT and PETG, so that the flame retardant performance of the PBT composite material is significantly improved.

Description

Technical Field

[0001] This invention belongs to the field of polymer composite material technology, specifically relating to a PBT composite material containing a halogen-free flame retardant and its preparation method. Background Technology

[0002] Polybutylene terephthalate (PBT) is a polyester produced by the condensation polymerization of terephthalic acid and 1,4-butanediol. It is an important thermoplastic polyester and one of the five major engineering plastics. PBT is a milky white, translucent to opaque, semi-crystalline thermoplastic polyester with high heat resistance. It is not resistant to strong acids and alkalis, but is resistant to organic solvents. These excellent properties have led to its widespread use in the automotive, machinery, precision instrument components, electronics, and textile industries. However, its limiting oxygen index (LOI) of 20%-22% makes it easily combustible in air, difficult to char, and prone to continuous dripping during combustion, which can easily spread the flame and cause a fire, thus limiting its application range to some extent.

[0003] Therefore, to meet the flame-retardant performance requirements of polymer materials in products, effective flame-retardant modification of PBT is necessary. Halogenated flame retardants have been widely used in the past, but their adverse environmental impacts and safety hazards have become increasingly apparent. Halogenated flame retardants may produce toxic and corrosive gases during combustion, causing environmental pollution and posing a threat to human health. With the EU's WEEE and RoHS directives published in 2003, which mandated halogen-free materials used in the electronics, electrical, information, and office appliance industries, the introduction of these directives has spurred the research and development of halogen-free flame-retardant PBT composite materials. In the selection of halogen-free flame retardants, commonly used halogen-free flame retardants for thermoplastic polyesters such as PBT mainly include phosphorus-based, phosphorus-nitrogen-based, organosilicon-based, and inorganic flame retardants. Among these halogen-free flame retardants, phosphorus-based and organosilicon-based flame retardants have attracted much attention due to their unique flame retardant mechanisms. However, there are few existing flame retardants that combine phosphorus-based and organosilicon-based flame retardants. Therefore, in order to improve the flame retardancy of PBT materials and further expand their application range, it is necessary to invent a new PBT composite material containing halogen-free flame retardants and its preparation method. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a PBT composite material containing a halogen-free flame retardant and its preparation method.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] On the one hand, this application provides a PBT composite material containing a halogen-free flame retardant, characterized in that, by weight, it comprises the following components:

[0007]

[0008] The structural formula of the novel phosphorus-silicon flame retardant M1 is shown in formula (I):

[0009]

[0010] Further, the PBT is 100 parts, the PETG is 1-20 parts, the novel phosphorus-silicon flame retardant M1 is 1-20 parts, and the silane coupling agent is 3-7 parts;

[0011] Further, the PBT is 100 parts, the PETG is 5-15 parts, the novel phosphorus-silicon flame retardant M1 is 5-20 parts, and the silane coupling agent is 3-7 parts;

[0012] Further, the PBT is 100 parts, the PETG is 8-12 parts, the novel phosphorus-silicon flame retardant M1 is 5-15 parts, and the silane coupling agent is 4-6 parts;

[0013] Furthermore, the silane coupling agent includes one or more of KH550, KH560, KH570, KH792, and DL602.

[0014] On the other hand, this application also provides a method for preparing a PBT composite material containing a halogen-free flame retardant, characterized by comprising the following steps:

[0015] Take PBT, PETG and a novel phosphorus-silicon flame retardant, disperse them evenly, then add a silane coupling agent, mix evenly and granulate to obtain a PBT composite material containing a halogen-free flame retardant.

[0016] The structural formula of the novel phosphorus-silicon flame retardant is shown in formula (I):

[0017]

[0018] Further, the PBT is 100 parts, the PETG is 1-30 parts, the novel phosphorus-silicon flame retardant is 0.1-20 parts, and the silane coupling agent is 1-10 parts;

[0019] Further, the PBT is 100 parts, the PETG is 1-20 parts, the novel phosphorus-silicon flame retardant M1 is 1-20 parts, and the silane coupling agent is 3-7 parts;

[0020] Further, the PBT is 100 parts, the PETG is 5-15 parts, the novel phosphorus-silicon flame retardant M1 is 5-20 parts, and the silane coupling agent is 3-7 parts;

[0021] Further, the PBT is 100 parts, the PETG is 8-12 parts, the novel phosphorus-silicon flame retardant M1 is 5-15 parts, and the silane coupling agent is 4-6 parts;

[0022] Furthermore, the silane coupling agent includes one or more of KH550, KH560, KH570, KH792, and DL602;

[0023] Furthermore, the preparation method of the novel phosphorus-silicon flame retardant includes the following steps:

[0024] 1,3,5-tris(dimethylchlorosilyl)benzene and an organic base were added to a solvent, and then diphenyl phosphate was added. After the reaction was completed, the mixture was separated and purified to obtain the novel phosphorosilicon flame retardant.

[0025] Further, the molar ratio of the diphenyl phosphate to the 1,3,5-tris(dimethylchlorosilyl)benzene is 2-4:1;

[0026] Furthermore, the molar ratio of the diphenyl phosphate to the 1,3,5-tris(dimethylchlorosilyl)benzene is 3-4:1;

[0027] Furthermore, the reaction temperature is 15-30℃, and the reaction time is 12-36h;

[0028] Furthermore, the reflux reaction is carried out at a temperature of 20-25°C for 18-30 hours.

[0029] Furthermore, the solvent includes at least one of 1,4-dioxane, acetonitrile, carbon tetrachloride, toluene, 1,2-dichloroethane, chlorobenzene, DMSO, DMF, and chloroform.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] This invention discloses a PBT composite material containing a halogen-free flame retardant and its preparation method. The PBT composite material containing the halogen-free flame retardant comprises the following components: PBT, PETG, a novel phosphorus-silicon flame retardant, and a silane coupling agent. Because the novel phosphorus-silicon flame retardant prepared in this application contains a large amount of organosilicon and organophosphorus elements, and the silicon and phosphorus elements contained therein are covalently bonded, exhibiting a stable structure, it can effectively bond with PBT and PETG under the action of the silane coupling agent, thereby significantly improving the flame retardant performance of the PBT composite material. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. In the description of this application, it should be understood that "and / or" describes the relationship between related objects, indicating that three relationships may exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this application, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c," or "at least one of a, b, and c," can both represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can each be single or multiple.

[0034] The present application will be specifically described below through specific embodiments. The following embodiments are only some embodiments of the present application and should not be construed as limiting the present application.

[0035] Example 1

[0036] This embodiment provides a novel phosphorus-silicon flame retardant, which is prepared through the following steps:

[0037] Under nitrogen protection at room temperature, 500 mL of 1,4-dioxane, 0.1 mol of 1,3,5-tris(dimethylchlorosilyl)benzene, and 0.3 mol of triethylamine were added to a flask. The flask was then stirred in an ice-water bath for 30 min. Within 30 min, 0.3 mol of dried diphenyl phosphate was added in portions to the reaction flask. After naturally warming to room temperature, the reaction was allowed to proceed for 24 h. The solvent was removed under reduced pressure, and the mixture was washed three times with 1 L of distilled water. Finally, the mixture was dried in a vacuum drying oven at 110 °C for 24 h to obtain a white solid, which is the novel phosphorus-silicon flame retardant with a yield of 78.5%. Its 1H NMR data are as follows: 1H NMR (400 MHz, DMSO, δ / ppm): 7.48 (s, 3H), 7.35 (m, 12H), 7.28 (d, 12H), 7.21 (d, 6H), 0.82 (s, 18H).

[0038] The synthetic route for the novel phosphorus-silicon flame retardant is shown below:

[0039]

[0040] Application Examples 1-4

[0041] Application Examples 1-4 provide a PBT composite material containing a halogen-free flame retardant, which is prepared by the following steps:

[0042] PBT (polybutylene terephthalate), PETG (polyethylene terephthalate-1,4-cyclohexanediol ester), and a novel phosphorus-silicon flame retardant were weighed and added together to a high-speed mixer. The mixture was stirred at 300 rpm for 30 minutes until it was evenly dispersed. Then, silane coupling agent KH560 was added, and the mixture was stirred at 400 rpm for 30 minutes. The blend was then extruded and granulated using a twin-screw extruder to obtain a PBT composite material containing a halogen-free flame retardant.

[0043] The component composition of Application Examples 1-4 is shown in Table 1:

[0044] Table 1

[0045]

[0046]

[0047] Comparative Example 1

[0048] The only difference from Application Example 1 is that the novel phosphorus-silicon flame retardant prepared in Example 1 is not added.

[0049] Comparative Example 2

[0050] Compared to Application Example 1, the only difference is that the silane coupling agent KH560 is not added.

[0051] Flame retardant performance test:

[0052] (1) Oxygen Index (LO I) Test: The oxygen index of the samples was tested according to the national standard GB / T 2406.2-2009, which is the determination method of the burning performance of plastics. The average value of 5 samples after burning was taken as the limit index of PBT composite material containing halogen-free flame retardant. The test results are shown in Table 2.

[0053] (2) Vertical flammability test The vertical flammability test is based on the national standard GB / 2408-2008 Test method for the flammability of plastics. The test results are shown in Table 2.

[0054] Mechanical property testing:

[0055] The tensile strength and elongation at break of the specimens were determined according to the national standard GB / T 1040.2-2006 "Test Method for Tensile Properties of Plastics". The tensile speed was 50 mm / min. To ensure the accuracy of the experiment, five specimens were taken for each component, and the average value method was used to process the data. The test results are shown in Table 2.

[0056] Table 2

[0057]

[0058]

[0059] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application, and the scope of protection of this invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A PBT composite material containing a halogen-free flame retardant, characterized in that, By weight, it consists of the following components: 100 copies of PBT; PETG 5-15 servings; 5-20 parts of phosphorus-silicon flame retardant; 3-7 parts of silane coupling agent; The structural formula of the phosphorus-silicon flame retardant is shown in formula (I): Equation (I).

2. The PBT composite material containing a halogen-free flame retardant according to claim 1, characterized in that, The silane coupling agent includes one or more of KH550, KH560, KH570, KH792, and DL602.

3. The PBT composite material containing a halogen-free flame retardant according to any one of claims 1-2, characterized in that, The PBT is 100 parts, the PETG is 8-12 parts, the phosphorus-silicon flame retardant is 5-15 parts, and the silane coupling agent is 4-6 parts.

4. A method for preparing a PBT composite material containing a halogen-free flame retardant, characterized in that, Includes the following steps: Take PBT, PETG and phosphorus silicon flame retardant, disperse them evenly, then add silane coupling agent, mix evenly and granulate to obtain PBT composite material containing halogen-free flame retardant. The structural formula of the phosphorus-silicon flame retardant is shown in formula (I): Equation (I) Of which, by weight, the PBT is 100 parts, the PETG is 5-15 parts, the phosphorus-silicon flame retardant is 5-20 parts, and the silane coupling agent is 3-7 parts.

5. The method for preparing the PBT composite material containing a halogen-free flame retardant according to claim 4, characterized in that, The silane coupling agent includes one or more of KH550, KH560, KH570, KH792, and DL602.

6. The method for preparing the PBT composite material containing a halogen-free flame retardant according to claim 4, characterized in that, The PBT is 100 parts, the PETG is 8-12 parts, the phosphorus-silicon flame retardant is 5-15 parts, and the silane coupling agent is 4-6 parts.

7. The method for preparing the PBT composite material containing a halogen-free flame retardant according to claim 4, characterized in that, The preparation method of the phosphorus silicon flame retardant includes the following steps: 1,3,5-tris(dimethylchlorosilyl)benzene and an organic base were added to a solvent, followed by the addition of diphenyl phosphate. The reaction was carried out, and the mixture was separated and purified after the reaction to obtain the phosphorosilicon flame retardant.

8. The method for preparing the PBT composite material containing a halogen-free flame retardant according to claim 7, characterized in that, The molar ratio of the diphenyl phosphate to the 1,3,5-tris(dimethylchlorosilyl)benzene is 2-4:1; And / or, the reaction temperature is 15-30℃ and the reaction time is 12-36h.

9. The method for preparing the PBT composite material containing a halogen-free flame retardant according to claim 7, characterized in that, The solvent includes at least one of 1,4-dioxane, acetonitrile, carbon tetrachloride, toluene, 1,2-dichloroethane, chlorobenzene, DMSO, DMF, and chloroform; And / or, the organic base includes one or more of trimethylamine, triethylamine, pyridine, and N,N-diisopropylethylamine.

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