CN110734551B

CN110734551B - High-strength high-heat-resistance flame-retardant transparent polycarbonate resin and preparation method thereof

Info

Publication number: CN110734551B
Application number: CN201910908417.0A
Authority: CN
Inventors: 张瑾; 朱佳虹; 李锦平; 李淑杰; 谷松
Original assignee: Jinxi Research Institute Of Chemical Industry Co ltd
Current assignee: Jinxi Research Institute Of Chemical Industry Co ltd
Priority date: 2019-09-25
Filing date: 2019-09-25
Publication date: 2022-05-13
Anticipated expiration: 2039-09-25
Also published as: CN110734551A

Abstract

The invention provides a high-strength, high-heat-resistant and flame-retardant transparent polycarbonate and a preparation method thereof. The phosphorus-silicon flame retardant is prepared by modifying DOPO (9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) by using allyl alcohol and reacting the modified structure with phenyl hydrogen-containing silicon resin. Phosphorus and silicon elements are simultaneously introduced into the flame retardant structure, and are added into polycarbonate resin, so that the thermal stability and the mechanical strength of the polycarbonate material are improved on the premise of not influencing the transmittance. The preparation process is simple, halogen-free and environment-friendly, and has great market popularization value.

Description

High-strength high-heat-resistance flame-retardant transparent polycarbonate resin and preparation method thereof

Technical Field

The invention relates to the field of high polymer materials, in particular to high-strength, high-heat-resistant and flame-retardant transparent polycarbonate and a preparation method thereof.

Background

Polycarbonate (PC) is a thermoplastic engineering plastic with good comprehensive performance, and has the characteristics of excellent light transmission, impact toughness, electrical insulation, weather resistance and the like due to the structural particularity of the PC. The method is widely applied to the industries of electronics, electrical appliances, aerospace, automobiles and the like.

With the increasing development of industries such as electronic and electric appliances, aerospace, automobile components and the like, the requirement on the flame retardance of polycarbonate is more and more strict, the polycarbonate has certain flame retardance, the oxygen index of the polycarbonate can reach about 25, the polycarbonate can pass the UL 94V-2 test, but the polycarbonate needs to be subjected to flame retardant modification treatment to meet the requirement on high flame retardance.

Common flame retardants include halogens, phosphorus, silicon, sulfonate, and the like. Halogen flame retardants can seriously affect the light transmittance and impact strength of PC, sulfonate flame retardants have good flame retardant effect and have small influence on the light transmittance of polycarbonate, but sulfonate contains sulfur element and can cause harm to the environment and human bodies. The phosphorus flame retardant has low price, good flame retardant effect, no halogen and environmental protection, but the phosphorus flame retardant has poor heat resistance and can directly influence the light transmittance of the polycarbonate when too much phosphorus flame retardant is added. The organosilicon flame retardant has the characteristics of high efficiency, no toxicity, low smoke, no dripping, small influence on light transmittance, processability, mechanical property and the like, but the use of the organosilicon flame retardant in industry is limited due to high price. Therefore, according to the current research situation, a single flame retardant cannot simultaneously satisfy the performance requirements of polycarbonate.

Disclosure of Invention

The invention aims to synthesize a novel flame retardant simultaneously containing phosphorus and silicon elements aiming at the defects of the prior art, and the novel flame retardant is added into polycarbonate resin to prepare high-strength, high-heat-resistant and flame-retardant transparent polycarbonate resin.

The invention firstly provides a preparation method of a flame retardant containing phosphorus and silicon elements, which comprises the following steps:

(1) adding a certain amount of DOPO (9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) and an organic solvent into a three-necked bottle provided with a condensing reflux device, and slowly dripping CCl under the ice bath condition₄And after the dripping is finished, continuously adding the propylene alcohol and the triethylamine into the system, reacting for a period of time, raising the temperature of the system, keeping the temperature for reacting for a period of time, then cooling to room temperature, filtering, washing and drying the crude product to obtain the propylene alcohol modified DOPO.

(2) And (2) dissolving the product obtained in the step (1) in cyclohexane, adding phenyl hydrogen-containing silicone resin, uniformly stirring, removing the solvent under reduced pressure, adding Karstedt catalyst, and reacting to obtain the target product.

The process is represented by a chemical reaction formula as follows:

the structure of the flame retardant containing phosphorus and silicon is as follows:

the organic solvent in the step (1) is one of 1,4 dioxane, chloroform, tetrahydrofuran, acetone and dichloromethane or a mixture of the two in any proportion. The proportion of DOPO and the organic solvent can be 1 g: (1-30 ml).

In the step (1), the molar ratio of DOPO to allyl alcohol is 1 (1-3).

In the step (1), the molar ratio of DOPO to carbon tetrachloride is 1: 1-3.

In the step (1), the molar ratio of DOPO to triethylamine is 1: 1-3.

The ice-bath condition in the step (1): the reaction temperature is less than 15 ℃, and the reaction time is 0.5-2 h.

And (2) heating for reaction in the step (1), wherein the reaction temperature is 20-50 ℃, and the reaction time is 4-10 hours.

In the step (2), the molar ratio of the product of the step (1) to the phenyl hydrogen-containing silicone resin is (1-6): 1.

The phenyl hydrogen-containing silicone resin in the step (2) is a commercially available product, and the trade mark is as follows: the SH-8 structure is as follows:

a preparation method of high-strength, high-heat-resistant and flame-retardant transparent polycarbonate resin comprises the following steps:

(a) preparing the following materials in percentage by weight: 80-99% of polycarbonate and 1-20% of phosphorus-silicon flame retardant;

(b) drying polycarbonate at 100-140 ℃ for 4-10 h, uniformly mixing the dried polycarbonate resin and the phosphorus-silicon flame retardant, adding the mixture into a double-screw extruder, extruding, drawing, granulating at 220-280 ℃, and drying to obtain the flame-retardant transparent polycarbonate resin material.

The phosphorus-silicon flame retardant in the step (a) is obtained by the preparation method of the flame retardant containing phosphorus and silicon elements.

The invention has the advantages and effects that:

according to the invention, a novel phosphorus-silicon-containing flame retardant is synthesized, and due to the structural particularity, the polyphenyl phosphate structure, the polyphenyl spherical siloxane structure and the like contained in the structure are added into polycarbonate resin, so that the flame retardant property and the mechanical strength of the polycarbonate are improved on the basis of not influencing the transmittance of the polycarbonate.

Detailed Description

The present invention will be described in detail with reference to examples.

EXAMPLE 1 Synthesis of phosphorus silicon flame retardant

(1) Adding 4.32g of DOPO and 20ml of dichloromethane into a three-necked bottle provided with a condensing reflux device, and slowly dropwise adding 4ml of CCl under the ice bath condition₄After the dropwise addition, continuously adding 1.2g of propylene alcohol and 4ml of triethylamine into the system, reacting for a period of time, raising the temperature of the system, keeping the temperature for reacting for a period of time, cooling to room temperature, filtering, washing and drying the crude product to obtain the propylene alcohol modified DOPO.

(2) And (2) dissolving 11.5g of the product obtained in the step (1) in cyclohexane, adding 7.52g (0.01mol) of phenyl hydrogen-containing silicone resin, uniformly stirring, removing the solvent under reduced pressure, adding a Karstedt catalyst, and finally reacting to obtain the target product.

Examples 2-6 preparation of high-Strength, high Heat-resistant, flame-retardant transparent polycarbonate resins

Examples 2-6, the weight percentages of the components in each example are shown in table 1.

The specific steps are as follows, drying the PC resin for 4 hours at the temperature of 120 ℃, and uniformly mixing the PC resin and the flame retardant according to the proportion. Adding the mixture into a double-screw extruder for melt blending extrusion; wherein the temperature of each zone of the double-screw extruder is 260 ℃, 265 ℃, 270 ℃, 270 ℃, 265 ℃ and the head temperature is 270 ℃, and the extruded raw materials are subjected to traction, granulation and drying to obtain the transparent flame-retardant PC material. The resulting transparent PC material was injection-molded into 3.0mm thick bars by means of an injection-molding machine and the performance tests were carried out according to the corresponding standards (see Table 2).

The test results are shown in Table 3.

Table 1: formulation compositions of examples 2-6

Components	Example 2	Example 3	Example 4	Example 5	Example 6
						Polycarbonate resin	98％	96％	94％	92％	90％
Phosphorus silicon flame retardant	2％	4％	6％	8％	10％

TABLE 2 test standards

Item	Unit of	Test conditions	Test standard
				Tensile strength	MPa	23℃	ASTM D 638
Elongation at break	％	50mm/min	ASTM D 638
				Impact strength	KJ/m³	23℃	ASTM D 256
UL94	3.0mm	/	ASTM 2863
				Oxygen index	％	/	ASTM 2863
Transmittance of light	％	23℃	ASTM D1003

TABLE 3 mechanical Properties and flame retardancy of polycarbonates tested in examples 2-6

Performance of	Example 2	Example 3	Example 4	Example 5	Example 6
						Tensile strength	61.6	63.7	65.5	70.1	68.9
Elongation at break	120	125	125	120	117
						Impact strength	53.8	59.6	59.9	60.5	60.7
UL-94(3mm)	V-0	V-0	V-0	V-0	V-0
						Transmittance of light	87.1	86.9	86.7	86.0	85.0

TABLE 4 thermal weight loss test data for polycarbonates of examples 2-6

Test specimen	T_-5％(℃)	T_-50％(℃)	T_-70％(℃)
				Example 2	399.7	448.2	471.4
Example 3	423 2	471.9	501.2
				Example 4	425 9	482.0	503.9
Example 5	427 0	469.1	500.1
				Example 6	415.1	449.0	479.9

As can be seen from the results of the performance tests in tables 3 and 4, the mechanical strength and the thermal stability of the polycarbonate are improved on the basis of ensuring the light transmittance of the polycarbonate by adding the phosphorus-silicon flame retardant, and the optimal formula can be determined through tests.

The present invention is further illustrated by the following specific examples, which are only exemplary and not intended to limit the scope of the present invention. It will be understood by those skilled in the art that various equivalent substitutions, modifications or improvements may be made on the technical solution of the present invention and the embodiments thereof without departing from the spirit and scope of the present invention, and these shall fall within the scope of the present invention. The scope of the invention is to be determined by the claims appended hereto.

Claims

1. A preparation method of a flame retardant containing phosphorus and silicon elements has the following structure:

(1) adding a certain amount of DOPO (9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) and an organic solvent into a three-necked bottle provided with a condensing reflux device, and slowly dripping CCl under the ice bath condition₄After the dripping is finished, continuously adding the propylene alcohol and the triethylamine into the system, reacting for a period of time, raising the temperature of the system, keeping the temperature for reacting for a period of time, then cooling to room temperature, filtering, washing and drying the crude product to obtain propylene alcohol modified DOPO;

2. The method for preparing phosphorus-silicon-element-containing flame retardant according to claim 1, wherein the organic solvent in step (1) is one or a mixture of more of 1,4 dioxane, chloroform, tetrahydrofuran, acetone and dichloromethane, and the proportion of DOPO to the organic solvent is 1 g: (1-30 ml).

3. The preparation method of the phosphorus-silicon-element-containing flame retardant according to claim 1, wherein the molar ratio of DOPO to allyl alcohol in the step (1) is 1 (1-3).

4. The method for preparing the phosphorus-silicon element-containing flame retardant according to claim 1, wherein the molar ratio of DOPO to carbon tetrachloride in the step (1) is 1: 1-3.

5. The preparation method of the flame retardant containing phosphorus and silicon elements according to claim 1, wherein the molar ratio of DOPO to triethylamine in the step (1) is 1: 1-3.

6. The method for preparing a phosphorus-silicon element-containing flame retardant according to claim 1, wherein the ice bath conditions in step (1) are as follows: the reaction temperature is less than 15 ℃, and the reaction time is 0.5-2 h; the reaction temperature of the heat preservation reaction is 20-50 ℃, and the reaction time is 4-10 h.

7. The method for preparing the phosphorus-silicon-element-containing flame retardant according to claim 1, wherein in the step (2), the molar ratio of the product of the step (1) to the phenyl hydrogen-containing silicone resin is (1-6): 1.

8. The preparation method of the phosphorus-silicon element-containing flame retardant according to claim 1, wherein the phenyl hydrosilicon resin in the step (2) has the following structure: