CN112457644B - High-toughness and high-flow flame-retardant polycarbonate composition and preparation method and application thereof - Google Patents

Abstract

The invention provides a high-toughness high-fluidity flame-retardant polycarbonate composition, which comprises the following components in parts by weight: 10-99.9 parts of polycarbonate, 0.01-30 parts of polysiloxane-polycarbonate, 0.1-2 parts of low-temperature toughening stabilizer, 0.01-1 part of reinforcing stabilizer, 0.1-5 parts of anti-dripping agent and 0.01-10 parts of flame retardant. The high-toughness high-fluidity flame-retardant polycarbonate composition has the advantages that the ASTM normal-temperature notch impact strength is more than 600J/m under the condition of not adding a toughening agent, the notch impact strength at minus 50 ℃ is more than 300J/m, and the flame-retardant grade of a sample strip with the thickness of 1.0mm reaches UL94-V0 grade, so that the high-toughness high-fluidity flame-retardant polycarbonate composition can be applied to industries with high requirements on toughness and thin-wall flame retardance, such as electronics, electrics, aerospace and the like.

Description

High-toughness and high-flow flame-retardant polycarbonate composition and preparation method and application thereof

Technical Field

The invention relates to the technical field of engineering plastics, in particular to a high-toughness flame-retardant polycarbonate composition, and a preparation method and application thereof.

Background

Polycarbonate (PC) is a general-purpose engineering plastic and has advantages of transparency, impact resistance, heat resistance, etc., wherein the halogen-free flame retardant polycarbonate composition is a material which is very widely used, but in order to meet the purpose of miniaturization, light weight, high functionality, etc. of the material in application, the polycarbonate composition should have stable thin-wall flame retardancy and ensure sufficient mechanical properties in the working and service process. However, the materials known to date do not satisfy the requirement of a thickness of 1.0mm while maintaining high toughness and flame retardancy.

Generally, the addition of the toughening agent can cause the flame retardant quality to be reduced, and the increase of the content of the flame retardant to ensure the thin-wall flame retardant can reduce the toughness of the composition, even cause the degradation of polycarbonate, and can not provide guarantee for the service safety of mechanical properties. Particularly, when the products are increasingly required to be thin-walled, the disadvantages of unstable flame retardancy, reduced toughness and reduced fluidity are large, and therefore, the above disadvantages limit the application of the materials to some extent.

Chinese patent (CN111205616A) discloses a cold-heat-resistant halogen-free flame-retardant polycarbonate alloy and a preparation method thereof, wherein polycarbonate, polysiloxane-polycarbonate, a flame retardant and an anti-dripping agent are disclosed, although the product has high impact strength at normal temperature and low temperature, the flame retardant grade is 1.6mmV-0 grade, therefore, the product prepared by the patent method can not reach the grade of 1.0mmV-0, the requirements of application context with thinner wall thickness are difficult to meet, and the product obtained by the preparation method has poor fluidity, the highest product is only 17g/10min, and the preparation method has great limitation on thin-wall products.

Disclosure of Invention

The object of the present invention is to overcome the above-mentioned drawbacks of the prior art and to provide a high-toughness, high-flowability, thin-walled, flame-retardant polycarbonate composition.

Another object of the present invention is to provide a method for preparing the high-toughness, high-fluidity, thin-walled, flame-retardant polycarbonate composition.

Another object of the present invention is to provide the use of the high toughness, high flow, thin wall flame retardant polycarbonate compositions.

The purpose of the invention is realized by the following technical scheme;

a high-toughness flame-retardant polycarbonate composition comprises the following components in parts by weight;

the low-temperature toughening stabilizer is a metal oxide subjected to hydrophobic surface treatment; the reinforcing stabilizer comprises a non-polar functionalized polyolefin.

Firstly, performing inorganic treatment on the hydrophobized surface, and coating the surface with silicon dioxide or aluminum oxide; and organic treatment, spraying nonpolar siloxane polyolefin on the surface of the metal oxide.

The weight average molecular weight of the polycarbonate is 22000-30000, the content of terminal hydroxyl is less than 100ppm, and the content of BPA is less than 50ppm, and the polycarbonate can also be prepared by a phosgene method and an ester exchange method.

The weight average molecular weight of the polycarbonate was determined using gel permeation chromatography using a crosslinked styrene-divinylbenzene column calibrated to polycarbonate standards using an ultraviolet-visible detector set at 264 nm. The sample can be prepared at a concentration of 1mg/mL and eluted at a flow rate of 1 mL/min.

The inventor utilizes the synergistic effect of polysiloxane-polycarbonate, low-temperature toughening stabilizer and reinforcing stabilizer to prepare the polycarbonate composition, which not only can ensure that the thin-wall flame retardant grade is 1.0mmV-0 grade, but also has high toughness and high fluidity.

Preferably, the composition comprises the following components in parts by weight:

preferably, the polysiloxane-polycarbonate has a weight average molecular weight of 22000-30000 and a silicon content of 6-20%.

Preferably, the average particle size of the low-temperature toughening stabilizer is 100-500 nm.

Preferably, the surface-treated metal oxide is titanium dioxide or zinc oxide.

Preferably, the nonpolar functionalized polyolefin is siloxane-based polyolefin or fluorine-containing polyolefin, and the siloxane-based polyolefin or the fluorine-containing polyolefin can cause microphase separation in a polycarbonate resin system due to the difference of compatibility, so that a certain size of gap exists in the matrix resin, and the material can generate silver streaks and shear to absorb energy under external force, thereby improving the toughness of the material; the existence of the micro-phase separation of the siloxane oxidized polyolefin or the fluorine-containing polyolefin is beneficial to preventing the crack from expanding into the defect, and the toughness can be stably improved by combining the molecular chain characteristics of Si-O and C-F.

Preferably, the flame retardant may be a sulfonate-based flame retardant, including perfluorinated C1-C16 alkyl sulfonates, such as potassium perfluorobutyl sulfonate (Rimar salt), potassium perfluorooctane sulfonate, tetraethylammonium perfluorohexane sulfonate, potassium diphenyl sulfone sulfonate (KSS), sodium benzene sulfonate, sodium toluene sulfonate (NATS).

Preferably, the flame retardant is a phosphorus-based flame retardant, an organic phosphate ester containing a phosphorus-nitrogen bond and an organic compound. The di-or polyfunctional aromatic phosphorus-containing compounds include resorcinol tetraphenyl diphosphate (RDP), the bis (diphenyl) phosphate of hydroquinone and the bis (diphenyl) phosphate of bisphenol-A, respectively; other phosphorus-containing flame retardants include phosphonitrilic chloride, phosphorus ester amides, phosphoric acid amides, phosphonic acid amides, phosphinic acid amides, tris (aziridinyl) phosphine oxide, polyorganophosphazenes, and polyorganophosphonates.

More preferably, the sulfonate ester flame retardant is potassium diphenylsulfone sulfonate.

Preferably, the anti-drip agent is at least one of a fibrillated fluoropolymer or a non-fibrillated fluoropolymer, such as Polytetrafluoroethylene (PTFE). The anti-drip agent may be encapsulated within a rigid copolymer, such as styrene-acrylonitrile copolymer (SAN). Polytetrafluoroethylene encapsulated in styrene acrylonitrile (TSAN) allows the composition to disperse more readily than neat PTFE.

The invention also provides a preparation method of the high-toughness high-fluidity flame-retardant polycarbonate composition, which comprises the following steps:

s1, respectively weighing polycarbonate, polysiloxane-polycarbonate, a flame retardant, a low-temperature toughening stabilizer, an anti-dripping agent and a reinforcing stabilizer, and sequentially putting the raw materials into a mixer to blend uniformly to obtain a premix;

s2, adding the premix prepared in the step S1 into an extruder for melt extrusion and post-processing to obtain the composition particles.

The post-processing comprises bracing, cooling, air drying and grain cutting.

The polycarbonate composition with high toughness and high fluidity and flame retardance is applied to the preparation of products in the fields of transportation, household appliances, buildings, electronic appliances or aerospace.

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

the invention provides a high-toughness flame-retardant PC composition, which is improved in toughness through the compatibility of a low-temperature toughening stabilizer and a reinforcing stabilizer, wherein the low-temperature toughening stabilizer can form good dispersion in a matrix, a gap is formed between hydrophobic property and the resin matrix to serve as rigid particles for toughening, and the synergistic reinforcing stabilizer can further enhance the dispersion of the low-temperature toughening agent, so that the defects of agglomeration and the like are avoided in the resin matrix, and the reduction of impact strength caused by the expansion of cracks of a material under the action of an external force is prevented. The PC composition has an ASTM normal temperature notched impact strength of more than 600J/m, a notched impact strength of more than 300J/m at-50 ℃, and excellent impact properties at normal temperature and low temperature. The PC composition also has excellent fluidity, the melt index of 300 ℃/1.2kg is more than 20g/10min, and the processing is easy. The flame retardant property of the flame retardant steel also has thin-wall flame retardant property under the condition of high toughness, and the flame retardant grade of a 1.0 mm-thick sample strip reaches UL94-V0 grade. Meanwhile, the polysiloxane-polycarbonate is adopted to replace the conventional toughening agent, so that the negative effects of the toughening agent on flowability, appearance and flame retardance are eliminated.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, but the embodiments of the present invention are not limited thereto.

The reagents, methods and equipment adopted by the invention are conventional in the technical field if no special description is given.

The following examples and comparative examples employ the following starting materials:

polycarbonate (C): 1300-10NP has a weight average molecular weight of 22000-30000 and a terminal hydroxyl content of less than 100ppmLG

Polysiloxane-polycarbonate: d-13 weight-average molecular weight of 22000-30000 and silicon content of 6-20 percent, and the novel color-changing material

Titanium dioxide: r104 DuPont

Titanium dioxide: s-100 southern China university of science

Titanium dioxide: s-500 south China university of science

Titanium dioxide: s-700 south China university of science

Hydrophobized titanium dioxide A: r104 hydrophobicized titanium dioxide obtained by surface treatment of titanium dioxide with a siliconized polyolefin by air-blowing, the average particle size of the hydrophobicized R104 obtained

Hydrophobized titanium dioxide B: s-100 hydrophobized titanium dioxide obtained by surface treatment of titanium dioxide with a siliconized polyolefin by air-blowing, the hydrophobized S-100 thus obtained having an average particle size of 100nm

Hydrophobized titanium dioxide C: s-500 hydrophobicized titanium dioxide obtained by surface treatment of titanium dioxide with a siliconised polyolefin by air-blowing, the hydrophobicized S-500 thus obtained having an average particle size of 500nm

Hydrophobized titanium dioxide D: s-700 hydrophobicized titanium dioxide obtained by surface treatment of titanium dioxide with a siliconized polyolefin by means of air-blowing, the average particle size of the hydrophobicized S-700 obtained being 700nm

Zinc oxide: zinc oxide Aladdin Co

Hydrophobized surface-treated zinc oxide: firstly, carrying out inorganic treatment, and coating the surface with silicon dioxide or aluminum oxide; performing organic treatment, spraying nonpolar siloxane polyolefin on the surface of zinc oxide, and making the hydrophobic zinc oxide have average particle diameter of 200nm

Reinforcing and stabilizing agent: siliconized polyolefins S10 Osaka Japan gas

Anti-dripping agent: AS-coated PTFE POLYTE30X Korean Pacific ocean

Flame retardant: sodium benzenesulfonate HES American Arichem

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

The following examples and comparative examples each prepared a polycarbonate composition by weighing the components in the weight ratios shown in tables 1 to 5; the method comprises the following specific steps:

s1, respectively weighing polycarbonate, polysiloxane-polycarbonate, a wet heat stabilizer, a low-temperature toughening stabilizer and an anti-dripping agent, and then putting the raw materials into a mixer with a preset temperature of 50 ℃ and a rotation speed of 200rpm to blend uniformly to obtain a premix;

s2, adding the premix prepared in the step S1 into an extruder with the preset temperature of 230-260 ℃ and the main machine rotation speed of 450rpm for melt extrusion, bracing, cooling, air drying and granulating to obtain the composition particles.

TABLE 1 examples 1-7 component content

Table 2 examples-12 component contents

Components (parts)	Example 8	Example 9	Example 10	Example 11	Example 12
						Polycarbonate resin	70	70	70	70	70
Polysiloxane-polycarbonates	0.01	0.1	1	10	20
						Hydrophobized titanium dioxide A	0.2	0.2	0.2	0.2	0.2
Reinforcing stabilizer	0.3	0.3	0.3	0.3	0.3
						Anti-dripping agent	0.5	0.5	0.5	0.5	0.5
Flame retardant	0.3	0.3	0.3	0.3	0.3

TABLE 3 examples 13-18 component content

TABLE 4 examples 19 to 27 component content

TABLE 5 comparative examples 1-5 component content

Components (parts)	Comparative example 1	Comparative example 2	Comparative example 3	Comparative example 4	Comparative example 5
						Polycarbonate resin	70	70	70	70	70
Polysiloxane-polycarbonates	—	30	—	30	30
						Titanium dioxide	—	—	—	0.2(R104)	—
Hydrophobized titanium dioxide A	—	—	0.2	—	0.2
						Reinforcing stabilizer	0.3	—	—	0.3	5
Anti-dripping agent	0.5	0.5	0.5	0.5	0.5
						Flame retardant	2	0.3	0.3	0.3	0.3

The high toughness flame retardant polycarbonate compositions prepared in examples 1 to 27 and comparative examples 1 to 5 above were subjected to the following performance tests according to the following standards and methods:

method for determining melt flow rate: selecting a test condition of 1.2kg load on a melt index instrument with a set temperature of 300 ℃ according to ISO1133-2011 standard, weighing the set weight of the particles to be tested, testing the melt index within a retention time of 240s, and recording data to calculate the melt index MI of the material.

UL94 flame retardancy test method: the flammability test was carried out according to the protocol "flammability test of plastic materials, UL 94". The flame rating is derived based on the burn rate, the extinguishing time, the ability to resist droops, and whether the droops are burning. Samples used for the test: 125mm length 13mm width, the thickness of the invention when tested is selected to be 1.0mm, and the flame retardant rating of the material can be classified as (UL94-HB) according to the UL94 protocol: v0, V1, V2, 5VA and/or 5 VB.

Determination of ASTM notched impact Strength: testing 3.0mm IZOD notched impact strength according to ASTM D256-2010; the notch type is an injection molded notch, wherein the higher the impact strength, the better the material toughness. -50 ℃ impact strength is also 3.0mm IZOD notched impact strength measured according to ASTM D256; the notch type is an injection molding notch, the sample strip is placed into a freezer at the temperature of 50 ℃ below zero and is adjusted for more than 4 hours, then the sample strip is taken out for testing, and the obtained test result is low-temperature impact strength, wherein the higher the impact strength is, the better the low-temperature toughness of the material is.

The physical properties and flame retardant property test results of the high toughness flame retardant polycarbonate compositions of examples 1-27 and comparative examples 1-5 are shown in Table 6.

Table 6 results of performance testing

In examples 1 to 6, the fluidity was slightly decreased due to the increase of the force acting between the PC molecular chains, and the impact at normal temperature was maintained at the same level, but the impact strength at low temperature was slightly decreased due to the decrease of the content of the silicon copolymer component as a whole, the dispersion uniformity of the components was decreased, and the decrease was not large and the flame retardant rating was not changed due to the presence of the low temperature toughening agent and the reinforcing agent.

The higher the polysiloxane-polycarbonate content in examples 8-12, the higher the low temperature notched impact strength. As the content of the polysiloxane-polycarbonate copolymer increases, the melt index increases because the presence of the copolymerized silicon component reduces entanglement among PC molecular chains, and because the presence of a certain content of siloxane improves the processing fluidity of the composition, the low-temperature impact is obviously improved and the flame retardant grade is maintained unchanged as the content increases.

In examples 13 to 18, the fluidity decreased with the increase in the content of the low-temperature toughening agent, and the change in the normal-temperature impact and the low-temperature impact increased with the increase in the amount of the reinforcing stabilizer, but the low-temperature toughening agent tended to decrease after increasing to the optimum value because the effective distance between the resin layers existed after the uniform dispersion of the low-temperature toughening agent in the system, and the distance between the resin layers decreased with the increase in the amount of the reinforcing stabilizer, and the toughness was adversely affected after decreasing to a certain extent.

In examples 19 to 24, the fluidity increased with the increase of the reinforcing stabilizer, the room-temperature notched impact strength slightly increased in the presence of the low-temperature toughening stabilizer, and the low-temperature notched impact strength increased with the addition amount and the fluidity also increased. The low-temperature toughening stabilizer in a certain particle size range can form good dispersion in a matrix, a certain gap is formed between the hydrophobization and the resin matrix to serve as rigid particles for toughening, and the synergistic enhancement stabilizer can further enhance the dispersion of the low-temperature toughening agent, so that no defect points such as agglomeration and the like occur in the resin matrix, and the reduction of impact strength caused by the expansion of cracks of the material under the action of external force is prevented.

From examples 4 and 25 to 27, it can be seen that the use of hydrophobicized titanium dioxide of different particle sizes has an effect on the data of polycarbonate, wherein the room-temperature impact strength and the low-temperature impact strength increase and then decrease when the particle size increases from 100nm to 500nm, and both the room-temperature impact strength and the low-temperature impact strength are smaller than those of the hydrophobicized titanium dioxide of particle size of between 100 and 500nm when the particle size is 700 nm.

Comparative examples 1-5 did not achieve thin wall flame retardance, ASTM notched impact strength at normal temperature greater than 600J/m, and notched impact strength at-50 ℃ greater than 300J/m.

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 (7)

1. The high-toughness high-fluidity flame-retardant polycarbonate composition is characterized by comprising the following components in parts by weight:

the low-temperature toughening stabilizer is a metal oxide subjected to hydrophobic surface treatment; the reinforcing stabilizer is siloxane-based polyolefin;

firstly, performing inorganic treatment on the hydrophobized surface, and coating the surface with silicon dioxide or aluminum oxide; then organic treatment is carried out, and nonpolar siloxane polyolefin is sprayed on the surface of the metal oxide;

the metal oxide is titanium dioxide or zinc oxide; the average particle size of the low-temperature toughening stabilizer is 100-500 nm.

2. The high toughness, high flow flame retardant polycarbonate composition of claim 1, wherein the polysiloxane-polycarbonate has a weight average molecular weight of 22000-30000 and a silicon content of 6-20%.

3. The high toughness, high flow flame retardant polycarbonate composition of claim 1, wherein the flame retardant is one of a sulfonate flame retardant or a phosphorus flame retardant.

4. The high toughness, high flow flame retardant polycarbonate composition of claim 3, wherein the sulfonate-based flame retardant is potassium diphenylsulfone sulfonate.

5. The high toughness, high flow flame retardant polycarbonate composition of claim 1, wherein the anti-drip agent is one of a fibrillated fluoropolymer or a non-fibrillated fluoropolymer.

6. The method of preparing the high toughness, high flow flame retardant polycarbonate composition of any of claims 1-5, comprising the steps of:

s1, respectively weighing polycarbonate, polysiloxane-polycarbonate, a flame retardant, a low-temperature toughening stabilizer, an anti-dripping agent and a reinforcing stabilizer, and sequentially putting the raw materials into a mixer to blend uniformly to obtain a premix;

s2, adding the premix prepared in the step S1 into an extruder for melt extrusion and post-processing to obtain the composition particles.

7. Use of the high toughness, high flow flame retardant polycarbonate composition of any of claims 1-5 in the manufacture of an article for transportation, household appliance, building material, electronic appliance, or aerospace.