Novel anti-dripping agent and application thereof in fluoride-free flame-retardant PC product

Abstract

The invention discloses a preparation method of a novel anti-dripping agent and application of the novel anti-dripping agent in a fluoride-free flame-retardant PC (polycarbonate) product, silica gel microspheres are infiltrated in an organic solution of polycarbonate to form'hedgehog-like 'particles, and a certain anti-dripping effect is achieved through winding connection between an apparent overhanging molecular chain and a matrix. Meanwhile, the invention further provides a completely fluorine-free flame-retardant PC product which comprises polycarbonate, a flame retardant, a novel anti-dripping agent, an antioxidant, a lubricant, a flexibilizer and an optional silicon synergist, the same effect of PTFE can be achieved through the novel anti-dripping agent and the optional silicon synergist, V0 flame retardance of the product is achieved, and the completely fluorine-free flame-retardant PC product is widely applied to the fields of electronics and the like.

Description

Technical Field

[0001] This invention relates to the field of polymer materials, and more particularly to a novel anti-dripping agent and its application in fluorine-free flame-retardant PC products. Background Technology

[0002] There are currently over 12,000 perfluorinated and polyfluoroalkyl substances (PFAS), which are widely used in the chemical, coating, textile, and food contact industries due to their good chemical stability and high surface activity. However, PFAS are fluorine-containing substances, and once they enter the environment and the bodies of animals and plants, they will cause irreversible damage. Currently, many regions and industries have introduced regulations restricting or prohibiting the use of certain PFAS substances. For example, DIN / VDE 0472 Part 815 (Inspection of cables and insulated conductors: Verification of halogen-free compounds) stipulates that the permissible fluorine content is limited to less than or equal to 0.1 wt%. On February 7, 2023, the European Chemicals Agency (ECHA) published a joint proposal from Denmark, Germany, the Netherlands, Norway, and Sweden to restrict the use of perfluorinated and polyfluoroalkyl substances (PFAS) under the REACH regulation, planning to comprehensively restrict the use of PFAS substances. Therefore, the restriction and prohibition of fluorine is an inevitable trend. However, polytetrafluoroethylene (PTFE) has long been used as an anti-dripping agent in flame-retardant PC and other products, so the development of alternative products has become urgent.

[0003] In the prior art, CN1300308A discloses a method for preparing a flame retardant composition with a fluorine content of no more than 0.1 wt%. However, in these compositions, although the fluorine content is no more than 0.1 wt%, a higher content of phosphorus-containing flame retardant is used, which leads to a decrease in the heat resistance of the composition, such as the Vicat softening temperature.

[0004] CN101104730B discloses a method for preparing a flame-retardant composition with a fluorine content of no more than 0.1 wt%. By adding silica and epoxy resin, it maintains good anti-dripping properties without significantly reducing heat resistance. However, the addition of silica significantly affects the product appearance, so it is not suitable for all systems, and the composition still retains a certain amount of fluorine.

[0005] CN117327382A discloses a fluorine-free flame-retardant PC product that uses silicon nanotubes to replace traditional anti-dripping agents; however, in practice, the anti-dripping effect of silicon nanotubes during secondary combustion is very poor and cannot reach the effect of PTFE, especially in high-flow systems, so it has no practical application value.

[0006] CN103339198A discloses a fluorine-free flame-retardant PC and alloy products, which uses a combination of high-surface-area inorganic forged silica and a small amount of high-viscosity dimethyl organosilicon and inorganic fillers such as talc powder, which can achieve a flame-retardant effect of V0 at high thickness, but the thickness is too thick and there are few application scenarios.

[0007] CN104364313A discloses a fluorine-free flame-retardant PCGF reinforcing material, which obtains a fluorine-free flame-retardant system by using phosphazene flame retardants, glass fibers, etc., but the presence of glass fibers limits its application in smooth parts.

[0008] Therefore, existing technologies all have their own limitations and cannot completely replace PTFE while retaining its original characteristics, thus losing their application in many fields. Summary of the Invention

[0009] To address the shortcomings of the existing technology, this invention provides a novel anti-dripping agent and its application in fluorine-free flame-retardant PC products.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] In a first aspect, this invention provides a novel anti-dripping agent comprising silica microspheres and polycarbonate (PC). The preparation method of this novel anti-dripping agent is as follows:

[0012] An organic solution of polycarbonate is prepared, and then silica microspheres are added and stirred to dissolve and impregnate the solution. The stirring speed is 100-400 rpm and the time is 30-60 min. After the stirring is completed, the organic solvent is removed by flash evaporation. The final powder is the novel anti-dripping agent.

[0013] In the preparation method of the novel anti-dripping agent of the present invention, the polycarbonate is an aromatic polycarbonate, preferably bisphenol A type polycarbonate; preferably, under test conditions of 300°C and 1.2 kg, the melt flow index of the polycarbonate is 1-7 g / 10 min, more preferably 1-5 g / 10 min; preferably, the viscosity-average molecular weight of the polycarbonate is between 20,000 and 40,000, such as Wanhua 2030PC resin and Wanhua 2070PC resin.

[0014] In the preparation method of the anti-dripping agent of the present invention, the organic solvent can be selected from one or more of dichloromethane, chloroform, carbon tetrachloride, etc.; the silica microspheres have a particle size of 3000-10000 mesh, preferably 5000-10000 mesh, and a specific surface area of ​​300-600 m². 2 / g, at this point the silica gel particle size is small, so it will not become a stress defect point, and the number of new anti-drip particles can be increased, which is conducive to improving the anti-drip effect.

[0015] In the preparation method of the anti-dripping agent of the present invention, the mass ratio of polycarbonate to silica microspheres is (5-10):(3-6).

[0016] In this invention, the flash evaporation is used to remove the organic solvent. The flash evaporation conditions can be adjusted conventionally as long as the purpose of removing the organic solvent is achieved. For example, the flash evaporation temperature can be 10-35℃ and the pressure can be 0.1-1 atm.

[0017] A second aspect of the present invention also provides a fluorine-free flame-retardant PC product, wherein the fluorine-free flame-retardant PC product comprises the above-mentioned novel anti-dripping agent, specifically, the fluorine-free flame-retardant PC product comprises the following components:

[0018] Polycarbonate 90-98%,

[0019] Flame retardant 0.1-4%,

[0020] New anti-dripping agent 0.3-2.5%,

[0021] Antioxidant 0.1-0.4%,

[0022] Lubricant 0.3-0.8%,

[0023] Toughening agent 0.5-3%,

[0024] Silicon synergist 0-2%.

[0025] The polycarbonate in the fluorine-free flame-retardant PC product of the present invention is an aromatic polycarbonate, preferably bisphenol A type polycarbonate; preferably, under test conditions of 300°C and 1.2 kg, the melt flow index of the polycarbonate is 3-35 g / 10 min, more preferably 10-20 g / 10 min; even more preferably, Wanhua Chemical's CLARNATE series products, etc.

[0026] The flame retardant in the fluorine-free flame-retardant PC product of the present invention can be selected from one or more halogen-free environmentally friendly systems such as sulfonate flame retardants and P-series flame retardants; preferably, the sulfonate flame retardant can be selected from flame retardants of systems such as KSS and HES, and the P-series flame retardant can be selected from flame retardants of flame retardant systems such as BDP, RDP, and phosphazene.

[0027] The antioxidant in the fluorine-free flame-retardant PC product of the present invention is one or more of the following: hindered phenols, phosphites, thioesters, benzofurans, acryloyl-modified phenols, and hydroxylamine antioxidants.

[0028] The lubricant in the fluorine-free flame-retardant PC product of the present invention is one or more of the following: fatty alcohols, metal soaps, fatty acids, fatty acid esters, lignite acid and its derivatives, amide waxes, saturated hydrocarbons, polyolefin waxes and their derivatives, organosilicon and silicone powders, and organofluorine compounds.

[0029] The toughening agent in the fluorine-free flame-retardant PC product of the present invention includes one or more of EMA, MBS, and silicone-based toughening agents.

[0030] The silicon synergist in the fluorine-free flame-retardant PC product of the present invention is an inorganic silicon synergist, preferably one or more of silica, wollastonite, silicate, glass fiber, etc., and more preferably Tosla's Fireproof Sil-1.

[0031] Other additives may be added to the fluorine-free flame-retardant PC product of the present invention, such as compatibilizers, ultraviolet absorbers, infrared absorbers, heat stabilizers, metal passivators, colorants, coupling agents, foaming agents, hydrolysis resistant agents, chain extenders, flow modifiers, matting agents, antistatic agents, reinforcing agents, fillers, light diffusing agents, metallic pigments, and pearlescent powders in one or more combinations thereof; the amount of other additives added can be adjusted by those skilled in the art according to different application scenarios.

[0032] The third aspect of this invention provides a method for preparing the above-mentioned fluorine-free flame-retardant PC product, comprising the following steps: adding polycarbonate, flame retardant, novel anti-dripping agent, toughening agent, antioxidant, lubricant, optional silicone synergist and optional other additives to a mixer in proportion and mixing for 3-30 minutes to obtain a mixed raw material; extruding the mixed raw material through a twin-screw extruder, granulating and drying.

[0033] In the method for preparing fluorine-free flame-retardant PC products described in this invention, the temperature of the melting section during twin-screw extrusion is 265-275℃, the temperature of the mixing section is 270-285℃, and the temperature of the extrusion section is 270-280℃.

[0034] The fluorine-free flame-retardant PC product described in this invention can be widely used in the fields of electronics and electrical appliances.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] This invention utilizes silica microspheres as a carrier to adsorb and store PC. Under continuous stirring, a novel anti-dripping agent with a "hedgehog-like" structure is formed, centered on the microspheres and with PC chain segments embedded within the pores. The anti-dripping effect is achieved by the apparent entanglement of the PC long molecular chains derived from this anti-dripping agent with the PC matrix. The addition of a silica synergist further improves the anti-dripping effect. The fluorine-free flame-retardant PC product of this invention achieves a 1.5mm V0 flame retardant rating, a melt flow index (MI) in the range of 10-20 g / 10 min (300℃ / 1.2 kg), and a room-temperature notched impact strength maintained at 40-50 kJ / m². 2 (ISO180) ultimately achieved the same flame retardant effect as PTFE and was completely fluorine-free, which is in line with future development trends. Detailed Implementation

[0037] The following examples further illustrate preferred embodiments within the scope of the present invention. The raw materials used in the examples and comparative examples are described below:

[0038] 2030: Bisphenol A type polycarbonate produced by the interfacial phosgene method, with a melt flow index of [missing value].

[0039] 2.5g / 10min (300℃, 1.2kg), viscosity-average molecular weight 31000, produced by Wanhua Chemical Group Co., Ltd.

[0040] 2070: Bisphenol A type polycarbonate produced by interfacial phosgene method, with a melt flow index of 6.5 g / 10 min (300℃, 1.2 kg) and a viscosity-average molecular weight of 26,000, produced by Wanhua Chemical Group Co., Ltd.

[0041] 2100: Bisphenol A type polycarbonate produced by interfacial phosgene method, with a melt flow index of 9 g / 10 min (300℃, 1.2 kg), produced by Wanhua Chemical Group Co., Ltd.

[0042] 2220: Bisphenol A type polycarbonate produced by interfacial phosgene method, with a melt flow index of 20 g / 10 min (300℃, 1.2 kg), produced by Wanhua Chemical Group Co., Ltd.

[0043] PETS: Pentaerythritol stearate, a lubricant, produced by Dirun Chemical.

[0044] B900: Antioxidant, manufactured by BASF;

[0045] Flame retardants: KSS, HES, produced by Arichem;

[0046] Phosphazene flame retardant: manufactured by Fuji Electric Corporation of Japan, FP-110;

[0047] BDP: BDP-600, flame retardant, manufactured by Adico;

[0048] Toughening agent: M505, manufactured by Formosa Plastics;

[0049] Silicone synergist: Fireproof Sil-1, manufactured by Tolsa.

[0050] Silica microspheres A: Particle size 8000 mesh, specific surface area 600 m² 2 / g, Shaanxi Shengrui Pharmaceutical Technology Co., Ltd.;

[0051] Silica microspheres B: Particle size 5000 mesh, specific surface area 500 m² 2 / g, Shaanxi Shengrui Pharmaceutical Technology Co., Ltd.;

[0052] Silica microspheres C: Particle size 3000 mesh, specific surface area 300 m² 2 / g, Shaanxi Shengrui Pharmaceutical Technology Co., Ltd.;

[0053] Anti-dripping agent: FD3100, a fluorinated anti-dripping agent, produced by Luju Chemical;

[0054] Melt flow index was tested according to ISO 1133 standard, under conditions of 300℃ / 1.2kg;

[0055] Impact performance was tested according to ISO 180 standard;

[0056] Flame retardant performance is tested according to UL94 standard;

[0057] Example 1

[0058] The novel anti-dripping agent A is prepared as follows:

[0059] 500g of PC2030 was dissolved in dichloromethane, and then 300g of silica microspheres A were added to the solution and stirred, dissolved and wetted at 200 rpm for about 40 minutes. After the process, the dichloromethane solvent was directly volatilized in a flash evaporator (temperature 23℃, pressure 0.2 atm). The resulting powder is the new anti-dripping agent A.

[0060] Example 2

[0061] The novel anti-dripping agent B is prepared as follows:

[0062] 1000g of PC2030 was dissolved in chloroform, and then 600g of silica microspheres C were added to the solution and stirred, dissolved and wetted at 400rpm for about 60min. After the reaction, the solvent chloroform was directly volatilized in a flash evaporator (temperature 35℃, pressure 0.5atm). The final powder was the new anti-dripping agent B.

[0063] Example 3

[0064] The novel anti-dripping agent C is prepared as follows:

[0065] 800g of PC2070 was dissolved in carbon tetrachloride, and then 500g of silica microspheres B were added to the solution and stirred, dissolved and wetted at 300 rpm for about 50 minutes. After the process, the solvent carbon tetrachloride was directly volatilized in a flash evaporator (temperature 30℃, pressure 0.2 atm). The final powder was the new anti-dripping agent C.

[0066] Examples 4-10 are the prepared fluorine-free flame-retardant PC products. Specific components and performance tests are shown in Table 1. Comparative Examples 1-5 and their performance tests are shown in Table 2.

[0067] Table 1. Raw material composition and performance tests of the fluorine-free flame-retardant PC products in Examples 4-10

[0068]

[0069] Table 2 Comparative Examples 1-5: Raw Material Composition and Performance Tests

[0070]

[0071]

[0072] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A novel anti-dripping agent comprising silica microspheres and polycarbonate, the preparation method of which is as follows: Polycarbonate was dissolved in an organic solvent, then silica microspheres were added for impregnation, and then the organic solvent was removed to obtain a novel anti-dripping agent.

2. The novel anti-dripping agent according to claim 1, characterized in that, The polycarbonate is an aromatic polycarbonate, preferably a bisphenol A type polycarbonate; preferably, under test conditions of 300°C and 1.2 kg, the melt flow index of the polycarbonate is 1-7 g / 10 min, more preferably 1-5 g / 10 min.

3. The novel anti-dripping agent according to claim 1, characterized in that, The specific surface area of ​​the silica microspheres described in this invention is 300-600 m². 2 / g, with a particle size of 3000-10000 mesh, preferably 5000-10000 mesh.

4. The novel anti-dripping agent according to any one of claims 1-3, characterized in that, The mass ratio of polycarbonate to silica microspheres is (5-10):(3-6).

5. The novel anti-dripping agent according to claim 1, characterized in that, The organic solvent is one or more of dichloromethane, chloroform, and carbon tetrachloride.

6. The novel anti-dripping agent according to claim 1, characterized in that, The soaking time is 30-60 min; and / or, stirring is performed during soaking at a speed of 100-400 rpm.

7. A fluorine-free flame-retardant PC product comprising the novel anti-dripping agent as described in any one of claims 1-6, characterized in that, It contains the following components: Polycarbonate 90-98%, Flame retardant 0.1-4%, New anti-dripping agent 0.3-2.5%, Antioxidant 0.1-0.4%, Lubricant 0.3-0.8%, Toughening agent 0.5-3%, Silicon synergist 0-2%.

8. The fluorine-free flame-retardant PC product according to claim 7, characterized in that, The polycarbonate in the fluorine-free flame-retardant PC product is an aromatic polycarbonate, preferably bisphenol A type polycarbonate; preferably, under test conditions of 300°C and 1.2 kg, the melt flow index of the polycarbonate is 3-35 g / 10 min, more preferably 10-20 g / 10 min.

9. The fluorine-free flame-retardant PC product according to claim 7 or 8, characterized in that, The flame retardant is selected from sulfonate flame retardants and P-based flame retardants; preferably, the sulfonate flame retardant is selected from KSS and HES systems, and preferably, the P-based flame retardant is selected from BDP, RDP, and phosphazene systems; and / or: the silicon synergist is an inorganic silicon synergist.

10. A method for preparing a fluorine-free flame-retardant PC product according to any one of claims 7-9, characterized in that, The process includes the following steps: mixing polycarbonate, flame retardant, novel anti-dripping agent, antioxidant, lubricant, toughening agent and optional silicone synergist, extruding, granulating and drying; preferably, the temperature of the melting section during the extrusion process is 265-275°C, the temperature of the mixing section is 270-285°C, and the temperature of the extrusion section is 270-280°C.

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