A polycarbonate composition with high mid-infrared reflection

Abstract

The invention relates to a polycarbonate composition with high mid-infrared reflection. The components of the polycarbonate composition include, by weight: 70-85 parts of PC resin; 10-16 parts of titanium dioxide; 0.1-1 parts of black pigment; and 2-5 parts of toughening agent. The polycarbonate composition has high mid-infrared reflection and good toughness.

Description

Technical Field

[0001] The invention belongs to the technical field of engineering plastic modification, and particularly relates to a polycarbonate composition with high mid-infrared reflection. Background Art

[0002] Infrared is one of the many invisible rays in sunlight. The wavelength of infrared is longer than that of visible light, and the wavelength range is 0.75μm-1000μm. According to the length of the wavelength, it is divided into near-infrared, mid-infrared and far-infrared parts. Among them, the 2-5μm mid-infrared band includes multiple high-transmittance atmospheric windows and characteristic absorption bands of many molecules. At the same time, it is in the peak range of thermal radiation of high-temperature objects of 300-1000℃. Therefore, laser light sources in this band can be used in military and civilian fields such as infrared countermeasures, air defense warning, laser communication and ranging, atmospheric environment monitoring, material processing and biomedicine. In lasers, sensors and other equipment, parts are usually required to have high reflectivity to mid-infrared to facilitate signal transmission and instrument design.

[0003] PC is usually used in built-in components or casings of equipment such as lasers due to its high heat resistance and mechanical properties. When used in built-in components, it has extremely low mid-infrared reflectivity. Therefore, the conventional practice is to sputter a metal film on the surface to enhance mid-infrared reflection, which is expensive and inconvenient to operate.

[0004] At present, the research on light-reflective PC is focused on the reflection of visible light. For example, Chinese patents CN104220502A, CN106995600A and CN105968771A all announced the preparation of high-reflectivity PC. The technology mainly focuses on the content and use of conventional titanium dioxide, which is applied to products such as lighting lampshades. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a polycarbonate composition with high mid-infrared reflection, which can overcome the defect of low mid-infrared reflection of polycarbonate in the prior art and avoid secondary metal film sputtering treatment.

[0006] The present invention provides a polycarbonate composition with high mid-infrared reflection, wherein the components of the polycarbonate composition include, by weight:

[0007]

[0008] The titanium dioxide particle size D50 and its distribution by weight percentage include:

[0009] 2.4μm≤D50≤2.6μm 20%-30%;

[0010] 0.6μm≤D50≤1.3μm 40%-50%;

[0011] 0.15μm≤D50≤0.3μm 20%-40%;

[0012] The toughening agent is ethylene-glycidyl ester copolymer.

[0013] The characterization method of titanium dioxide particle size D50 and its distribution is as follows: take the polycarbonate composition obtained by a twin-screw extruder, refer to ISO 3451.1-2019, and obtain the ash content of the composition; put 0.2g of the sample into 150ml of 0.3% sodium pyrophosphate aqueous solution, stir in a magnetic stirrer at 700r / min for 2min and then test. The D50 particle size and its distribution are measured by laser method, referring to GB / T19077.1-2008 particle size analysis laser diffraction method.

[0014] Preferably, the polycarbonate composition comprises the following components in parts by weight:

[0015]

[0016] Preferably, the PC resin is aromatic polycarbonate.

[0017] Preferably, the PC resin has a viscosity average molecular weight of 18,000 to 25,000.

[0018] Preferably, the black pigment is a metal oxide black pigment.

[0019] More preferably, the metal oxide black pigment includes one or more of iron / chromium oxide, calcium / titanium / manganese oxide, and copper / chromium oxide.

[0020] Preferably, the black pigment has an oil absorption of 12-18 g / 100 g. The test standard for the oil absorption is ISO787 / 5-1980 "General Test Methods for Pigments and Extenders - Part 5: Determination of Oil Absorption", in which refined linseed oil is used as the test oil. Black pigments within this oil absorption value range have good resistance to color penetration and do not affect the light reflection effect of titanium dioxide.

[0021] Preferably, the ethylene-glycidyl ester copolymer comprises an ethylene-based copolymer grafted with glycidyl methacrylate; and / or a random terpolymer of ethylene, acrylate and glycidyl methacrylate.

[0022] More preferably, the ethylene-glycidyl ester copolymer is a random terpolymer of ethylene-based copolymer grafted with glycidyl methacrylate and ethylene, acrylate and glycidyl methacrylate in a weight ratio of 1.5:1-1:1.5.

[0023] Preferably, the polycarbonate composition further comprises 0-1 part of other additives.

[0024] Preferably, the other auxiliary agents include lubricants and / or antioxidants.

[0025] Preferably, the lubricant is present in an amount of 0.1-0.3 parts by weight.

[0026] Preferably, the lubricant includes one or more of pentaerythritol tetrastearate, glycerol monostearate, and glycerol tristearate.

[0027] Preferably, the antioxidant is present in an amount of 0.01-0.3 parts by weight.

[0028] Preferably, the antioxidant includes one or more of hindered phenol antioxidants, phosphite antioxidants, and propionate antioxidants.

[0029] The present invention also provides a method for preparing a polycarbonate composition with high mid-infrared reflection, comprising:

[0030] The components are mixed, and the obtained premix is ​​put into a twin-screw extruder, melt-mixed, extruded and granulated to obtain a polycarbonate composition with high mid-infrared reflection.

[0031] Preferably, the twin-screw extruder has a melt mixing temperature of 240-260° C., a screw length-to-diameter ratio of 40:1-48:1, and a screw speed of 400-500 rpm.

[0032] The present invention also provides an application of a polycarbonate composition with high mid-infrared reflection in mid-infrared application equipment, such as lasers, sensors or medical devices.

[0033] Titanium dioxide is a commonly used inorganic reflective particle with a high refractive index and good hiding power. The higher the refractive index, the higher the reflectivity. When light is incident, the inorganic reflective particles with a particle size smaller than half the wavelength of the incident light will diffract. The mid-infrared wavelength is 2-5 μm, and it has extremely high diffraction properties for inorganic reflective particles of conventional particle sizes. When the present invention uses titanium dioxide particle size D50 2.4-2.6 μm with a weight percentage of 20%-30%, particle size D50 0.6 μm-1.3 μm with a weight percentage of 40-50%, and particle size D50 0.15 μm-0.3 μm with a weight percentage of 20-40%, the diffraction of the mid-infrared is reduced as much as possible. The compounding of different particle sizes achieves the maximum refraction of mid-infrared rays of different mid-wavelengths and improves the reflectivity of the mid-infrared.

[0034] The ethylene-glycidyl ester copolymer used in the present invention contains ethylene elastomer, which plays a connecting and buffering role between the components, so that when the system is impacted, it can disperse and buffer the impact energy, reduce the chance of silver streaks developing into cracks due to stress, and thus improve the toughness of the composition.

[0035] Beneficial Effects

[0036] The present invention adopts a specific titanium dioxide particle size distribution to improve the mid-infrared reflection of the polycarbonate composition. Since titanium dioxide deteriorates the toughness, the present invention adopts ethylene-glycidyl ester copolymer as a toughening agent to ensure the toughness of the polycarbonate composition. The polycarbonate composition has a mid-infrared (wavelength 2-5 μm) reflectivity greater than 70%, such as 71.2%-78.1%, and a notched cantilever beam impact strength greater than 500 J / m, such as 501-653 J / m. DETAILED DESCRIPTION

[0037] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0038] Source of reagents:

[0039] PC resin 1: aromatic polycarbonate, viscosity average molecular weight 20000, PC H-3000, Mitsubishi, Japan;

[0040] PC resin 2: aromatic polycarbonate, viscosity average molecular weight 24000, PC S-2000F, Mitsubishi, Japan;

[0041] PC resin 3: aromatic polycarbonate, viscosity average molecular weight 16000, PC H-4000F, Mitsubishi, Japan;

[0042] PC resin 4: aromatic polycarbonate, viscosity average molecular weight 28000, PC E-2000F, Mitsubishi, Japan;

[0043] Particle size D50 2.4μm-2.6μm Titanium dioxide: TIPAQUE PFR404, Ishihara, Japan;

[0044] Particle size D50 0.6μm-1.3μm Titanium dioxide: IR-1000, Shandong Dongjia;

[0045] Particle size D50 0.15μm-0.3μm Titanium dioxide: 2233, Konnos, Germany;

[0046] Particle size D50 0.05-0.1μm titanium dioxide: CQ-907, Dongguan Longchuang;

[0047] Titanium dioxide 1, titanium dioxide 2, titanium dioxide 3, and titanium dioxide 4 in the following table are composed of different contents of titanium dioxide TIPAQUE PFR404, IR-1000, 2233, and CQ-907, respectively.

[0048] Black pigment 1: calcium / titanium / manganese oxide, TIPAQUE BLACK SG-103, Ishihara, Japan, oil absorption is 13g / 100g; Black pigment 2: iron / chromium oxide, Sicopal Black K 0095, BASF, Germany, oil absorption is 16g / 100g;

[0049] Black Pigment 3: Iron / Chromium Oxide, A2901, Giant Hair Pigment, Oil Absorption 11g / 100g;

[0050] Black pigment 4: iron / chromium oxide, HS-2902, Huashan High-tech Ceramics, oil absorption is 19g / 100g;

[0051] Toughener 1: Ethylene copolymer grafted with glycidyl methacrylate, SOG-02, Jiayirong;

[0052] Toughener 2: random terpolymer of ethylene, acrylate and glycidyl methacrylate, KT-22, Shenyang Ketong; Toughener 3: styrene-butadiene-glycidyl ester copolymer, SBG-01, Jiayirong;

[0053] Other additives:

[0054] Lubricant: pentaerythritol tetrastearate, commercially available;

[0055] Antioxidant: Hindered phenol antioxidant, β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, commercially available; unless otherwise specified, a component (such as lubricant, antioxidant) in the parallel embodiments and comparative examples of the present invention are the same commercially available products.

[0056] The preparation method of the polycarbonate composition comprises: mixing the components according to the proportions in Table 1, Table 2 and Table 3, feeding the obtained premix into a twin-screw extruder, melt mixing, extruding and granulating, wherein the melt mixing temperature of the twin-screw extruder is 240-260° C., the screw aspect ratio is 45:1, and the screw speed is 400-500 rpm.

[0057] The characterization method of titanium dioxide particle size D50 and its distribution is as follows: take the polycarbonate composition obtained by a twin-screw extruder, refer to ISO 3451.1-2019, and obtain the ash content of the composition; put 0.2g of the sample into 150ml of 0.3% sodium pyrophosphate aqueous solution, stir in a magnetic stirrer at 700r / min for 2min and then test. The D50 particle size and its distribution are measured by laser method, referring to GB / T19077.1-2008 particle size analysis laser diffraction method.

[0058] Performance Test:

[0059] (1) Mid-infrared reflectivity: A 160T injection molding machine was used to prepare the product, with an injection temperature of 300°C and an injection speed of 80 mm / s to mold a 100 mm*100 mm*2 mm square plate. The prepared square plate was tested for reflectivity at 2000-3300 nm using a Hitachi 4100 spectrophotometer, and the reflectivity at 2500 nm, i.e., 2.5 μm, was used to represent the mid-infrared reflectivity of the present invention;

[0060] (2) Toughness: expressed as notched Izod impact strength, measured at 23° C. using a 3.2 mm thick molded notched Izod impact bar according to ASTM D256-2010.

[0061] Table 1 Example 1-9 Proportions (parts by weight)

[0062]

[0063]

[0064] Table 2 Proportions of Examples 10-18 (parts by weight)

[0065]

[0066]

[0067] Table 3 Comparative proportions (parts by weight)

[0068]

[0069] As can be seen from Tables 1-3, the infrared reflectivity of the polycarbonate composition of the present invention is greater than 70%, such as 71.2%-78.1%, and the notched Izod impact strength is greater than 500 J / m, such as 501-653 J / m. The distribution of the particle size D50 of titanium dioxide in Comparative Examples 1-4 is not within the scope of the present invention, and the infrared reflectivity and notched Izod impact strength of Comparative Examples 1-4 are significantly worse than those of Example 1. Comparative Example 5 uses styrene-butadiene-glycidyl ester copolymer, and the notched Izod impact strength of Comparative Example 5 is significantly worse than that of Example 1. Comparative Example 6 uses titanium dioxide particle size that is not within the scope of the present invention, and the infrared reflectivity and notched Izod impact strength are significantly worse than those of Example 1. It can be seen that the present invention uses a specific titanium dioxide particle size distribution to improve the mid-infrared reflectivity of the polycarbonate composition, and uses ethylene-glycidyl ester copolymer as a toughening agent to ensure the toughness of the polycarbonate composition.

Claims

1. A highly reflective mid-infrared polycarbonate composition, characterized in that: The polycarbonate composition comprises the following components in parts by weight: 70-85 parts of PC resin; 10-16 parts of titanium dioxide; Black pigment 0.1-1 part; 2-5 parts of toughening agent; The titanium dioxide particle size D50 and its distribution are composed of the following components by weight percentage: 2.4μm≤D50≤2.6μm 20%-30%; 0.6μm≤D50≤1.3μm 40%-50%; 0.15μm≤D50≤0.3μm 20%-40%; The toughening agent is an ethylene-glycidyl ester copolymer; the ethylene-glycidyl ester copolymer includes an ethylene copolymer grafted with glycidyl methacrylate; and / or a random terpolymer of ethylene, acrylate and glycidyl methacrylate.

2. The high-reflection mid-infrared polycarbonate composition according to claim 1, characterized in that: The polycarbonate composition comprises the following components in parts by weight: 75-80 parts of PC resin; 12-15 parts of titanium dioxide; Black pigment 0.3-0.8 parts; 3-4 parts of toughening agent.

3. The highly reflective mid-infrared polycarbonate composition according to claim 1, characterized in that: The PC resin is aromatic polycarbonate; the viscosity average molecular weight of the PC resin is 18000-25000.

4. The highly reflective mid-infrared polycarbonate composition according to claim 1, characterized in that: The black pigment is a metal oxide black pigment, and the metal oxide black pigment includes one or more of iron / chromium oxide, calcium / titanium / manganese oxide, and copper / chromium oxide.

5. The highly reflective mid-infrared polycarbonate composition according to claim 1, characterized in that: The black pigment has an oil absorption of 12-18 g / 100 g.

6. The highly reflective mid-infrared polycarbonate composition according to claim 1, characterized in that: The polycarbonate composition further comprises 0-1 part of other additives; the other additives comprise lubricants and / or antioxidants.

7. A method for preparing a polycarbonate composition with high mid-infrared reflection as claimed in any one of claims 1 to 6, comprising: The components are mixed, and the obtained premix is ​​put into a twin-screw extruder, melt-mixed, extruded and granulated to obtain a polycarbonate composition with high mid-infrared reflection.

8. The preparation method according to claim 7, characterized in that: The twin-screw extruder has a melting and mixing temperature of 240-260° C., a screw length-diameter ratio of 40:1-48:1, and a screw speed of 400-500 rpm.

9. Use of the highly mid-infrared reflective polycarbonate composition according to any one of claims 1 to 6 in mid-infrared application equipment.

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