Low-temperature-resistant ASA material and preparation method thereof

Abstract

The invention discloses a low-temperature-resistant ASA material and a preparation method thereof, and belongs to the technical field of high polymer material modification. The ASA material is prepared from the following raw materials in parts by weight: 65 to 75 parts of AS resin, 25 to 35 parts of ASA rubber powder, 2 to 5 parts of nano silicon dioxide and 0.2 to 1 part of gamma-aminopropyltriethoxysilane. Compared with the prior art, by adding the modified silicon dioxide, the weather resistance of the material is not influenced while the low-temperature toughness of the ASA material is improved, and the problem that the low-temperature toughness of the automotive exterior ASA material is low is solved.

Description

Technical Field

[0001] The present invention relates to the field of polymer material modification, and in particular to a low-temperature resistant ASA material and a preparation method thereof. Background Art

[0002] ASA resin is widely used in automotive exteriors, outdoor building materials and other fields due to its excellent weather resistance. The toughness of ASA mainly depends on the glass transition temperature of the acrylic rubber phase in its core-shell structure, which is about -40°C. When the temperature is close to or lower than the glass transition temperature of the rubber phase, the movement of the molecular segments freezes, and the rubber phase changes from an elastic state to a glassy state, losing its energy dissipation ability and being more susceptible to fracture on a macroscopic scale. The conventional idea of ​​increasing low-temperature toughness is to add silicone rubber or polybutadiene rubber with a lower glass transition temperature, but this will seriously affect the weather resistance of the material. The low-temperature resistant ASA material developed by the present invention can not only have good toughness at low temperatures, but also maintain the excellent weather resistance of the ASA material. Summary of the Invention

[0003] In view of the deficiencies in the prior art, the present invention proposes a low-temperature resistant ASA material and a preparation method thereof.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] The first aspect of the present invention relates to an ASA material comprising the following raw materials in parts by weight:

[0006] 65-75 parts of AS resin, 25-35 parts of ASA rubber powder, 2-5 parts of nano silicon dioxide and 0.2-1 part of 3-mercaptopropyltriethoxysilane.

[0007] In some examples, the ASA material further includes 0.5-0.8 parts of a light aging agent, 0.2-0.4 parts of an antioxidant, and 0.5-1 parts of a color powder.

[0008] As a further solution of the present invention: the AS resin is a high molecular weight copolymer of acrylonitrile and styrene, wherein the molecular weight is 70,000-90,000, the styrene content is 50-70%, and the acrylonitrile content is 30-50%.

[0009] As a further solution of the present invention: the ASA resin is a core-shell structured high-rubber powder, the core of which is butyl acrylate with a content of 50-60%, and the shell graft is a copolymer of styrene and acrylonitrile.

[0010] As a further solution of the present invention: the ASA resin particle size is 150-250nm.

[0011] As a further solution of the present invention: the nano-silica is not surface-modified and has a hydrophilic surface; the particle size is 10-100 nm.

[0012] As a further embodiment of the present invention: the surface modifier is 3-mercaptopropyltriethoxysilane.

[0013] As a further solution of the present invention: the antioxidant is prepared by compounding hindered phenols and phosphites in a mass ratio of 1:1-1:1.5.

[0014] As a further solution of the present invention: the photoaging agent is prepared by compounding hindered amines and benzophenones in a mass ratio of 1:0.5-1:1.

[0015] As a further solution of the present invention: the toner is a high-pigment carbon black masterbatch, wherein the carbon black content is 50% and the characteristic particle size of the carbon black is 15 nm.

[0016] The second aspect of the present invention relates to a method for preparing an ASA material, comprising the following steps:

[0017] 2-5 parts by weight of nano-silica and 0.2-1 parts by weight of 3-mercaptopropyltriethoxysilane are pre-mixed, and 25-35 parts by weight of ASA rubber powder and 65-75 parts by weight of AS resin are added in sequence and mixed; the ASA material is obtained after melt molding.

[0018] Specifically, the molding process uses a twin-screw extruder, and the temperatures of each zone are set to 150°C, 220°C, 220°C, 220°C, 210°C, 210°C, 200°C, 200°C, 200°C, and 220°C. The main engine speed is 400 rpm and the feed rate is 200 kg / h.

[0019] Beneficial effects of the present invention:

[0020] Nano-silica is surface-modified with 3-mercaptopropyltriethoxysilane through premixing, and good compatibility is formed with ASA rubber powder, thereby enhancing the entanglement between nanoparticles and ASA chain segments; finally, the ASA rubber powder and nano-silica are uniformly dispersed in the ASA resin through a twin-screw extruder. Through the above method, the two components synergistically toughen, and the main working principles are: first, elastomer + rigid particle composite toughening: ASA provides macro-scale energy dissipation (cavitation), and nano-silica provides micro-crack deflection, forming a multi-level toughening network; second, low-temperature brittleness is suppressed: the rubber phase maintains flexibility, and nano-silica hinders the low-temperature crystallization of the molecular chain, synergistically reducing the brittle-to-tough transition temperature of the matrix. Through the above mechanism of action, the low-temperature toughness of the ASA material is increased while the weather resistance of the material is not affected. This invention solves the problem of low low-temperature toughness of ASA materials for automotive exteriors. DETAILED DESCRIPTION

[0021] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0022] The specific information of the raw materials used in the following examples and comparative examples is as follows:

[0023] AS resin, produced by Chi Mei Company;

[0024] ASA rubber powder, produced by Mitsubishi Rayon Co., Ltd. of Japan, brand SX-006;

[0025] Nano-silicon dioxide, produced by Anhui Jingye Nano-Tech Co., Ltd., brand Y100-05;

[0026] 3-Mercaptopropyltriethoxysilane, produced by Nanjing Luoen Silicon, brand KH series;

[0027] Antioxidant 1076 and Antioxidant 168 are both produced by BASF in Germany;

[0028] Toner, high pigment carbon black masterbatch;

[0029] All materials are commercially available common products.

[0030] It is understood that the above raw materials and reagents are only examples of some specific embodiments of the present invention, which make the technical solution of the present invention clearer, and do not mean that the present invention can only adopt the above reagents. The specific scope in the claims shall prevail. In addition, the "parts" described in the examples and comparative examples, unless otherwise specified, refer to parts by weight.

[0031] Any range described in the present invention includes the end value and any numerical value between the end values ​​and any sub-range formed by the end value or any numerical value between the end values.

[0032] Weigh the components according to the proportions in Table 1, fully premix and mix to obtain a uniform mixture; add the mixture into a twin-screw extruder, melt, extrude, and granulate to obtain a low-temperature resistant ASA material;

[0033] Among them, the screw diameter of the twin-screw extruder is 40 mm, the length-to-diameter ratio L / D=36, and the screw combination is equipped with a high-dispersion thread block to help ASA rubber powder and nano-silica be fully dispersed in the AS resin. The barrel controls the temperature in sections, and the temperatures of each zone are set to 150°C, 220°C, 220°C, 220°C, 210°C, 210°C, 200°C, 200°C, and 220°C. The main engine speed is 400 rpm and the feed rate is 200 kg / h.

[0034] Table 1

[0035]

[0036] The ASA materials prepared in Examples 1-4 and Comparative Examples 1-3 were first dried in a blast oven at 80-90° C. for 3-4 hours to fully dry the moisture, and then injection molded into strips and plates on an injection molding machine. The materials were conditioned under standard conditions for 24 hours to facilitate performance testing. The test standards and test conditions are as follows:

[0037] Density test: According to ISO 1183-1 standard, the test size is 40*10*4mm;

[0038] Tensile strength test: According to ISO 527-2 standard, the sample size is 135*10*4mm, and the tensile speed is 50mm / min;

[0039] Flexural strength and flexural modulus tests: performed according to ISO 178, with specimen dimensions of 80*10*4mm, a bending speed of 2mm / min, and a span of 64mm.

[0040] Low-temperature Charpy notched impact strength test: conducted according to ISO 179-1 standard, specimen size 80*10*4mm, A-notch, 4J pendulum, test temperature -30℃;

[0041] Vicat softening temperature test: carried out according to ISO 306 standard, sample size is 10*10*4mm, load is 50N, heating rate is 50℃ / h;

[0042] Weathering test: GB / T 16422.2 is used for testing for 1000 hours. After the test, GB / T-250 gray scale is used for evaluation, where level 1 represents the worst and level 5 represents the best. Generally speaking, customers judge that level 4 or higher is qualified.

[0043] The performance test results are shown in Table 2.

[0044] Table 2

[0045]

[0046]

[0047] From the comparison of the test results of Examples 1-3 and Comparative Examples 1-3, it can be seen that the -30°C low-temperature simply supported beam notched impact strength of the low-temperature resistant ASA material is significantly improved.

[0048] From Example 1 and Comparative Example 2, the -30°C low-temperature simply supported beam impact strength and gray card grade of the nano-silica that has not been modified with 3-mercaptopropyltriethoxysilane are relatively poor, reflecting that the nano-silica modified with 3-mercaptopropyltriethoxysilane has a positive significance for improving the low-temperature toughening effect and xenon lamp aging resistance of the system.

[0049] From Example 4, after the nano-silica is modified with an excess of 3-mercaptopropyltriethoxysilane, its -30°C low-temperature simply supported beam impact strength and gray card grade are relatively poor. Excessive 3-mercaptopropyltriethoxysilane may cause the coating layer of nano-silica to be too thick during the modification process, which will reduce the compatibility of nano-silica with ASA resin, thereby leading to a decrease in -30°C low-temperature simply supported beam impact strength and a deterioration of the gray card grade.

[0050] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0051] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the invention as claimed.

Claims

1. An ASA material, characterized in that It includes the following raw materials in parts by weight: 65-75 parts of AS resin, 25-35 parts of ASA rubber powder, 2-5 parts of nano silicon dioxide, and 0.2-1 part of 3-mercaptopropyltriethoxysilane.

2. The ASA material according to claim 1, characterized in that The AS resin is a copolymer of acrylonitrile and styrene, wherein the molecular weight is 70,000-90,000, the styrene content is 50-70%, and the acrylonitrile content is 30-50%.

3. The ASA material according to claim 1, characterized in that The ASA resin is a core-shell structured high-rubber powder, wherein the core is butyl acrylate with a content of 50-60%, and the outer shell graft is a copolymer of styrene and acrylonitrile.

4. The ASA material according to claim 1, characterized in that The ASA resin particle size is 150-250 nm.

5. The ASA material according to claim 1, characterized in that The invention also includes 0.5-0.8 parts of photoaging agent, 0.2-0.4 parts of antioxidant and 0.5-1 parts of color powder.

6. The ASA material according to claim 5, characterized in that The antioxidant comprises a hindered phenol antioxidant and a phosphite antioxidant in a weight ratio of 1:1-1:1.

5.

7. The ASA material according to claim 5, characterized in that The toner is a carbon black masterbatch, wherein the carbon black content is 50% and the characteristic particle size of the carbon black is 15 nm.

8. The ASA material according to claim 1, characterized in that The nano-silicon dioxide particle size is 10-100 nm.

9. A method for preparing an ASA material, comprising the following steps: Take 2-5 parts by weight of nano-silica and 0.2-1 parts by weight of 3-mercaptopropyltriethoxysilane and pre-mix them, then add 25-35 parts by weight of ASA rubber powder and 65-75 parts by weight of AS resin and mix them; The ASA material is obtained after melt molding.

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