Preparation method of transparent ABS (Acrylonitrile Butadiene Styrene) multilayer structure high internal grafting rubber powder

Abstract

The invention discloses a preparation method of transparent ABS (Acrylonitrile Butadiene Styrene) multilayer structure high internal grafting rubber powder, the grafting rubber powder is of a core-shell-core-shell four-layer structure, and the grafting rubber powder comprises an innermost layer of PB, a second layer of MMA-SM-AN (Methyl Methacrylate-SM-AN) copolymer, a third layer of PB and a fourth layer of MMA-SM-AN copolymer. The haze and the b value can be effectively reduced, and meanwhile, the dispersion form of a rubber phase is improved, so that the impact resistance of the transparent ABS is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of engineering plastics ABS, and particularly relates to a preparation method of rubber phase glue powder and application thereof. BACKGROUND

[0002] ABS is a copolymer of acrylonitrile-butadiene-styrene, is a high-strength, good-toughness, easy-to-process thermoplastic polymer material, has good forming property, and is mainly used for alloy and plastic.

[0003] Transparent ABS is prepared by adjusting the refractive index of the continuous phase MSAN and the rubber phase glue powder, so that the refractive index difference between the two phases is less than 0.005, and the transparent effect under visible light is achieved. Due to the good impact resistance, wear resistance and chemical resistance of transparent ABS, it has a wide application in transparent materials. However, due to the influence of the crosslinking degree of PB latex in the grafting process, the traditional transparent ABS glue powder has a single core-shell structure. When light passes through the product, it is refracted by the polybutadiene rubber ball, which causes the light path to deviate, and the product has a high haze value, generally greater than 3.

[0004] In CN106221114A, in order to better control the particle size of the rubber phase, a large phase region size control is adopted. By adjusting the molecular weight of the copolymer continuous phase, the size of the rubber particles as the dispersed phase can be well controlled. Almost all the rubber particles as the dispersed phase have an internal inclusion structure, and the rubber particle size is 0.3-1.2 μm. However, the haze and mechanical properties cannot be optimized at the same time. When the haze is reduced, the mechanical properties become poor.

[0005] In CN106699981A, transparent ABS is prepared by using a continuous bulk method, so that the rubber phase can be more dispersed in the matrix to reduce the haze. However, the bulk method has poor ability to control the particle size of the rubber phase, and the product has low impact resistance.

[0006] Therefore, it is a research focus to prepare a glue powder preparation method with simple synthesis, precise control of the dispersion effect of the rubber phase in the matrix, and high internal grafting rate for transparent ABS with high light transmission and high impact resistance. SUMMARY

[0007] The application provides a preparation method of transparent ABS multilayer structure high internal grafting rate glue powder, which can effectively reduce the haze and b value, improve the dispersion form of the rubber phase, and further improve the impact resistance of the transparent ABS.

[0008] The glue powder preparation method of the application not only improves the light path by increasing the internal grafting during the rubber phase emulsion polymerization process, which is beneficial to the improvement of optical properties, but also makes the rubber absorb more energy during the impact resistance process due to the multilayer structure, so as to improve the impact strength.

[0009] To achieve the above purposes, the present application is realized by the following technical solutions:

[0010] A transparent ABS multilayer structure, high inner grafting rubber powder, the grafting rubber powder is a four-layer structure of core-shell-core-shell, comprising: the innermost layer of polybutadiene, the second layer of MMA-SM-AN (methyl methacrylate-styrene-acrylonitrile) copolymer, the third layer of polybutadiene and the fourth layer of MMA-SM-AN copolymer.

[0011] The preparation method of the transparent ABS multilayer structure, high inner grafting rubber powder, comprises the following steps: the first step is inner PB (polybutadiene) polymerization, the second step is inner grafting reaction, the third step is outer PB polymerization, and the fourth step is outer grafting polymerization.

[0012] As a preferred scheme, the preparation method comprises the following steps:

[0013] (1) PB-1, emulsifier, water are added to the reactor, heated to 70-80 DEG C, after uniform mixing, the initiator is added, and the reaction is carried out for 5-10 h;

[0014] (2) After the first step reaction is completed, the temperature is lowered to 50-60 DEG C, and the mixed monomer-1 of MMA, SM and AN is added to the reactor dropwise in 1-4 h, the temperature is kept at 50-60 DEG C, after dropwise addition is completed, the reaction is continued for 1.5-3 h, preferably 2-2.5 h;

[0015] (3) After the second step reaction is completed, PB-2 and emulsifier are added, the temperature is raised to 70-80 DEG C, and the reaction is carried out for 4-8 h;

[0016] (4) After the third step reaction is completed, the mixed monomer-2 of MMA, SM and AN is added to the reactor dropwise in 1-4 h, the emulsifier, activator and initiator are added, the temperature is kept at 70-80 DEG C, and the reaction is carried out for 2-4 h;

[0017] (5) Water and coagulant are added to the reactor, the temperature is raised to 60-70 DEG C, the emulsion after the reaction is added to the coagulant dropwise in 1 h, after dropwise addition is completed, the temperature is raised to 80-90 DEG C and kept constant for 2-4 h, preferably 2.5-3 h, after the reaction is completed, the product is obtained after filtration, washing and drying.

[0018] In step (1) of the present application, the emulsifier is one or more of potassium oleate, potassium fatty acid, potassium abietate and sodium dodecyl sulfate, preferably potassium oleate.

[0019] In step (1) of the present application, the dry basis mass ratio of the emulsifier to PB-1 is 0.01:1-0.08:1, preferably 0.03:1-0.05:1.

[0020] In step (1) of the present application, the initiator is one or more of potassium persulfate, sodium persulfate, and ammonium persulfate, preferably potassium persulfate.

[0021] In step (1) of the present application, the dry basis mass ratio of the initiator to PB is 0.02:1-0.05:1, preferably 0.03:1-0.04:1.

[0022] In step (1) of the present application, the reaction time is 5-10h, preferably 5-6h.

[0023] In step (2) of the present application, MMA accounts for 50-80 parts of the mixed monomer-1, preferably 60-75 parts, SM accounts for 10-35 parts of the mixed monomer, preferably 15-30 parts, and AN accounts for 5-15 parts of the mixed monomer, preferably 10-12 parts.

[0024] In step (2) of the present application, the mass ratio of mixed monomer-1 to PB-1 is 0.25-1, preferably 0.5-0.6.

[0025] In step (2) of the present application, the dropping time is 1-4h, preferably 2-3h.

[0026] In the preparation method of the present application, the mass ratio of PB-2 to PB-1 is 1:1-1:4, preferably 1:2-1:3.

[0027] In step (4) of the present application, MMA accounts for 50-80 parts of the mixed monomer-2, preferably 60-75 parts, SM accounts for 10-35 parts of the mixed monomer, preferably 15-30 parts, and AN accounts for 5-15 parts of the mixed monomer, preferably 10-12 parts.

[0028] In the preparation method of the present application, the mass ratio of mixed monomer-1 to mixed monomer-2 is 1:1-1:3, preferably 1:1.5-1:2.5.

[0029] In step (5) of the present application, the coagulant is one or more of sulfuric acid, magnesium sulfate, and calcium chloride, preferably calcium chloride.

[0030] In step (5) of the present application, the mass ratio of the coagulant to the dry basis of the latex is 1:100-10:100, preferably 3:100-6:100.

[0031] The reactions of steps (1)-(4) of the present application are shown in the following schematic diagram, which is not limited thereto:

[0032] (1)

[0033] (2)

[0034] (3)

[0035] (4)

[0036] As shown in the schematic diagram, in step (1), the butadiene monomer self-polymerizes to form the first core layer. In step (2), some MMA / SM / AN monomers are grafted to form the second shell layer. In step (3), butadiene is added again to encapsulate the core layer, forming the third core layer. In step (4), the remaining MMA / SM / AN monomers are grafted to form the fourth shell layer, resulting in the final product. The first and third rubber layers provide good impact reduction, while the second and fourth monomer layers provide good light transmission and compatibility with the matrix.

[0037] The beneficial effects of the present invention are as follows: In the process of rubber phase emulsion polymerization, the rubber powder preparation method of the present invention not only improves the optical path by increasing internal grafting, which is beneficial to improving optical performance, but also the multilayer structure allows the rubber to absorb more energy during the impact resistance process, thereby improving the impact resistance strength. Detailed Implementation

[0038] To better understand the technical solution of the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0039] Analytical instruments:

[0040] Izod impact strength: CEAST 9050 pendulum impact tester

[0041] Transmittance / Haze: Haze Gard 1 Transmittance / Haze Meter

[0042] Tensile strength and elongation at break: Instron 5966 universal testing machine

[0043] Test method:

[0044] Izod impact strength: Standard ASTM D256

[0045] Tensile strength, elongation at break: Standard ASTM D638

[0046] Light transmittance / haze: ASTM D1003

[0047] Grafting rate test:

[0048] (1) Weigh the dried transparent ABS powder (water content less than 1%, accurate to 0.0001 g, mass is G) into a 100 ml flask, add 50 ml of acetone along the neck of the flask, attach the condenser to the flask, and reflux in a 65℃ constant temperature water bath for 2.0 hours. During this period, do not allow the water bath temperature to exceed 65℃, otherwise bumping may occur.

[0049] (2) Remove the flask and cool it to room temperature. Transfer the solution in the flask to a pre-weighed beaker and let it settle for 4 hours. Remove the supernatant. Place the beaker in a vacuum oven and dry it under vacuum at 65°C until constant weight. Weigh and calculate the dry basis mass as G1.

[0050] The grafted rubber content X (%) is calculated using the following formula:

[0051] Grafted rubber content X = G1 / G * 100%

[0052] In the formula: G1—grafted rubber mass (i.e., total of polybutyl acrylate and grafted SAN), unit: grams;

[0053] G—Sample mass (i.e., ABS grafting powder mass), unit: grams

[0054] Grafted rubber content - Formulated rubber content

[0055] Grafting efficiency η = ————————————————— × 100%

[0056] 1 - Rubber content in the formulation

[0057] Grafted rubber content - Formulated rubber content

[0058] Grafting rate π = ————————————————— × 100%

[0059] Rubber content in formulation

[0060] The parts mentioned in Examples 1-5 are molar parts, while the parts mentioned in Examples 6-10 and the comparative examples are mass parts.

[0061] Example 1

[0062] (1) Add 100g of PB-1 and 1g of potassium oleate to the reactor, heat to 70℃, mix evenly, add 2g of potassium persulfate, and react at a constant temperature for 5h.

[0063] (2) After the first step reaction is completed, the temperature is lowered to 50°C. 25g of mixed monomer-1 of MMA, SM and AN (70% MMA, 20% SM and 10% AN) is added evenly to the reactor within 1 hour. The temperature is kept at 50°C. After the addition is completed, the reaction continues for 2 hours.

[0064] (3) After the second step reaction is completed, add 100g PB-2 and 1g potassium oleate, raise the temperature to 70℃, and react at a constant temperature for 4h;

[0065] (4) After the third step reaction is completed, 25g of mixed monomer-2 of MMA, SM and AN (of which MMA is 70%, SM is 20% and AN is 10%) is added evenly to the reactor within 1 hour, 1g of potassium oleate and 2g of potassium persulfate are added, and the temperature is kept constant at 70℃ for 2 hours.

[0066] (5) Add a certain amount of water and 2.5g of sulfuric acid to the reactor, raise the temperature to 60℃, and uniformly add the emulsion after the reaction to the coagulant within 1h. After the addition is completed, raise the temperature to 80℃ and keep it constant for 3h. After the reaction is completed, filter, wash and dry to obtain a high internal grafted adhesive powder with a four-layer structure.

[0067] Examples 2-6:

[0068] According to the formulations in Table 1, the adhesive powders of Examples 2-6 were prepared respectively, with the remaining reaction conditions and product parameters being the same as those of Example 1. Table 1 shows the raw materials and reaction conditions for Examples 1-6.

[0069] Table 1. Raw materials and reaction conditions for Examples 1-6

[0070]

[0071]

[0072] Comparative Example 1

[0073] Transparent ABS with a core-shell structure, using polybutadiene as the core and grafting MMA-SM-AN polymer.

[0074] (1) Add 200 parts of polybutadiene latex (preparation method see "ABS Resin Production Practice and Application" - Suo Yanhui) (product parameters: particle size 380nm, solid content 55%, viscosity 200mPa / s), 100 parts of water, 1 part of potassium oleate (Qingdao Ruinuo, potassium oleate soap), and 2 parts of potassium persulfate to the reaction vessel and heat to 50℃;

[0075] (2) Add 50 parts of mixed monomers (70% MMA, 20% SM, 10% AN) to the reactor. At the same time, heat the reactor to 60°C and add the monomers dropwise for 1 hour. After the addition is complete, keep the temperature at 70°C for 0.5 hours. Stop the reaction after the monomers are consumed.

[0076] Comparative Example 2

[0077] (1) Add 200 parts of polybutadiene latex prepared in Comparative Example 1, 100 parts of water, 3 parts of fatty soap (Qingdao Shui Ruocheng Fatty Acid Potassium Soap), and 2 parts of sodium persulfate to the reaction vessel and heat to 50°C.

[0078] (2) Add 100 parts of mixed monomers (50% MMA, 35% SM, 15% AN) to the reactor. At the same time, heat the reactor to 60°C and add the monomers dropwise for 1 hour. After the addition is complete, keep the temperature at 70°C for 0.5 hours. Stop the reaction after the monomers are consumed.

[0079] Coagulation and Drying: The grafted emulsion prepared in the above examples was coagulated by adding 5% dilute sulfuric acid at 70°C, followed by vacuum filtration and fluidized bed drying (air velocity 180 m / s). 3 After drying at 70℃ for 0.5-1h, ABS grafted powder is obtained.

[0080] ABS resin was prepared by blending and granulation: 24 parts of the above-mentioned ABS grafted powder were mixed with 76 parts of XT-500 (LG Chem), 0.1 parts of antioxidant 1010 (BASF, Germany), 0.1 parts of antioxidant 618 (Panhua Chemical (Shanghai) Co., Ltd.), 0.2 parts of magnesium stearate, and 2 parts of N,N-ethylene bis-stearamide (Shandong Li'ang New Material Co., Ltd.) in a high-speed kneader for 5 minutes. The mixture was then melt-granulated and blended in a twin-screw extruder at 220°C to obtain ABS resin granules. The granules were dried in an oven at 80°C for 2 hours, and then injection-molded for mechanical and optical property testing.

[0081] Examples 1-6 and Comparative Examples 1-2: The prepared ABS powder was agglomerated and dried, then blended and granulated to prepare ABS resin for testing. The properties are shown in Table 3.

[0082] Table 3. Performance test results of the examples and comparative examples.

[0083]

[0084] As shown in Table 3, the adhesive powder prepared using the method of this invention during the grafting process can produce transparent ABS grafted adhesive powder with a high grafting rate. The process is stable, with low residue content, improving production efficiency and core-shell distribution, thereby enhancing the optical properties (transmittance and haze) of transparent ABS. This is because, using the preparation method in this patent, the transparent ABS adhesive powder has a four-layer structure of core-shell-core-shell. During the grafting process, more grafting monomers can enter the interior of the latex particles, expanding the grafting space, increasing the size of the rubber particles, improving the utilization efficiency of the rubber in terms of space, enhancing the toughening effect of the rubber, and most importantly, the multi-layer structure can increase the grafting rate of the rubber, increase the compatibility with the matrix phase, reduce light loss during transmission, and greatly reduce the haze of the product. Ordinary core-shell structure transparent ABS has a low grafting rate, and light transmission is easily deflected by the refraction of rubber particles, resulting in performance deviations.

Claims

1. A transparent ABS multilayer structure high internal grafting of a rubber powder, the grafted rubber powder is a four-layer structure of core-shell-core-shell, comprising: The innermost layer is PB, the second layer is MMA-SM-AN copolymer, the third layer is PB, and the fourth layer is MMA-SM-AN copolymer.

2. A method of producing the crumb of claim 1, comprising the steps of: The first step is butadiene polymerization of the inner layer, the second step is inner grafting reaction, the third step is butadiene polymerization of the outer layer, and the fourth step is outer grafting polymerization.

3. The method of claim 2, wherein, The method comprises the following steps: (1) adding PB-1, emulsifier and water into a reactor, heating to 70-80℃, mixing uniformly, then adding initiator, and reacting for 5-10h; (2) cooling to 50-60℃, adding mixed monomers-1 of MMA, SM and AN into the reactor dropwise within 1-4h, keeping the temperature at 50-60℃, continuing to react for 1.5-3h, preferably 2-2.5h after the dropwise addition is completed; (3) adding PB-2 and emulsifier, heating to 70-80℃, and keeping the temperature constant for 4-8h; (4) adding mixed monomers-2 of MMA, SM and AN into the reactor uniformly within 1-4h, adding emulsifier, activator and initiator, keeping the temperature at 70-80℃, and keeping the temperature constant for 2-4h; (5) adding water and coagulant into the reactor, heating to 60-70℃, adding the product of step (4) into the reactor dropwise uniformly within 1h, heating to 80-90℃ after the dropwise addition is completed, keeping the temperature constant for 2-4h, preferably 2.5-3h, and then filtering, washing and drying to obtain the product.

4. The method of claim 3, wherein, In step (1), the emulsifier is one or more of potassium oleate, potassium fatty acid, potassium abietate and sodium dodecyl sulfate, and the initiator is one or more of potassium persulfate, sodium persulfate and ammonium persulfate.

5. The method according to claim 3 or 4, characterized in that, In step (2), the amount of MMA in the mixed monomers-1 is 50-80 parts, preferably 60-75 parts, the amount of SM is 10-35 parts, preferably 15-30 parts, and the amount of AN is 5-15 parts, preferably 10-12 parts.

6. The method according to any one of claims 3-5, characterized in that, In step (2), the mass ratio of mixed monomers-1 to PB-1 is 0.25-1, preferably 0.5-0.

6.

7. The method according to any one of claims 3-6, characterized in that, The mass ratio of PB-2 to PB-1 is 1:1-1:4, preferably 1:2-1:

3.

8. The method according to any one of claims 3 to 7, characterized in that, In step (4), the amount of MMA in the mixed monomers-2 is 50-80 parts, preferably 60-75 parts, the amount of SM is 10-35 parts, preferably 15-30 parts, and the amount of AN is 5-15 parts, preferably 10-12 parts.

9. The method according to any one of claims 3-8, characterized in that, The mass ratio of mixed monomers-1 to mixed monomers-2 is 1:1-1:3, preferably 1:1.5-1:2.

5.

10. The method according to any one of claims 3-9, characterized in that, The coagulant is one or more of sulfuric acid, magnesium sulfate and calcium chloride.

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