PVC / ABS alloy and preparation method thereof

Abstract

The application discloses a PVC / ABS alloy and a preparation method thereof, and belongs to the technical field of polymer materials. The product uses organic maleimide derivatives and a specific acid absorber component compounded with a thiol methyl tin to jointly serve as a heat stabilizing component. The product can significantly improve the heat stability, can still maintain low discoloration under a processing environment of up to 200 DEG C, and can also maintain sufficient impact resistance, and has excellent comprehensive performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to a PVC / ABS alloy and a preparation method thereof. BACKGROUND

[0002] The PVC / ABS alloy has both the flame retardant performance and corrosion resistance of PVC (polyvinyl chloride) resin and the mechanical performance and processing performance of ABS resin, and is widely used in the technical fields of electronic appliances, building, agriculture and forestry, etc.

[0003] However, the PVC / ABS alloy has poor thermal stability due to the low decomposition temperature of PVC resin, and is prone to discoloration under processing or heating environment, and the processing performance is not ideal. SUMMARY

[0004] Based on the defects of the prior art, the present application aims to provide a PVC / ABS alloy, which uses organic maleimide derivatives and thiomethyl tin to compound specific acid absorber components as thermal stabilizing components, so as to significantly improve the thermal stability of the product, maintain low discoloration under a processing environment of up to 200℃, and also maintain sufficient impact resistance, and has excellent comprehensive performance.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0006] A PVC / ABS alloy comprises the following components by weight:

[0007] PVC resin 100 parts, ABS resin 5-50 parts, toughening agent 3-5 parts, thiomethyl tin 3-5 parts, maleimide derivatives 0.2-0.6 parts, acid absorber 3-8 parts, and antioxidant 0.4-1 part.

[0008] The acid absorber comprises calcium carbonate and stearate.

[0009] The PVC / ABS alloy system is based on the thermal stability characteristics of PVC resin itself, and the appearance discoloration problem is very easy to occur during processing or heating, which leads to a large color difference of the product after heat retention, and some products need to be additionally painted after production, which is complicated. Therefore, people try to introduce some organic heat stabilizers that can passivate the reactive groups of the resin system into the PVC / ABS alloy to inhibit the discoloration effect of the product during thermal decomposition, or introduce some high-whiteness filler particles that are not easy to decompose as a compounded component to reduce the color difference change value of the product after heat retention. However, the current methods have very limited improvement on the processing and appearance performance of the product, and some systems will have incompatibility problems after introducing the additives. Due to the difference between the resin systems, some heat stabilizers commonly used in PVC resins will cause the performance of the product to be equivalent or worse than the blank product at some higher processing temperatures (for example, 200 DEG C) after being introduced into the PVC / ABS alloy; on the other hand, the mechanical properties of the product may also be weakened, and the use performance cannot be considered. Therefore, in the technical scheme of the present application, according to the existing defects and characteristics of the PVC / ABS alloy, the product in the PVC / ABS alloy system uses thiomethyl tin as the main heat stabilizer. Compared with other types of heat stabilizers, this component can effectively inhibit the decomposition behavior of the alloy resin under high temperature conditions, and quickly capture free radicals and peroxides in the matrix component. However, the thermal stability of the product is very limited with only thiomethyl tin, and it needs to be assisted by a certain amount of maleimide derivative to synergize. Both of them have high compatibility with the resin matrix, and can greatly improve the thermal environmental inertia of the resin matrix. In addition, in order to deal with the acidic substances in the organic system of the product during thermal processing (which can participate in or catalyze the oxidation reaction of PVC resin), the heat stabilizer in the product component of the present application additionally introduces a specific acid absorber composed of calcium carbonate and stearate, which inhibits the influence of acidic substances on the resin matrix during production and processing, and guarantees the long-term heat retention appearance stability. If the three components are missing or replaced by other common heat stabilizers for plastic products, not only the color stability of the product cannot be guaranteed, but also the impact strength of the product will be affected, so it cannot be normally applied to some electronic and electrical shell products.

[0010] Preferably, in the PVC / ABS alloy, the total mass percentage content of PVC resin and ABS resin is ≥80%.

[0011] Preferably, in the PVC / ABS alloy, the ABS resin is one or any two of the range values of 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 40 parts, 50 parts by weight, the toughening agent is one or any two of the range values of 3 parts, 4 parts, 4.5 parts, 5 parts by weight, the thiol methyl tin is one or any two of the range values of 3 parts, 3.5 parts, 4 parts, 5 parts by weight, the maleimide derivative is one or any two of the range values of 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts by weight, the acid absorbent is one or any two of the range values of 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, 6 parts, 7 parts, 8 parts by weight, and the antioxidant is one or any two of the range values of 0.4 parts, 0.6 parts, 0.7 parts, 0.8 parts, 1 part by weight.

[0012] Preferably, the thiol methyl tin includes at least one of a coordination type thiol methyl tin and a non-coordination type thiol methyl tin.

[0013] Preferably, the thiol methyl tin is a coordination type thiol methyl tin.

[0014] Preferably, the thiol methyl tin includes at least one of (CH3)3Sn2(SCH2COOC8H 17 )5, CH3Sn(SCH2COOC8H 17 )3, and (CH3)2Sn(SCH2COOC8H 17 )2.

[0015] The molecular weight of the thiol methyl tin differs based on the difference in whether it is a coordination configuration, and when a coordination type thiol methyl tin with a larger molecular weight is selected in the PVC / ABS alloy described in the present application, the appearance color stability of the product under heat retention conditions is more optimal.

[0016] Preferably, the PVC resin has an apparent density of 0.47-0.54 g / mL according to GB / T20022-2005.

[0017] Preferably, the PVC resin has an average polymerization degree of 400-1000.

[0018] Further preferably, the PVC resin has an average polymerization degree of one or any two of the range values of 400, 500, 600, 700, 800, 1000.

[0019] Further preferably, the PVC resin has an average polymerization degree of 600-750.

[0020] Due to the different average degree of polymerization of PVC resin matrix, the compatibility and processing dispersibility of the product with heat-stabilizing functional additives also vary. When PVC resin within the above range is preferred, the product can not only ensure sufficient impact resistance, but also have better thermal stability.

[0021] Preferably, the average degree of polymerization of the PVC resin is determined according to the GB / T 5761-2018 standard.

[0022] Preferably, the melt flow rate of the ABS resin at 220°C and 10kg load, according to ISO 1133-2011, is 7-20g / 10min.

[0023] Preferably, the molar ratio of acrylonitrile, succinic acid and styrene monomers in the ABS resin is (15-25):(15-25):(50-65).

[0024] Preferably, the maleimide derivative includes at least one of N-substituted maleimide, alkyl-substituted maleimide, and phenyl-substituted maleimide.

[0025] More preferably, the maleimide derivative includes N-phenyl-substituted maleimides.

[0026] More preferably, the N-phenyl-substituted maleimide includes at least one of N-phenylmaleimide and N,N'-(4,4'-methylenediphenyl)bismaleimide.

[0027] In the products described in this invention, maleimide derivatives need to be used in combination with thiol-type organotin and acid scavengers. In this system, maleimide derivatives with N-phenyl substituents are more effective, and the prepared products have better overall performance.

[0028] Preferably, in the acid absorbent, the mass ratio of calcium carbonate to stearate is 1:(0.05-0.2).

[0029] More preferably, the mass ratio of calcium carbonate to stearate is one or any two of the following: 1:0.05, 1:0.06, 1:0.08, 1:0.1, 1:0.12, 1:0.15, 1:0.16, 1:0.18, 1:0.2.

[0030] Preferably, the average particle size of the calcium carbonate is 1–5 μm.

[0031] More preferably, the average particle size of the calcium carbonate is 2 to 3 μm.

[0032] As the main acid-absorbing inorganic component, the particle size of calcium carbonate is related to its dispersibility in the product and its absorption area for acidic substances. Different particle sizes result in different specific surface areas, which naturally leads to different absorption efficiencies for acidic substances. However, the dispersibility will also be affected, resulting in different impact resistance properties of the product. When the average particle size of the calcium carbonate described in this invention is preferably within the above-mentioned range, the product can achieve both better thermal retention appearance stability and impact resistance.

[0033] The average particle size of the calcium carbonate was confirmed by direct testing with a laser particle size analyzer.

[0034] Preferably, the stearate includes at least one of aluminum distearate, calcium stearate, and magnesium stearate.

[0035] Preferably, the toughening agent includes at least one of methyl methacrylate-acrylate copolymer, acrylonitrile-butyl acrylate-styrene terpolymer, and chlorinated polyethylene.

[0036] Based on the requirements of mechanical properties, those skilled in the art can select appropriate toughening agents for use according to the actual situation. As long as it does not affect the normal function of the key components with thermal stability improvement function in the product of the present invention, it will not be significantly affected.

[0037] Preferably, the PVC / ABS alloy further comprises 1 to 2 parts of processing aids.

[0038] Preferably, the processing aid includes at least one of a lubricant, an antistatic agent, and a flame retardant.

[0039] It should be noted that, without compromising the technical effect of the product described in this invention, those skilled in the art may introduce suitable processing aids into the product according to actual needs. In addition to the types described above in this invention, other components such as dispersants and preservatives may also be introduced to enhance the product's antistatic, anti-corrosion, and flame-retardant effects. The technical solution of this invention does not impose exclusive restrictions on processing aids.

[0040] Preferably, the antioxidant is at least one of hindered phenolic antioxidants and phosphite antioxidants.

[0041] More preferably, the antioxidant is a mixture of hindered phenolic antioxidants and phosphite antioxidants in a mass ratio of (1-2):1.

[0042] Preferably, the lubricant is at least one of wax-based lubricants, ester-based lubricants, and amide-based lubricants.

[0043] It should be noted that the selection of antioxidants and lubricants described in this invention is only a preferred choice. In actual production and use, the PVC / ABS alloy described in this invention can select more suitable antioxidants and lubricants according to actual needs, and is not limited to the preferred types described in this invention.

[0044] Another object of the present invention is to provide a method for preparing the PVC / ABS alloy, comprising the following steps:

[0045] The components other than the toughening agent are heated to 90-100°C and mixed evenly. Then the toughening agent is added and mixed evenly. After cooling to 75-80°C, the mixture is placed in a screw extruder for melt extrusion and granulation to obtain the PVC / ABS alloy.

[0046] Preferably, the temperature during melt extrusion granulation is 100–180°C.

[0047] The preparation method of the PVC / ABS alloy described in this invention has simple operation steps and can achieve industrial-scale production.

[0048] Another object of the present invention is to provide the application of the PVC / ABS alloy in the manufacture of electronic and electrical housings.

[0049] Another object of the present invention is to provide an electronic and electrical housing comprising the PVC / ABS alloy described herein.

[0050] The PVC / ABS alloy described in this invention has extremely high thermal stability. It can maintain good appearance and color stability even after injection molding and other processing activities at temperatures above 200°C. At the same time, the product has sufficient impact resistance, making it very suitable for electronic and electrical enclosures that require certain mechanical properties and need to ensure sufficient appearance stability during processing or heating.

[0051] The beneficial effects of the present invention are that it provides a PVC / ABS alloy, which uses an organic maleimide derivative and a specific acid scavenger component combined with methyl tin mercaptan as a heat stabilizing component. This not only significantly improves the heat stability of the product, but also maintains low discoloration in processing environments up to 200°C. At the same time, the product also maintains sufficient impact resistance, resulting in excellent overall performance. Detailed Implementation

[0052] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments and comparative examples. The purpose of this description is to provide a detailed understanding of the invention, not to limit its scope. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this invention. Unless otherwise specified, the experimental reagents and instruments involved in the implementation of this invention are commonly used reagents and instruments.

[0053] Examples 1-14

[0054] An embodiment of the PVC / ABS alloy and its preparation method described in this invention is shown in Table 1.

[0055] The components other than the toughening agent and ABS resin are heated to 90-100°C and mixed evenly. Then the toughening agent and ABS resin are added and mixed evenly. After cooling to 75-80°C, the mixture is placed in a twin-screw extruder for melt extrusion and granulation to obtain the PVC / ABS alloy.

[0056] During the melt blending extrusion of the components, the temperature zones of the twin-screw extruder are set as follows: Zone 1: 100℃, Zone 2: 150℃, Zone 3: 165℃, Zone 4: 165℃, Zone 5: 165℃, Zone 6: 165℃, Zone 7: 165℃, Zone 8: 165℃, Zone 9: 160℃. The screw speed is 150 rpm, and the screw length-to-diameter ratio is 40:1.

[0057] Comparative Examples 1-14

[0058] The only difference between each comparative example and the embodiment is the type and ratio of components, as shown in Table 2.

[0059] In the components described in each embodiment and comparative example,

[0060] The PVC resin 1 is Formosa Plastics B-57, with an average degree of polymerization of 620.

[0061] The PVC resin 2 is DG-700 produced in Dagu, Tianjin, with an average degree of polymerization of 700.

[0062] The PVC resin 3 is P400 produced by Xinjiang Zhongtai, with an average degree of polymerization of 400.

[0063] The PVC resin 4 is HG-1000F produced by Hanwha Chemical, with an average degree of polymerization of 1000.

[0064] The ABS resin is ABSDG-MG29 produced in Dagu, Tianjin, with a melt flow rate of 8.3 g / 10 min at 220℃ and 10 kg load.

[0065] The toughening agent 1 is PARALOID KM-355P, a methyl methacrylate-acrylate copolymer, produced by Rohm and Haas Chemical.

[0066] The toughening agent 2 is Kane Ace B-564, a methyl methacrylate-butadiene-styrene terpolymer manufactured by Kaneka Corporation of Japan.

[0067] The thiol methyltin 1 is a coordinated thiol methyltin prepared according to Example 1 of CN101768184B specification, (CH3)3Sn2(SCH2COOC8H 17 5;

[0068] The methyltin thiol 2 is SW977 produced by Hubei Benxing, a non-coordinated methyltin thiol, CH3Sn(SCH2COOC8H 17 )3 and (CH3)2Sn(SCH2COOC8H 17 A mixture of 2;

[0069] The thiol methyltin 3 is YT181 produced by Yunnan Tin Industry, a non-coordinated thiol methyltin, CH3Sn(SCH2COOC8H 17 )3 and (CH3)2Sn(SCH2COOC8H 17 A mixture of 2;

[0070] The maleic acid-type methyltin is DX-650 produced by Jianhua Dongxu.

[0071] The calcium-zinc stabilizer is commercially available hydrotalcite with an average size of 5μm.

[0072] The maleimide derivative 1 is N-phenylmaleimide produced by Suzhou Haofan Biotechnology Co., Ltd.

[0073] The maleimide derivative 2 is N,N'-(4,4'-methylenediphenyl)bismaleimide produced by Suzhou Haofan Biotechnology Co., Ltd.

[0074] The maleimide derivative 3 is cyclohexylmaleimide produced by Suzhou Haofan Biotechnology Co., Ltd.

[0075] The silicone resin is MB50-002 manufactured by Dow Corning.

[0076] The calcium carbonate 1 is FilmLink 525 produced by Imerys, with an average particle size of 2.7 μm;

[0077] The calcium carbonate 2 is Omyacarb 1AT-IP produced by Omya, with an average particle size of 2.4 μm;

[0078] The calcium carbonate 3 is EP698805-CU produced by Omya, with an average particle size of 1.1 μm;

[0079] The calcium carbonate 4 is LSP ECO produced by 20MICRONS LTD-BHIWAND, with an average particle size of 3.5 μm;

[0080] The stearate 1 is calcium stearate, a product manufactured by Jiangxi Hongyuan Chemical Co., Ltd.

[0081] The stearate 2 is magnesium stearate, a product manufactured by Jiangxi Hongyuan Chemical.

[0082] The antioxidant is a commercially available hindered phenolic antioxidant and phosphite antioxidant: antioxidant 1010 and antioxidant 627A are compounded in a mass ratio of 2:1;

[0083] The lubricant is commercially available oxidized polyethylene wax.

[0084] Unless otherwise specified, all components and raw materials used in the embodiments and comparative examples of this invention are commercially available, and the same type of components and raw materials are used in each parallel experiment.

[0085] Table 1

[0086]

[0087]

[0088] Table 2

[0089]

[0090] To verify the performance of the product described in this invention, the products prepared in each embodiment and comparative example were subjected to the following performance tests, the specific steps of which are as follows:

[0091] (1) Heat retention color difference test: Standard color swatches of each product were injection molded at 200℃. The L1, a1, and b1 values ​​were measured using a colorimeter. Simultaneously, parallel samples were plasticized in the injection molding machine and heat-retained at 200℃ for 5 minutes. Three color swatches were continuously injection molded. The L2, a2, and b2 values ​​of the third color swatch were measured, and the color difference was calculated with the normally injection molded color swatches: DE=[(L2-L1)] 2 +(a2-a1) 2 +(b2-b1) 2 ] 1 / 2

[0092] (2) Impact resistance test: The impact resistance of the test specimens shall be tested in accordance with GB / T 1843-2008.

[0093] The test results are shown in Tables 3 and 4.

[0094] Table 3

[0095]

[0096] Table 4

[0097]

[0098] As shown in Tables 3 and 4, the product of this invention has excellent processing performance. After the heat retention test, the color difference value of the product before and after the heat retention test can be maintained within 6.5, and in the impact resistance test, the impact resistance of the product can reach 18kJ / m. 2 The above-mentioned performance, both in terms of processing and application, meets the application standards. This is mainly due to the synergistic effect of the organic maleimide derivative and the thiol methyltin compound acid scavenger in the product as heat-stabilizing components.

[0099] In contrast, Comparative Example 1 and Comparative Example 2 lacked maleimide derivative and methyltin mercaptan, respectively. It can be seen that the color difference values ​​of both after the heat retention test were greater than those of the example products. On the other hand, if these two substances were replaced with conventional PVC heat stabilizers, as shown in Comparative Examples 5 and 6 and Comparative Example 8, the products not only failed to achieve thermal stability in appearance, but even their impact resistance was difficult to guarantee.

[0100] As can be seen from Comparative Examples 3 and 4, calcium carbonate, as an acid absorber, needs to be used in combination with stearate. Otherwise, even if the weight ratio of the added components remains unchanged, it still cannot guarantee both the appearance stability and mechanical properties of the product. If too much is added, as shown in Comparative Example 7, although the product can achieve better appearance stability, its mechanical properties cannot be guaranteed.

[0101] As can be seen from Examples 7 and 8, when the amount added is constant, selecting coordinated thiol methyltin can achieve better thermal retention stability and lower color difference value of the product.

[0102] On the other hand, as can be seen from Examples 1, 9 and 10, when selecting maleimide derivatives, N-phenyl-substituted maleimides are preferred, which can further improve the appearance stability of the product under hot working environment while maintaining a high level of impact resistance.

[0103] As can be seen from the products in Examples 1 and 4-6, the degree of polymerization of the PVC matrix resin in the product also affects the processing performance of the product. When a PVC resin with a moderate degree of polymerization is selected, the thermal retention stability and impact resistance of the product can be maintained at a higher level.

[0104] In addition, as the main acid absorbent component, the particle size of calcium carbonate affects both its acid absorption and dispersion effects. As can be seen from Examples 1 and 11-13, the difference in these effects ultimately affects the product's impact resistance and thermal retention appearance stability. When the average particle size of the acid absorbent in the product components is preferably in the range of 2-3 μm, the overall performance of the product is better.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A PVC / ABS alloy, characterized in that, Includes the following components in parts by weight: 100 parts PVC resin, 5-50 parts ABS resin, 3-5 parts toughening agent, 3-5 parts methyltin mercaptan, 0.2-0.6 parts maleimide derivative, 3-8 parts acid scavenger, and 0.4-1 part antioxidant; The average degree of polymerization of the PVC resin is 400-750; the acid scavenger includes calcium carbonate and stearate; the mass ratio of calcium carbonate to stearate is 1:(0.05-0.2). The thiomethyltin includes coordinated thiomethyltin.

2. The PVC / ABS alloy as described in claim 1, characterized in that, The ABS resin, according to ISO 1133-2011, has a melt flow rate of 7~20 g / 10 min at 220°C and 10 kg load.

3. The PVC / ABS alloy as described in claim 1, characterized in that, The maleimide derivatives include at least one of N-substituted maleimide, alkyl-substituted maleimide, and phenyl-substituted maleimide.

4. The PVC / ABS alloy as described in claim 3, characterized in that, The maleimide derivatives include N-phenyl-substituted maleimides.

5. The PVC / ABS alloy as described in claim 1, characterized in that, The average particle size of the calcium carbonate is 1~5μm.

6. The PVC / ABS alloy as described in claim 5, characterized in that, The average particle size of the calcium carbonate is 2~3 μm.

7. The PVC / ABS alloy as described in claim 1, characterized in that, The toughening agent includes at least one of methyl methacrylate-acrylate copolymer, acrylonitrile-butyl acrylate-styrene terpolymer, and chlorinated polyethylene.

8. The method for preparing the PVC / ABS alloy according to any one of claims 1 to 7, characterized in that, Includes the following steps: The components other than the toughening agent are heated to 90~100℃ and mixed evenly. Then the toughening agent is added and mixed evenly. After cooling to 75~80℃, the mixture is placed in a screw extruder for melt extrusion and granulation to obtain the PVC / ABS alloy.

9. An electronic appliance casing, characterized in that, Includes the PVC / ABS alloy described in any one of claims 1 to 7.

Images