Radiation-resistant agent for PVC (polyvinyl chloride) resin as well as preparation method and application of radiation-resistant agent

Abstract

The invention discloses an irradiation-resistant agent for PVC (polyvinyl chloride) resin as well as a preparation method and application of the irradiation-resistant agent, and the preparation method comprises the following steps: 1) mixing silicone oil, a surfactant, a metal oxide, a catalyst, water and hydrotalcite, and heating for reaction to obtain a component A; and 2) uniformly mixing an antioxidant, beta-diketone, the component A in the step 1) and an optional additive to obtain the irradiation-resistant agent for the PVC resin. According to the radiation-resistant agent for the PVC resin, the component A is introduced, so that the radiation-resistant agent has certain radiation resistance while assisting stabilization, the prepared radiation-resistant agent for the PVC resin has multiple functions of terminating free radicals, absorbing radiation rays, reducing peroxides, replacing unstable structures, absorbing hydrogen chloride and the like, the full-scene application requirements in the polymerization, post-processing and radiation sterilization processes are ensured, and the radiation-resistant agent for the PVC resin has wide application prospects. The problems of yellowing and fogging caused by PVC irradiation are solved in the whole process.

Description

Technical Field

[0001] The present invention relates to the technical field of radiation-resistant agents, and in particular to a radiation-resistant agent for PVC resin, a preparation method and an application thereof. Background Art

[0002] Polyvinyl chloride (PVC) is one of the five most common thermoplastic resins. PVC boasts advantages such as high strength, corrosion resistance, flame retardancy, and excellent chemical resistance. It is widely used in various fields, including manufacturing, construction, and agriculture. In particular, it is one of the most consumed plastics in disposable medical supplies. Since medical devices come into direct or indirect contact with the human body, sterilization is extremely important, ensuring that no microorganisms survive. Traditional ethylene oxide sterilization methods pose risks of environmental pollution and the risk of drug residues on medical devices that endanger human health. Radiation sterilization of PVC packaging materials and medical devices using gamma rays or high-energy electron beams has attracted considerable attention due to its high efficiency, safety, and absence of chemical residues. Irradiation sterilization is becoming increasingly popular in advanced countries for the disinfection of PVC medical devices. However, irradiation of PVC easily produces a large number of chromophores in the PVC molecular chains, causing severe yellowing, resulting in reduced whiteness and increased haze in the finished product, making it unsuitable for medical use.

[0003] Given the importance of radiation-resistant medical polyvinyl chloride (PVC), various solutions have been published both domestically and internationally to address this issue. For example, U.S. Patent Publication No. US2014 / 0162045 reduces the amount of calcium / zinc stabilizers and simultaneously adds a small amount of inorganic blue pigment to improve the radiation resistance of PVC. Chinese Patent Application Publication No. CN11149998A proposes using a combination of hindered phenols, phosphites, and amorphous calcium silicate to enhance the radiation resistance of PVC.

[0004] The above methods all solve the problem by adding auxiliary additives at the downstream processing end of PVC, and their reliability is generally good. At present, no special additives have been found that can effectively solve the problems of yellowing and fogging of PVC resin due to radiation. Therefore, providing a special radiation-resistant additive that can be used for PVC resin has become one of the technical problems that need to be solved in this field. Summary of the Invention

[0005] In view of this, the present invention provides a radiation resistant agent for PVC resin and a preparation method thereof. First, a surfactant, silicone oil, metal oxide and hydrotalcite are mixed and reacted to modify the PVC resin, and then the PVC resin is compounded with antioxidants and other components to prepare the radiation resistant agent.

[0006] The application also provides the application of the radiation-resistant agent for PVC resins in the PVC resins, which can significantly improve the radiation resistance of the PVC resins, provide good stability, ensure the application requirements of the PVC resins in the whole scene such as the polymerization end, the downstream processing end and the radiation sterilization process, play the roles of terminating free radicals, absorbing radiation rays, reducing peroxides, replacing unstable structures and absorbing hydrogen chloride, and solve the problems of radiation yellowing and fogging of the PVC resin products in the whole process.

[0007] In the first aspect of the application, a preparation method of a radiation-resistant agent for PVC resins is provided, and the steps include:

[0008] 1) mixing silicon oil, a surfactant, a metal oxide, a catalyst, water and hydrotalcite, and heating to react to obtain component A;

[0009] 2) uniformly mixing an antioxidant, a beta-diketone, the component A of step 1) and optional additives to obtain the radiation-resistant agent for PVC resins.

[0010] In an embodiment, the silicon oil in step 1) is at least one selected from methyl silicon oil and ethyl silicon oil, for example, at least one selected from dimethyl silicon oil and diethyl silicon oil, and the hydrotalcite modified by the silicon oil has the effects of reducing the surface tension and improving the dispersibility in the system.

[0011] In an embodiment, the surfactant in step 1) mainly plays the role of strengthening the dispersing effect, and there is no special requirement for the type thereof, which can be a conventional type selected in the field; alternatively, the surfactant is at least one selected from cetyltrimethylammonium bromide (CTAB), polyvinyl alcohol (PVA) and cellulose.

[0012] In an embodiment, the metal oxide in step 1) can play the role of enhancing the light shielding effect of the hydrotalcite, and the metal is at least one selected from Fe, Zn, Ce and Ti;

[0013] Alternatively, the metal oxide is at least one selected from zinc oxide, titanium dioxide and cerium oxide;

[0014] Alternatively, the particle size of the metal oxide is ≤1 um, for example, nano metal oxide, and the particle size range can make the downstream product have better transparency, including but not limited to 1 um, 950 nm, 900 nm, 850 nm, 800 nm, 700 nm, 600 nm, 500 nm, 300 nm, 100 nm, 50 nm, 10 nm or a range between any two of them.

[0015] In an embodiment, the catalyst of step 1) is selected from at least one of an alkali metal hydroxide, an alkaline earth metal hydroxide, for example, at least one of sodium hydroxide, potassium hydroxide, calcium hydroxide, and the like.

[0016] In an embodiment, the hydrotalcite of step 1) is selected from at least one of a binary hydrotalcite, a ternary hydrotalcite;

[0017] The binary hydrotalcite is composed of two metal cations, typically a combination of one divalent metal cation and one trivalent metal cation, optionally, the metal ions of the binary hydrotalcite in the present application are selected from a combination of any two of magnesium ion, aluminum ion, zinc ion, nickel ion, for example, Mg-Al binary hydrotalcite, Zn-Al binary hydrotalcite, and the like.

[0018] The ternary hydrotalcite contains three metal cations, typically a combination of two divalent metal cations and one trivalent metal cation, optionally, the metal ions of the ternary hydrotalcite in the present application are selected from a combination of any three of magnesium ion, aluminum ion, zinc ion, copper ion, nickel ion, and the like, for example, Zn-Mg-Al ternary hydrotalcite, Ni-Mg-Al ternary hydrotalcite, and the like.

[0019] In an embodiment, the amount of the surfactant of step 1) is 1.7-4.2% by mass of the silicone oil, including but not limited to 1.7%, 2.0%, 2.3%, 2.7%, 3.0%, 3.3%, 3.7%, 4.0%, 4.2%, or a range consisting of any two of them.

[0020] In an embodiment, the amount of the metal oxide of step 1) is 2.7-4.2% by mass of the silicone oil, including but not limited to 2.7%, 3.0%, 3.2%, 3.4%, 3.6%, 3.8%, 4.0%, 4.2%, or a range consisting of any two of them.

[0021] In an embodiment, the amount of the catalyst of step 1) is 1.7-3.3% by mass of the silicone oil, including but not limited to 1.7%, 2.0%, 2.2%, 2.4%, 2.6%, 2.8%, 3.0%, 3.3%, or a range consisting of any two of them.

[0022] In an embodiment, the amount of the hydrotalcite of step 1) is 8.3-13.8% by mass of the silicone oil, including but not limited to 8.3%, 9.0%, 10.0%, 11.0%, 12.0%, 13.0%, 13.8%, or a range consisting of any two of them.

[0023] In one embodiment, the amount of water in step 1) is more than 40% of the mass of the silicone oil, preferably 40-100%, including but not limited to 40%, 60%, 80%, 100%, 150%, 200%, 300%, 400%, 500%, etc. or a range composed of any two thereof.

[0024] In one embodiment, the mixing in step 1) includes a constant temperature stirring process, the constant temperature stirring temperature is 100-150° C., and the time is 0.5-1 h; specifically, the constant temperature stirring temperature includes but is not limited to 100° C., 110° C., 120° C., 130° C., 140° C., 150° C. or a range between any two thereof, and the time includes but is not limited to 0.5 h, 0.6 h, 0.7 h, 0.8 h, 0.9 h, 1 h or a range between any two thereof;

[0025] Optionally, the stirring speed is 200-300 r / min, including but not limited to 200 r / min, 220 r / min, 240 r / min, 260 r / min, 280 r / min, 300 r / min or a range between any two thereof.

[0026] In one embodiment, the reaction temperature in step 1) is 100-150°C, and the reaction time is 2-4h; specifically, the temperature includes but is not limited to 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C,

[0027] 140℃, 145℃, 150℃ or any range between them, the time is but not limited to 2h, 2.3h,

[0028] 2.5h, 2.7h, 3h, 3.3h, 3.5h, 3.7h, 4h or a range between any two of them.

[0029] In some optional examples, the specific operations of step 1) include:

[0030] mixing water and a catalyst to form a catalyst solution;

[0031] Stir the silicone oil and surfactant evenly, then add the hydrotalcite and metal oxide, and simultaneously add the catalyst solution dropwise, stirring at a constant temperature to obtain a mixed solution;

[0032] The mixed solution is heated to react, and then cooled to obtain component A.

[0033] In step 1) of the present invention, component A is obtained by a hydrothermal reaction between a surfactant, silicone oil, and a metal oxide. The properties of the hydrotalcite and the metal oxide treated in this manner are both improved. Specifically, silicone oil modification can reduce surface tension and enhance dispersibility, while also imparting radiation resistance to the hydrotalcite and helping to enhance the shielding ability of the metal oxide against radiation. The synergistic effect of these components can improve the appearance stability of the PVC resin material after irradiation. In an irradiated environment, the interlayer structure of the hydrotalcite can adsorb and stabilize free radicals, while the metal oxide further scavenges free radicals through redox reactions. The synergistic effect of the two can also reduce the risk of radiation-induced rupture of the PVC resin molecular chain, thereby ensuring the stability of the main chain.

[0034] In one embodiment, the raw materials in step 2) include, by weight:

[0035] Component A 30-60 parts;

[0036] 0.01-0.5 parts of antioxidant;

[0037] 0.01-0.5 parts of β-diketone;

[0038] Additives 0-125 parts.

[0039] In detail, in the raw materials of step 2), in parts by weight, the component A includes but is not limited to 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts or a range consisting of any two thereof; the antioxidant includes but is not limited to 0.01 part, 0.05 part, 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part or a range consisting of any two thereof; the β-diketone includes but is not limited to 0.01 part, 0.05 part, 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part or a range consisting of any two thereof; the additive includes but is not limited to 0 part, 0.1 part, 1 part, 10 parts, 25 parts, 50 parts, 75 parts, 100 parts, 125 parts or a range consisting of any two thereof.

[0040] In one embodiment, the antioxidant in step 2) can be a conventional type selected in the field, and there is no special requirement for its type. For example, the antioxidant is selected from at least one of hindered amines, phosphites, hindered phenols, thioesters, etc.

[0041] Optionally, the antioxidant is selected from at least one of antioxidant 245, antioxidant 1076, antioxidant 1010, etc.

[0042] In one embodiment, the β-diketone in step 2) is a compound having a structure in which two ketone groups are separated by one carbon atom (i.e., β-position), for example, at least one selected from stearoylbenzoylmethane (SBM), octanoylbenzoylmethane (OBM), dibenzoylmethane (DBM), etc.

[0043] In one embodiment, the additive in step 2) is selected from at least one of conventional adjuvants, such as emulsifiers, thickeners, dispersants, terminators, etc.;

[0044] Optionally, the additive includes an emulsifier. The specific type of the emulsifier is not limited and can be conventionally selected in the field, for example, at least one selected from Span60, Span80, Tween60, Tween80, etc.; Optionally, the amount of the emulsifier used, in parts by weight, is 0.5-1 part, including but not limited to 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part, 1 part, or a range consisting of any two parts thereof;

[0045] Optionally, the additive includes a thickener. The specific type of the thickener is not limited and can be conventionally selected in the field, for example, at least one selected from hydroxypropyl methylcellulose (HPMC), polyethylene glycol (PEG), etc.; Optionally, the amount of the thickener is 0.5-1 part by weight, including but not limited to 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part, 1 part or a range composed of any two parts thereof.

[0046] In one embodiment, the additive in step 2) further includes water, to obtain a radiation-resistant agent product of an aqueous phase system;

[0047] Optionally, the amount of water used is 100-120 parts by weight, including but not limited to 100 parts, 105 parts, 110 parts, 115 parts, 120 parts or any range between two parts.

[0048] In one embodiment, step 2) the mixing includes a constant temperature stirring process, the constant temperature stirring temperature is 70-90 ° C, the time is 0.2-1h; specifically, the constant temperature stirring temperature includes but is not limited to 70 ° C, 73 ° C, 77 ° C, 80 ° C, 83 ° C, 87 ° C, 90 ° C or any range between two thereof, and the time is but is not limited to 0.2h, 0.4h,

[0049] 0.6h, 0.8h, 1h or a range between any two of them;

[0050] Optionally, the stirring speed is 200-300 r / min, including but not limited to 200 r / min, 220 r / min, 240 r / min, 260 r / min, 280 r / min, 300 r / min or a range between any two thereof.

[0051] In some optional examples, the specific operation of step 2) includes: mixing and stirring the optional additive components (such as water, emulsifier, thickener, etc.) for a certain period of time at the mixing temperature to obtain a uniform solution, and then adding component A, β-diketone, and antioxidant and continuing to stir uniformly at a constant temperature. After cooling, the radiation-resistant agent for PVC resin can be obtained.

[0052] In a second aspect of the present invention, a radiation-resistant agent for PVC resin is provided. The radiation-resistant agent is prepared by the preparation method described above.

[0053] In step 2) described above, the β-diketone, antioxidant, component A, and optional additives are mixed to obtain a radiation-resistant agent composition for PVC resin. Specifically, during use, the antioxidant component can terminate the reaction during the polymerization of the PVC resin, inhibit oxidation during processing, and scavenge secondary free radicals generated by irradiation during irradiation. Furthermore, the antioxidant can synergize with the metal oxide to reduce damage to the main chain of the PVC resin, maintain long-term stability, and improve the mechanical properties of the product. The antioxidant can also synergize with the hydrotalcite to decompose peroxides generated by irradiation, maintaining stability during processing. Furthermore, the β-diketone and the hydrotalcite can synergize to displace unstable structures and absorb hydrogen chloride, thereby improving initial stability.

[0054] In a third aspect of the present invention, there is provided a use of the radiation resistance agent for PVC resin.

[0055] The radiation-resistant agent for PVC resin of the present invention can be used in any stage related to the production and processing of PVC resin, such as the polymerization end and the downstream processing end, and can solve the radiation yellowing and fogging problems of PVC resin products in the whole process. The radiation-resistant agent of the present invention is applied at the polymerization end, for example, when the polymerization conversion rate of raw materials such as vinyl chloride monomer reaches 70-90%, it is added to the polymerization system to obtain PVC resin with excellent radiation resistance and good stability, which can ensure that the radiation yellowing and fogging problems in the whole process such as polymerization, post-processing, and radiation sterilization can be solved. The radiation-resistant agent of the present invention is applied at the downstream processing end of PVC, such as when it is introduced into the modification system of PVC resin raw materials, and can also solve the radiation yellowing and fogging problems in post-processing and radiation sterilization.

[0056] In some optional examples, the radiation-resistant agent for PVC resin is used in the preparation process of PVC resin;

[0057] Specifically, the application is in the preparation process of PVC resin, when the polymerization conversion rate reaches 70-90%, including but not limited to 70%, 73%, 77%, 80%, 83%, 87%, 90% or a range consisting of any two of them, the PVC resin is added with a radiation resistant agent to the reaction kettle for continuous polymerization to obtain a radiation resistant PVC resin.

[0058] The preparation process of the PVC resin has no special requirements and can be any preparation method known in the prior art, for example, prepared from vinyl chloride through a free radical polymerization system (suspension polymerization, emulsion polymerization, bulk polymerization, etc.). In actual applications, the methods disclosed in US4469852A, CN104693309B, etc. can be referred to. For related operations and process conditions in these preparation methods, and the devices used, the corresponding conventional choices in the art can be used, and there is no special limitation. The skilled person can optimize according to actual needs based on the known processes in the prior art, and the present application will not be described here.

[0059] Optionally, the PVC resin is added with a radiation resistant agent in an amount of 0.1-0.5% of the mass of vinyl chloride monomer, including but not limited to 0.1%, 0.2%, 0.3%, 0.4%, 0.5% or a range consisting of any two of them.

[0060] In some optional examples, the radiation resistant agent for PVC resin is applied in the modification process of PVC resin.

[0061] Specifically, the application is in the downstream processing, blending modification, etc. of PVC resin, the radiation resistant agent for PVC resin, the PVC resin raw material, and other components are combined for use, and then processed by heat mixing, extrusion, etc. to obtain a modified PVC resin with radiation resistance.

[0062] The processing method of the PVC resin has no special requirements and can be any processing, modification method known in the prior art, for example, blending, granulation, calendering, injection molding, etc. In actual applications, the methods disclosed in CN112480548A, etc. can be referred to. For related operations and process conditions in these methods, and the devices used, the corresponding conventional choices in the art can be used, and there is no special limitation. The skilled person can optimize according to actual needs based on the known processes in the prior art, and the present application will not be described here.

[0063] Optionally, the PVC resin is added with a radiation resistant agent in an amount of 0.5-2% of the mass of the PVC resin raw material, including but not limited to 0.5%, 0.7%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2% or a range consisting of any two of them.

[0064] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0065] The radiation-resistant agent for PVC resin prepared by the present invention has many functions such as terminating free radicals, absorbing radiation, reducing peroxides, replacing unstable structures, and absorbing hydrogen chloride, ensuring full-scene application requirements during polymerization, post-processing, and radiation sterilization, and solving the problems of yellowing and fogging of PVC due to radiation from the entire process. DETAILED DESCRIPTION

[0066] In order to facilitate the understanding of the present invention, the present invention will be further described below in conjunction with examples. It should be understood that the following examples are only for a better understanding of the present invention and do not mean that the present invention is limited to the following examples.

[0067] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. The term "and / or" as may be used herein includes any and all combinations of one or more of the associated listed items.

[0068] In the examples and comparative examples of the present invention, the sources of the main raw materials used are as follows. Unless otherwise specified, other raw materials and reagents were purchased from commercial sources:

[0069] Silicone oil: dimethyl silicone oil and diethyl silicone oil were from Aladdin Reagent Company;

[0070] Surfactant: Sodium dodecylbenzenesulfonate (SDBS) was from Aladdin Reagent Company;

[0071] Metal oxides: titanium dioxide (particle size ≤ 1 μm), zinc oxide (particle size ≤ 1 μm), and cerium oxide (particle size ≤ 1 μm) were obtained from Aladdin Reagents.

[0072] Catalysts: Potassium hydroxide and calcium hydroxide were from Aladdin Reagent Company;

[0073] Hydrotalcite: 202 (binary hydrotalcite), 390 (ternary hydrotalcite), and 320 (binary hydrotalcite) were obtained from Ivy New Materials (Nanjing) Co., Ltd.

[0074] Antioxidants: 245, 1010, and 1076 are all from Tianjin Guolong New Material Technology Co., Ltd.

[0075] β-Diketone: SBM, DBM, and OBM were all from Shandong Jianbang New Materials Co., Ltd.;

[0076] Emulsifiers: Span60, Span80, Tween60, and Tween80 were from Beijing Inokai Reagent Co., Ltd.

[0077] Thickeners: cetyltrimethylammonium bromide (CTAB), HPMC, and PVA (B72) were from Beijing Inokai Reagent Co., Ltd.

[0078] Polyvinyl chloride resin: PVC WH-1000F is from Wanhua Chemical Group Co., Ltd.

[0079] Hereinafter, the radiation-resistant agent for PVC resin provided by the present invention will be described in detail through specific examples.

[0080] Example 1

[0081] Preparation of radiation-resistant agent 1 for PVC resin, the steps are:

[0082] 1) Add 50g of deionized water to a 200ml beaker to prepare a 4% (mass fraction) GaOH solution.

[0083] Place a three-necked flask in an oil bath at 110°C, add 120 g of dimethyl silicone oil and 2 g of surfactant CTAB and stir evenly, slowly add 10 g of hydrotalcite 201 and 3 g of zinc oxide while stirring at a speed of 200-300 r / min, and simultaneously add dropwise the above-mentioned CaOH solution (2 g of GaOH) and stir at constant temperature for 0.5 h to obtain a mixed solution;

[0084] The mixed solution was transferred to a hydrothermal reactor and reacted at 110°C for 2 h, and then cooled to room temperature to obtain a translucent milky white viscous liquid, namely component A1;

[0085] 2) Add 100 g of water, 0.25 g of emulsifier Span 60, 0.25 g of Tween 80, and 0.5 g of thickener HPMC into a three-necked flask and stir at 70° C. for 1 h to obtain an additive mixture at a stirring speed of 200-300 r / min;

[0086] To the above additive mixture, 0.01 g of antioxidant 1010, 0.01 g of SBM, and 130 g of component A from step 1) were added, and the mixture was stirred at 70° C. for 0.2 h, and then cooled to obtain radiation-resistant agent 1 for PVC resin.

[0087] Example 2

[0088] Preparation of radiation-resistant agent 2 for PVC resin, the steps are:

[0089] 1) Add 75g of deionized water to a 200ml beaker to prepare a 4% (mass fraction) NaOH solution.

[0090] Place a three-necked flask in an oil bath at 130°C, add 120 g of dimethyl silicone oil and 3 g of surfactant CTAB and stir evenly, slowly add 13.5 g of hydrotalcite 202 and 4 g of zinc oxide while stirring at a speed of 200-300 r / min, and simultaneously add dropwise the above-mentioned NaOH solution (3 g of NaOH) and stir at constant temperature for 0.8 h to obtain a mixed solution;

[0091] The mixed solution was transferred to a hydrothermal reactor and reacted at 130°C for 3 h, and then cooled to room temperature to obtain a translucent milky white viscous liquid, namely component A2;

[0092] 2) Add 110 g of water, 0.54 g of emulsifier Span 60, 0.26 g of Tween 80, and 0.8 g of thickener PEG into a three-necked flask and stir at 80° C. for 2 h to obtain an additive mixture at a stirring speed of 200-300 rpm;

[0093] To the above additive mixture, 0.2 g of antioxidant 245, 0.1 g of DBM, and 45 g of component A2 from step 1) were added, and the mixture was stirred at 80° C. for 0.5 h, then cooled to obtain radiation-resistant agent 2 for PVC resin.

[0094] Example 3

[0095] Preparation of radiation-resistant agent 3 for PVC resin, the steps are:

[0096] 1) Add 100g of deionized water to a 200ml beaker to prepare a 4% (mass fraction) KOH solution.

[0097] Place a three-necked flask in an oil bath at 150°C, add 120 g of dimethyl silicone oil and 4 g of PVA surfactant and stir evenly, slowly add 16.5 g of hydrotalcite 320 and 5 g of titanium dioxide while stirring at a speed of 200-300 r / min, and simultaneously add dropwise the above-mentioned KOH solution (4 g of KOH) and stir at constant temperature for 1 h to obtain a mixed solution;

[0098] The mixed solution was transferred to a hydrothermal reactor and reacted at 150°C for 4 h, and then cooled to room temperature to obtain a translucent milky white viscous liquid, namely component A3;

[0099] 2) Add 120 g of water, 0.75 g of emulsifier Span 80, 0.25 g of Tween 60, and 0.8 g of thickener HPMC into a three-necked flask and stir at 90° C. for 3 h to obtain an additive mixture at a stirring speed of 200-300 r / min;

[0100] To the above additive mixture, 0.5 g of antioxidant 1076, 0.2 g of OBM, and 55 g of component A3 from step 1) were added, and the mixture was stirred at 90° C. for 0.8 h, then cooled to obtain radiation-resistant agent 3 for PVC resin.

[0101] Example 4

[0102] Preparation of radiation-resistant agent 4 for PVC resin, the steps are:

[0103] 1) Add 75g of deionized water to a 200ml beaker to prepare a 4% (mass fraction) NaOH solution.

[0104] Place a three-necked flask in an oil bath at 130°C, add 120 g of dimethyl silicone oil and 5 g of surfactant PEG and stir evenly, slowly add 13.5 g of hydrotalcite 202 and 4 g of cerium oxide while stirring at a speed of 200-300 r / min, and simultaneously add dropwise the above-mentioned NaOH solution (3 g of NaOH) and stir at constant temperature for 0.5 h to obtain a mixed solution;

[0105] The mixed solution was transferred to a hydrothermal reactor and reacted at 140°C for 3 h, and then cooled to room temperature to obtain a translucent milky white viscous liquid, namely component A4;

[0106] 2) Add 105 g of water, 0.4 g of emulsifiers Span 60 and Tween 60, and 0.5 g of thickener PEGA into a three-necked flask and stir at 80° C. for 2 h to obtain an additive mixture at a stirring speed of 200-300 rpm;

[0107] To the above additive mixture, 0.2 g of antioxidant 245, 0.3 g of SBM, and 60 g of component A4 from step 1) were added, and the mixture was stirred at 90° C. for 1 h, and then cooled to obtain radiation-resistant agent 4 for PVC resin.

[0108] Example 5

[0109] Preparation of radiation-resistant agent 5 for PVC resin, the steps are:

[0110] 1) Add 75g of deionized water to a 200ml beaker to prepare a 4% (mass fraction) NaOH solution.

[0111] Place a three-necked flask in an oil bath at 140°C, add 120 g of diethyl silicone oil and 3 g of surfactant CTAB and stir evenly, slowly add 14.5 g of hydrotalcite 202 and 4 g of zinc oxide while stirring at a speed of 200-300 r / min, and simultaneously add dropwise the above-mentioned NaOH solution (3 g of NaOH) and stir at constant temperature for 1 h to obtain a mixed solution;

[0112] The mixed solution was transferred to a hydrothermal reactor and reacted at 130°C for 4 h, and then cooled to room temperature to obtain a translucent milky white viscous liquid, namely component A5;

[0113] 2) Add 110 g of water, 0.34 g of emulsifier Span 60, 0.16 g of Tween 80, and 1 g of thickener PEG into a three-necked flask and stir at 80° C. for 1 h to obtain an additive mixture at a stirring speed of 200-300 r / min;

[0114] To the above additive mixture, 0.1 g of antioxidant 245, 0.5 g of DBM, and 40 g of component A5 from step 1) were added, and the mixture was stirred at 80° C. for 0.5 h, and then cooled to obtain radiation-resistant agent 5 for PVC resin.

[0115] Comparative Example 1

[0116] The radiation resistant agent was prepared by referring to the method of Example 1, except that step 1) component A1 was omitted, that is, step 2) was directly used without adding component A1 to prepare radiation resistant agent 6.

[0117] Comparative Example 2

[0118] The radiation-resistant agent was prepared by referring to the method of Example 1, except that no antioxidant was added in step 2), and other operations and conditions remained unchanged, to obtain radiation-resistant agent 7.

[0119] Comparative Example 3

[0120] The radiation-resistant agent was prepared by referring to the method of Example 1, except that β-diketone SBM was not added in step 2). Other operations and conditions remained unchanged, and the radiation-resistant agent 8 was prepared.

[0121] Application performance evaluation

[0122] 1) The radiation-resistant agent for PVC resin is used in the preparation process of PVC resin. The preparation process refers to the method disclosed in patent US4469852A, and the radiation-resistant agents 1-5 for PVC resin prepared in Examples 1-5 of the present invention and the radiation-resistant agents 6-8 prepared in Comparative Examples 1-3 are added to the polymerization reaction system respectively.

[0123] The specific steps are as follows: using a 5L small-scale polymerization reactor, according to a formulation with a polymerization degree of 1000, a reaction temperature of 57.3°C, and when the polymerization reaction conversion rate is 80%, adding a radiation-resistant agent in an amount of 0.15% of the mass of the vinyl chloride monomer; after the reaction is completed, the discharged material is stripped, centrifuged, and dried to obtain a radiation-resistant PVC resin.

[0124] Comparative Example 4

[0125] Referring to the above steps, except that no radiation-resistant agent was added and other operations and conditions remained unchanged, ordinary PVC resin was prepared as a comparison sample (blank sample).

[0126] The following analytical method was used to test the properties of the radiation-resistant PVC resin prepared by the above method. The test results are shown in Table 1.

[0127] 1. Open refining whiteness and haze:

[0128] Evaluation formula: 30g radiation-resistant PVC resin, 12g dioctyl phthalate, 0.3g calcium stearate, 0.3g zinc stearate;

[0129] Evaluation conditions: temperature 190℃; sampling after 5 minutes of refining; sample thickness 0.4mm.

[0130] Evaluation equipment: double-roll mill; whiteness meter; haze meter.

[0131] 2. Whiteness and haze after irradiation thermal aging:

[0132] Irradiation conditions: irradiation intensity 30kGy; damp heat aging conditions: 60℃, humidity 60%, time 3000h.

[0133] Table 1 Performance test results of PVC resin prepared in Examples and Comparative Examples

[0134]

[0135] 2) The radiation-resistant agent for PVC resin is used in the blending modification of PVC resin. The modification process refers to the method disclosed in Example 1 of patent CN112480548A, and the radiation-resistant agents 1-5 for PVC resin prepared in Examples 1-5 of the present invention and the radiation-resistant agents 6-8 prepared in Comparative Examples 1-3 are added to the system respectively.

[0136] The specific steps are as follows: 1) PVC resin raw material (Wanhua Chemical Group Co., Ltd., polymerization degree 1000 resin)

[0137] 1) Add 100g of PVC, 1g of radiation-resistant agent (added amount is 1% of the mass of PVC resin raw material), 60g of plasticizer (DINCH BASF Co., Ltd.), 0.3g of lubricant (617 Honeywell China Co., Ltd.) and other additives into a high mixing pot, mix at 110°C for 10 min, and cool to 45°C for use; 2) add the cooled mixture into an extrusion granulator and extrude and granulate at 145°C to obtain radiation-resistant PVC pellets.

[0138] Comparative Example 5

[0139] With reference to the above steps, except that no radiation-resistant agent was added and other operations and conditions remained unchanged, ordinary PVC pellets were prepared as a comparison sample (blank sample).

[0140] The properties of the PVC modified resin were tested using the same analytical method as above. The test results are shown in Table 2.

[0141] Table 2 Performance test results of PVC pellets prepared in Examples and Comparative Examples

[0142]

[0143]

[0144] It will be readily understood that the above embodiments are merely examples for clarity of description and are not intended to limit the present invention to these examples. Those skilled in the art will readily appreciate that other variations or modifications based on the above description are possible. It is not necessary and impossible to provide an exhaustive list of all possible implementations. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for preparing a radiation-resistant agent for PVC resin, characterized in that the steps include: 1) mixing silicone oil, a surfactant, a metal oxide, a catalyst, water and hydrotalcite, and heating to react to obtain component A; 2) Evenly mixing the antioxidant, β-diketone, component A of step 1), and optional additives to obtain a radiation-resistant agent for PVC resin.

2. The preparation method according to claim 1, characterized in that Step 1) The silicone oil is selected from at least one of methyl silicone oil and ethyl silicone oil; and / or Step 1) the surfactant is selected from at least one of cetyltrimethylammonium bromide, polyethylene glycol, polyvinyl alcohol, and cellulose; and / or Step 1) The metal in the metal oxide is selected from at least one of Fe, Zn, Ce, and Ti; optionally, the metal oxide is selected from at least one of zinc oxide, titanium dioxide, and cerium oxide; Optionally, the particle size of the metal oxide is ≤1 μm; and / or Step 1) The catalyst is selected from at least one of alkali metal hydroxides and alkaline earth metal hydroxides, preferably at least one of sodium hydroxide, potassium hydroxide and calcium hydroxide; and / or In step 1), the hydrotalcite is selected from at least one of binary hydrotalcite and ternary hydrotalcite.

3. The preparation method according to claim 1 or 2, characterized in that Step 1) The amount of the surfactant is 1.7-4.2% of the mass of the silicone oil; and / or Step 1) The amount of the metal oxide is 2.7-4.2% of the mass of the silicone oil; and / or The amount of the catalyst in step 1) is 1.7-3.3% of the mass of the silicone oil; and / or Step 1) The amount of hydrotalcite used is 8.3-13.8% of the mass of silicone oil; and / or The amount of water used in step 1) is more than 40% of the mass of the silicone oil, preferably 40-100%.

4. The preparation method according to any one of claims 1 to 3, characterized in that Step 1) the mixing includes a constant temperature stirring process, the constant temperature stirring temperature is 100-150 ° C, the time is 0.5-1h; and / or The reaction temperature of step 1) is 100-150° C., and the reaction time is 2-4 h.

5. The preparation method according to any one of claims 1 to 4, characterized in that The raw materials in step 2) include, by weight: Component A 30-60 parts; 0.01-0.5 parts of antioxidant; 0.01-0.5 parts of β-diketone; Additives 0-125 parts.

6. The preparation method according to any one of claims 1 to 5, characterized in that Step 2) the antioxidant is selected from at least one of hindered amines, phosphites, hindered phenols, and thioester antioxidants; Optionally, the antioxidant is selected from at least one of antioxidant 245, antioxidant 1076, and antioxidant 1010; and / or Step 2) the β-diketone is selected from at least one of stearoylbenzoylmethane, octanoylbenzoylmethane, and dibenzoylmethane; and / or Step 2) the additive is selected from at least one of an emulsifier, a thickener, a dispersant, and a terminator; Optionally, the amount of the emulsifier is 0.5-1 parts by weight; Optionally, the amount of the thickener is 0.5-1 parts by weight; and / or Step 2) the additive includes water; Optionally, the amount of water used is 100-120 parts by weight.

7. The preparation method according to any one of claims 1 to 6, characterized in that Step 2) The mixing includes a constant temperature stirring process, the constant temperature stirring temperature is 70-90° C., and the time is 0.2-1 h.

8. A radiation-resistant agent for PVC resin, characterized in that: The radiation-resistant agent is prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the radiation-resistant agent for PVC resin prepared by the preparation method according to any one of claims 1 to 7 or the radiation-resistant agent for PVC resin according to claim 8 as a radiation-resistant agent for PVC resin; Optionally, it can be used in any stage related to the production process of PVC resin.

10. The use according to claim 9, characterized in that The radiation-resistant agent for PVC resin is used in the preparation process of PVC resin; optionally, the amount of the radiation-resistant agent for PVC resin added is 0.1-0.5% of the mass of vinyl chloride monomer; and / or The radiation-resistant agent for PVC resin is used in the modification process of PVC resin; optionally, the addition amount of the radiation-resistant agent for PVC resin is 0.5-2% of the mass of the PVC resin raw material.

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