Macromolecular resin composition as well as preparation method and application thereof

Abstract

The invention provides a polymer resin composition as well as a preparation method and application thereof. The polymer resin composition is prepared from the following components in parts by weight: 100 parts of polymer resin and 0.05 to 0.5 part of p-hydroxybenzoic acid derivative. Wherein the p-hydroxybenzoic acid derivative is used as an anti-radiation auxiliary agent and can be matched with various medical polymer resin materials for use. Meanwhile, tests show that after being irradiated by electron beams, a plurality of different polymer resin compositions prepared by the invention are low in yellowness index, which shows that the composition has excellent low-irradiation discoloration performance. Moreover, the polymer resin composition is high in tensile strength after being irradiated by electron beams, so that the polymer resin composition still has excellent mechanical properties after being irradiated.

Description

Technical Field

[0001] The invention belongs to the technical field of biomedical materials, and specifically relates to a polymer resin composition and a preparation method and application thereof. Background Art

[0002] In recent years, irradiation sterilization, especially electron beam irradiation sterilization, has been increasingly applied to the sterilization of disposable medical devices due to its advantages of high efficiency, thorough sterilization, no residue, and immediate use after sterilization. According to statistics, more than 50% of medical devices worldwide have adopted irradiation sterilization, and the proportion is still on the rise, and it will soon develop into the mainstream sterilization technology for medical devices.

[0003] However, when irradiated, the polymer materials used to make medical devices are bombarded by high-energy rays, generating a large number of active free radicals on their molecular chains. These active free radicals will undergo complex free radical chemical reactions and will undergo slow, long-lasting chain oxidative degradation reactions with oxygen (i.e., rapid aging), resulting in a decrease in the physical and mechanical properties of the polymer materials, changes in their chemical and biological properties, and a yellowing or even redding of the color, which seriously affects the product's appearance, storage life, and performance.

[0004] Based on this, researchers have disclosed many solutions, the main method of which is to add some additives with antioxidant ability to medical polymer materials. For example, the US patent with publication number US7053139 points out that the use of phthalide and its derivatives can reduce the yellowness index of polyvinyl chloride after irradiation. Patent CN102827437A proposes to use hindered phenols and phosphites to increase the radiation resistance of polyvinyl chloride. Patent CN202210397445.2 proposes that the combination of reactive hindered amines and hindered phenols can prepare medical-grade radiation-resistant polypropylene materials. Patent CN200910067231.3 proposes that reactive hindered amines increase the radiation aging resistance of polypropylene. Patent publication number WO 08238, 1997 mentions that blending 50-99 wt% homopolymer PP or copolymer PP and 1-50 wt% single-site catalyzed polyethylene can improve the radiation aging resistance of PP. This material can be used for medical materials, but this method is not suitable for polymer materials other than polypropylene.

[0005] It can be seen that although many solutions have been disclosed in this field, the solutions mentioned are usually only applicable to specific materials or cases. For example, hindered amines can be used in polyolefins, but polyvinyl chloride added with hindered amines undergoes a significant reddening phenomenon after irradiation; for example, the combination of reactive hindered phenols and hindered amines can significantly improve the radiation resistance of polypropylene, but this type of anti-radiation additive is difficult to use in polyvinyl chloride and polyester materials, and the cost is relatively high.

[0006] In summary, the existing technology still lacks universality, and the development of widely applicable anti-radiation additives to improve the radiation resistance of medical polymer raw materials still has important application value. Summary of the invention

[0007] In view of this, the object of the present invention is to provide a polymer resin composition and a preparation method and application thereof. The polymer resin composition has excellent radiation resistance.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a polymer resin composition, comprising, by weight, 100 parts of a polymer resin and 0.05 to 0.5 parts of a p-hydroxybenzoic acid derivative;

[0010] The structural formula of the p-hydroxybenzoic acid derivative is shown in Formula I:

[0011] Formula I;

[0012] Wherein, R1 is selected from H atom, methyl or tert-butyl;

[0013] R2 is selected from an alkoxy group having 8 or more carbon atoms, a polyol group or a polyamine group.

[0014] Preferably, the alkoxy group having 8 or more carbon atoms includes, but is not limited to, octyloxy, decyloxy, lauryloxy, hexadecyloxy, octadecyloxy or behenyloxy.

[0015] Preferably, the polyol group includes but is not limited to an ethylene glycol group, a propylene glycol group, a butylene glycol group, a hexanediol group, a decanediol group, a glycerol group, an ethanetrimethylol group, a propanetrimethylol group, a pentaerythritol group or a dipentaerythritol hexanol group.

[0016] Preferably, the polyamine group includes but is not limited to pentamethylenediamine, hexamethylenediamine, decanediamine or lauryldiamine.

[0017] Preferably, the p-hydroxybenzoic acid derivative is selected from any one or more of 3,5-di-tert-butyl-4-hydroxybenzoic acid octadecyl ester, 3,5-di-tert-butyl-4-hydroxybenzoic acid hexadecyl ester, di(3,5-di-tert-butyl-4-hydroxybenzoic acid)-triethylene glycol ester, tetrakis(3,5-di-tert-butyl-4-hydroxybenzoic acid) pentaerythritol ester, N,N'-bis-(3,5-di-tert-butyl-4-hydroxybenzoyl)hexanediamine, N,N'-bis-(3,5-di-tert-butyl-4-hydroxybenzoyl)pentanediamine and N,N'-bis-(3,5-di-tert-butyl-4-hydroxybenzoyl)decanediamine.

[0018] Preferably, the polymer resin is a medical polymer resin.

[0019] Preferably, the medical polymer resin includes but is not limited to polyethylene, copolymer polyethylene, ultra-high molecular weight polyethylene, polypropylene, copolymer polypropylene, polyvinyl chloride, polystyrene-polybutadiene-polystyrene, polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate-ethylene glycol-cyclohexanedimethanol copolymer polyester, polyethylene terephthalate-ethylene glycol-cyclohexanedimethanol ester, polyethylene terephthalate-ethylene glycol, polycarbonate resin, acrylonitrile-butadiene-styrene copolymer, nylon, nylon elastomer, polyester elastomer, styrene thermoplastic elastomer, polyolefin elastomer, butyl rubber, natural rubber or nitrile rubber.

[0020] Preferably, the polymer resin composition further comprises an antioxidant.

[0021] Preferably, the antioxidant includes but is not limited to phosphite antioxidants, thioether antioxidants, dihydropyridine antioxidants or amine antioxidants.

[0022] Preferably, the phosphite antioxidant includes but is not limited to tris[2.4-di-tert-butylphenyl]phosphite (antioxidant 168), pentaerythritol dioctadecyl diphosphite (antioxidant 618), bis[2,4-di-tert-butylphenol]pentaerythritol-diphosphite (antioxidant 626), bis(2,4-dicumylphenyl)pentaerythritol-diphosphite (antioxidant S9228), 4,4'-isopropyl diphenyl C12~14 alcohol phosphite (phosphite 1500), tris[dodecyl]phosphite, 4,4'-butylenebis-(3-methyl-6-tert-butylphenyl)-tetra(tridecyl) diphosphite (AS-4500).

[0023] Preferably, the dihydropyridine antioxidant includes but is not limited to 3,5-dihydropyridine dicarboxylate, 3,5-dihydropyridine dialkyl carboxylate or 2,6-dimethyl-1,4-dihydro-3,5-pyridine dicarboxylate dialkyl carboxylate.

[0024] Preferably, the amine antioxidant includes but is not limited to hindered amine antioxidants or oxidized amine antioxidants, and the hindered amine antioxidants include but are not limited to light stabilizer 292, light stabilizer 622, light stabilizer 770, light stabilizer 944, light stabilizer 2020, light stabilizer 3346, light stabilizer 3549, light stabilizer 3853, light stabilizer 4050 or light stabilizer 5050H.

[0025] Preferably, the amine oxide antioxidant includes but is not limited to bis(octadecyl)hydroxylamine and / or bis(octadecyl)amine oxide free radical.

[0026] Preferably, the polymer resin composition comprises, by weight, 100 parts of polymer resin, 0.05-0.5 parts of p-hydroxybenzoic acid derivatives, and 0.05-0.5 parts of antioxidants.

[0027] Preferably, the polymer resin composition further comprises a functional auxiliary agent.

[0028] Preferably, the functional auxiliary agent includes but is not limited to a nucleating agent, a mold release agent, a lubricant, a reinforcing filler, a radiographic filler or an acid absorbent.

[0029] In a second aspect, the present invention provides a method for preparing the above-mentioned polymer resin composition, comprising the following steps:

[0030] The polymer resin, the p-hydroxybenzoic acid derivative, the optional antioxidant and the optional functional auxiliary agent are mixed and then extruded to obtain a polymer resin composition.

[0031] In a third aspect, the present invention further provides a medical material, which includes the polymer resin composition involved in the above technical solution.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention provides a polymer resin composition, which comprises 100 parts of polymer resin and 0.05-0.5 parts of p-hydroxybenzoic acid derivatives by weight. The p-hydroxybenzoic acid derivatives can be used in combination with a variety of medical polymer resin materials as anti-radiation additives. At the same time, after testing, the various different polymer resin compositions prepared by the present invention have low yellowness index after electron beam irradiation, indicating that they have excellent low-irradiation color change performance. In addition, the polymer resin composition has high tensile strength after electron beam irradiation, indicating that it still has excellent mechanical properties after irradiation.

[0034] In summary, the present invention uses p-hydroxybenzoic acid derivatives as anti-radiation additives, which have the advantages of wide applicability and universality when applied to polymer resin materials, and the obtained composition has excellent performance. DETAILED DESCRIPTION

[0035] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] In view of the problem that the application range of the anti-radiation auxiliary agent in the prior art is narrow, the present invention provides an anti-radiation auxiliary agent applicable to a variety of polymer resin materials. The anti-radiation auxiliary agent is a para-hydroxybenzoic acid derivative, and its structural formula is shown in Formula I:

[0037] Formula I;

[0038] Wherein, R1 is selected from H atom, methyl or tert-butyl, preferably tert-butyl. It should be noted that in the present invention, if R1 is selected from other groups, such as ethyl, the anti-yellowing effect will be reduced.

[0039] In the present invention, R2 is selected from an alkoxy group having 8 or more carbon atoms, a polyol group or a polyamine group.

[0040] The present invention finds that the anti-radiation auxiliary agent has more outstanding yellowing resistance performance compared with the p-hydroxyphenylpropionic acid structure in the prior art.

[0041] In some embodiments of the present invention, the p-hydroxybenzoic acid derivative has a structure shown in Formula I, wherein when R2 is selected from an alkoxy group having more than 8 carbon atoms, the alkoxy group having more than 8 carbon atoms includes, but is not limited to, octyloxy, decyloxy, lauryloxy, hexadecyloxy, octadecyloxy, or docosyloxy. Generally, the larger the molecular weight of the R2 group, the better the high temperature volatility and extraction resistance, and the more suitable it is for polymer materials requiring higher processing temperatures. Exemplarily, the use of 3,5-di-tert-butyl-4-hydroxybenzoic acid octyl ester can well meet the processing temperature of polyvinyl chloride, and the use of 3,5-di-tert-butyl-4-hydroxybenzoic acid hexadecyl ester can be suitable for polymer resins with higher processing temperatures, such as polypropylene.

[0042] In some embodiments of the present invention, the p-hydroxybenzoic acid derivative has a structure shown in Formula I, wherein when R2 is selected from a polyol group, the polyol group includes but is not limited to ethylene glycol, propylene glycol, butylene glycol, hexanediol, decanediol, glycerol, ethanetrimethylol, propanetrimethylol, pentaerythritol or dipentaerythritol hexol, preferably pentaerythritol. Exemplarily, the p-hydroxybenzoic acid derivative can be pentaerythritol tetrakis-(3,5-di-tert-butyl-4-hydroxybenzoate).

[0043] In some embodiments of the present invention, the p-hydroxybenzoic acid derivative has a structure shown in Formula I, wherein when R2 is selected from a polyamine group, the polyamine group includes but is not limited to pentamethylenediamine, hexamethylenediamine, decanediamine or lauryldiamine, etc. From the perspective of cost, pentamethylenediamine and hexamethylenediamine are preferred. Exemplarily, the p-hydroxybenzoic acid derivative can be N,N'-bis-(3,5-di-tert-butyl-4-hydroxybenzoyl)hexamethylenediamine.

[0044] The present invention also provides a polymer resin composition, comprising a polymer resin and the above-mentioned parahydroxybenzoic acid derivative. Wherein, the polymer resin is a medical polymer resin, and the medical polymer resin includes but is not limited to polyethylene, copolymerized polyethylene, ultra-high molecular weight polyethylene, polypropylene, copolymerized polypropylene, polyvinyl chloride, polystyrene-polybutadiene-polystyrene, polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate-ethylene glycol-cyclohexanedimethanol copolymer polyester, polyethylene terephthalate-ethylene glycol-cyclohexanedimethanol ester, polyethylene terephthalate-ethylene glycol, polycarbonate resin, acrylonitrile-butadiene-styrene copolymer, nylon, nylon elastomer, polyester elastomer, styrene thermoplastic elastomer, polyolefin elastomer, butyl rubber, natural rubber or nitrile rubber.

[0045] In order to ensure proper thermal processing stability and radiation resistance, the added amount of the p-hydroxybenzoic acid derivative is preferably 0.05-0.5% of the mass of the medical polymer resin, and can be 0.05%, 0.1%, 0.2%, 0.3%, 0.4% or 0.5%, etc. That is, by weight, the polymer resin composition includes 100 parts of the medical polymer resin and 0.05-0.5 parts of the p-hydroxybenzoic acid derivative.

[0046] In some embodiments of the present invention, in order to further improve the radiation resistance and antioxidant effect of the polymer resin composition, the present invention preferably adds an antioxidant to the polymer resin composition. The amount of the antioxidant added is preferably 0.05-0.5% of the mass of the medical polymer resin, which can be 0.05%, 0.1%, 0.2%, 0.3%, 0.4% or 0.5%, etc.

[0047] In the present invention, the antioxidant includes but is not limited to phosphite antioxidants, thioether antioxidants, dihydropyridine antioxidants or amine antioxidants.

[0048] Among them, the phosphite antioxidant includes but is not limited to tris[2.4-di-tert-butylphenyl]phosphite, pentaerythritol dioctadecyl phosphite, bis[2,4-di-tert-butylphenol]pentaerythritol-diphosphite, bis(2,4-dicumylphenyl)pentaerythritol-diphosphite, 4,4'-isopropyl diphenyl C12~14 alcohol phosphite (phosphite 1500), tris[dodecyl]phosphite or 4,4'-butylene bis-(3-methyl-6-tert-butylphenyl)-tetrakis(tridecyl)diphosphite.

[0049] The thioether antioxidant includes, but is not limited to, didodecanol thiodipropionate, didecyl thiodipropionate or pentaerythritol tetrakis (3-lauryl thiopropionate).

[0050] The dihydropyridine antioxidants include, but are not limited to, 3,5-dihydropyridine dicarboxylate, 3,5-dihydropyridine dialkyl carboxylate or 2,6-dimethyl-1,4-dihydro-3,5-pyridine dicarboxylate dialkyl carboxylate.

[0051] The amine antioxidant includes but is not limited to hindered amine antioxidants or oxidized amine antioxidants, and the hindered amine antioxidant includes but is not limited to light stabilizer 292, light stabilizer 622, light stabilizer 770, light stabilizer 944, light stabilizer 2020, light stabilizer 3346, light stabilizer 3549, light stabilizer 3853, light stabilizer 4050 or light stabilizer 5050H.

[0052] The amine oxide antioxidants include but are not limited to bis(octadecyl)hydroxylamine and / or bis(octadecyl)amine oxide free radicals.

[0053] The present invention has no particular limitation on the source of the antioxidant, and any common commercially available antioxidant may be used.

[0054] Generally speaking, polymer resins containing unsaturated double bonds, such as natural rubber products, require the addition of higher levels (0.3-0.6%) of para-hydroxybenzoic acid derivatives and antioxidants. Although polyvinyl chloride materials contain only very few unsaturated double bonds, their radiation resistance is extremely poor, and they also require the addition of higher levels of antioxidants. Polyethylene, polypropylene, hydrogenated styrene thermoplastic elastomers, nylon and polyester materials generally have higher radiation resistance, and the amount of para-hydroxybenzoic acid derivatives and antioxidants added is relatively small, usually within the range of 0.05-0.2% to meet application requirements.

[0055] It should be noted that in some embodiments of the present invention, functional additives may be additionally added to the polymer resin composition according to actual needs, and the functional additives include but are not limited to nucleating agents, mold release agents, lubricants, reinforcing fillers, radiographic fillers or acid absorbents, etc. In general, the use of the functional additives is usually to improve processing efficiency. For example, nucleating agents can shorten the molding cycle and reduce problems such as warpage and deformation of injection molded parts, lubricants can reduce processing energy consumption, and acid absorbents can reduce the acid corrosion effect of materials on molds and extrusion machinery.

[0056] The present invention has no particular limitation on the selection of the above-mentioned nucleating agent, release agent, lubricant, reinforcing filler, radiographic filler or acid absorbent, and they may be selected according to the contents known to those skilled in the art.

[0057] The present invention also provides a method for preparing the polymer resin composition, comprising the following steps:

[0058] The polymer resin, the p-hydroxybenzoic acid derivative, the optional antioxidant and the optional functional auxiliary agent are mixed and then extruded to obtain a polymer resin composition.

[0059] Wherein, the extrusion is preferably carried out in a twin-screw extruder. The temperature of each zone of the twin-screw extruder can be adjusted as required without special limitation.

[0060] In some embodiments of the present invention, the p-hydroxybenzoic acid derivatives shown in Formula I are used as radiation-resistant additives and combined with different polymer resins to obtain different polymer resin compositions for testing of yellowness index and mechanical properties.

[0061] Specifically, the yellowness index determination method is as follows: the polymer resin composition is hot-pressed into a sheet with a thickness of 2 mm, irradiated with 25 kGy of electron beam, and then stored at room temperature for 3 months, placed in a colorimeter, and the yellowness index is tested in the transmission mode with a standard white plate as a reference.

[0062] The mechanical property test method is as follows: the polymer resin composition is hot pressed or injection molded into a thin sheet with a thickness of 1 mm, and the thin sheet is punched into 2-type dumbbell specimens according to the standard of GB / T 528, and electron beam irradiated with 25 kGy, and then dry-heat aged at 60°C for 2 months, and the tensile strength is tested using a universal testing machine.

[0063] The results show that the yellowness index of different polymer resin compositions after electron beam irradiation is low, indicating that they have excellent low-irradiation color change performance. In addition, the tensile strength of different polymer resin compositions after electron beam irradiation is high, indicating that they still have excellent mechanical properties after irradiation.

[0064] It can be seen that the p-hydroxybenzoic acid derivative represented by formula I provided by the present invention has the advantage of being applicable to a variety of polymer resins and has high universality, and the obtained polymer resin composition still has excellent mechanical properties after electron beam irradiation.

[0065] Based on this, the present invention also provides a medical material, which includes the polymer resin composition involved in the above technical solution.

[0066] In order to further illustrate the present invention, the following examples are provided for detailed description. The experimental materials used in the following examples of the present invention are all common commercial products.

[0067] Example 1

[0068] 10 kg of random copolymer polypropylene (melt flow rate 23 g / 10 min@230℃, content of structural unit of ethylene monomer 5 wt%), 10 g of TMP-6 nucleating agent (Shanxi Chemical Research Institute Co., Ltd.), 5 g of calcium stearate, 20 g of polypropylene wax, 10 g of 3,5-di-tert-butyl-4-hydroxybenzoic acid hexadecyl ester (light stabilizer 2908) and 5 g of antioxidant 168 were added to a high-speed mixer for uniform premixing, and then the premixed resin was added to a twin-screw for melt blending and extrusion to obtain a propylene polymer composition. The temperature of each zone of the extruder was set as follows: the feeding section temperature was 125℃, the temperature of other sections was 240℃, the head and die temperature were 220℃, and the main screw speed was 600 r / min.

[0069] Example 2

[0070] 10 kg of linear low-density polyethylene (grade DFDA 7042, melt flow rate 1 g / 10 min@190°C), 5 g of calcium stearate, 20 g of polyethylene wax, 10 g of 3,5-di-tert-butyl-4-hydroxybenzoic acid hexadecyl ester and 5 g of antioxidant 168 were added to a high-speed mixer for uniform premixing, and then the premixed resin was added to a twin-screw for melt blending and extrusion to obtain a polyethylene polymer composition. The temperature of each zone of the extruder was set as follows: the feeding section temperature was 100°C, the other section temperatures were 230°C, the head and die temperatures were 210°C, and the main screw speed was 600 r / min.

[0071] Example 3

[0072] 5 kg of hydrogenated polystyrene-polybutadiene-polystyrene (brand name Kraton G 1651) and 5 kg of polypropylene, 5 g of calcium stearate, 20 g of polypropylene wax, 10 g of 3,5-di-tert-butyl-4-hydroxybenzoic acid hexadecyl ester and 5 g of antioxidant 168 were added to a high-speed mixer for uniform premixing, and then the premixed resin was added to a twin-screw for melt blending and extrusion to obtain a polyethylene polymer composition. The temperature of each zone of the extruder was set as follows: the temperature of the feeding section was 100°C, the temperature of other sections was 230°C, the temperature of the head and the die was 210°C, and the speed of the main screw was 600 r / min.

[0073] Example 4

[0074] 100 kg of polyvinyl chloride resin powder (Formosa Plastics S70 resin powder), 60 kg of plasticizer DINCH, 8 kg of epoxidized soybean oil, 200 g of calcium stearate, 200 g of zinc stearate, 200 g of oxidized polyethylene wax, 250 g of 3,5-di-tert-butyl-4-hydroxybenzoic acid hexadecyl ester and 200 g of antioxidant 618 were added to a high-speed mixer and premixed evenly, mixed to 130°C, and then cooled to below 60°C under stirring, and then the premixed resin was added to a conical twin-screw for melt extrusion and granulation to obtain a polyvinyl chloride resin composition. The temperature of each zone of the extruder was set as follows: the feeding section temperature was 100°C, the other section temperatures were 160°C, the head and die temperatures were 160°C, and the main screw speed was 300 r / min.

[0075] Example 5

[0076] 10 kg of acrylonitrile-butadiene-styrene copolymer (grade PA-704 LRP), 20 g of hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate and 5 g of antioxidant 168 were added to a high-speed mixer and premixed evenly. The premixed resin was then added to a twin-screw extruder for melt blending and extrusion to obtain a polyethylene polymer composition. The temperature of each zone of the extruder was set as follows: the temperature of the feeding section was 200°C, the temperature of other sections was 230°C, the temperature of the die head and the die was 210°C, and the speed of the main screw was 600 r / min.

[0077] Example 6

[0078] Tetrakis (3,5-di-tert-butyl-4-hydroxybenzoic acid) pentaerythritol ester was synthesized according to the U.S. patent with publication number US4619957. 10 kg of polyethylene terephthalate-ethylene glycol-cyclohexanedimethanol ester (intrinsic viscosity 0.80 dL / g), 30 g of Incromax 100 mold release agent, and 10 g of tetrakis (3,5-di-tert-butyl-4-hydroxybenzoic acid) pentaerythritol ester were added to a high-speed mixer for premixing, and then the premixed resin was added to a twin-screw for melt blending and extrusion to obtain a polyethylene polymer composition. The temperature of each zone of the extruder was set as follows: the feeding section temperature was 200°C, the temperature of other sections was 260°C, the head and die temperature were 250°C, and the main screw speed was 600 r / min.

[0079] Example 7

[0080] Tetrakis (3,5-di-tert-butyl-4-hydroxybenzoic acid) pentaerythritol ester was synthesized according to the U.S. patent with publication number US4619957. 10 kg of polyethylene terephthalate (0.75 dL / g), 10 g of nucleating agent Licomont NaV 101, 30 g of Incromax 300 release agent, and 10 g of tetrakis (3,5-di-tert-butyl-4-hydroxybenzoic acid) pentaerythritol ester were added to a high-speed mixer for premixing, and then the premixed resin was added to a twin-screw for melt blending and extrusion to obtain a polyethylene polymer composition. The temperature of each zone of the extruder was set as follows: the temperature of the feeding section was 260°C, the temperature of other sections was 275°C, the temperature of the die head and the die was 265°C, and the main screw speed was 600 r / min.

[0081] Example 8

[0082] Tetrakis (3,5-di-tert-butyl-4-hydroxybenzoic acid) pentaerythritol ester was synthesized according to the U.S. patent with publication number US4619957. 10 kg of polycarbonate resin, 30 g of Incromax 300 mold release agent, and 10 g of tetrakis (3,5-di-tert-butyl-4-hydroxybenzoic acid) pentaerythritol ester were added to a high-speed mixer for premixing, and then the premixed resin was added to a twin-screw for melt blending and extrusion to obtain a polyethylene polymer composition. The temperature of each zone of the extruder was set as follows: the temperature of the feeding section was 260°C, the temperature of other sections was 300°C, the temperature of the die head and the die was 280°C, and the main screw speed was 600 r / min.

[0083] Example 9

[0084] Tetrakis (3,5-di-tert-butyl-4-hydroxybenzoic acid) pentaerythritol ester was synthesized according to the U.S. patent publication number US4619957. 10 kg of nylon 12 resin (brand name VESTAMID ML21) and 20 g of tetrakis (3,5-di-tert-butyl-4-hydroxybenzoic acid) pentaerythritol ester were added to a high-speed mixer for premixing, and then the premixed resin was added to a twin-screw for melt blending and extrusion to obtain a polyethylene polymer composition. The temperature of each zone of the extruder was set as follows: the temperature of the feeding section was 200°C, the temperature of other sections was 240°C, the temperature of the die head and the die was 220°C, and the main screw speed was 600 r / min.

[0085] Comparative Example 1

[0086] Compared with Example 1, the mass of 3,5-di-tert-butyl-4-hydroxybenzoic acid hexadecyl ester was replaced with 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate n-octadecyl ester (antioxidant 1076), and the other conditions were the same as those in Example 1.

[0087] Comparative Example 2

[0088] Compared with Example 2, the mass of 3,5-di-tert-butyl-4-hydroxybenzoic acid hexadecyl ester was replaced with antioxidant 1076, and the other conditions were the same as those in Example 2.

[0089] Comparative Example 3

[0090] Compared with Example 3, the mass of 3,5-di-tert-butyl-4-hydroxybenzoic acid hexadecyl ester was replaced with antioxidant 1010, and the other conditions were the same as those in Example 3.

[0091] Comparative Example 4

[0092] Compared with Example 4, the mass of 3,5-di-tert-butyl-4-hydroxybenzoic acid hexadecyl ester was replaced with antioxidant 245, and the other conditions were the same as those in Example 4.

[0093] Comparative Example 5

[0094] Compared with Example 5, the mass of 3,5-di-tert-butyl-4-hydroxybenzoic acid hexadecyl ester was replaced with antioxidant 1010, and the other conditions were the same as those in Example 5.

[0095] Comparative Example 6

[0096] Compared with Example 6, the mass of pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxybenzoate) was replaced with antioxidant 1010, and the other conditions were the same as those in Example 6.

[0097] Comparative Example 7

[0098] Compared with Example 7, the mass of pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxybenzoate) was replaced with antioxidant 1010, and the other conditions were the same as those in Example 7.

[0099] Comparative Example 8

[0100] Compared with Example 8, the mass of pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxybenzoate) was replaced with antioxidant 1010, and the other conditions were the same as those in Example 8.

[0101] Comparative Example 9

[0102] Compared with Example 9, the mass of pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxybenzoate) was replaced with antioxidant 1098, and the other conditions were the same as those of Example 9.

[0103] Comparative Example 10

[0104] Compared with Example 1, the mass of 3,5-di-tert-butyl-4-hydroxybenzoic acid hexadecyl ester was replaced with hindered amine 944, and the other conditions were the same as those in Example 1.

[0105] Comparative Example 11

[0106] Compared with Example 4, the mass of 3,5-di-tert-butyl-4-hydroxybenzoic acid hexadecyl ester was replaced with hindered amine 944, and the other conditions were the same as those of Example 4.

[0107] Performance Testing

[0108] The yellowness index and mechanical properties of the polymer resin compositions obtained in the above examples and comparative examples were tested in the following manner:

[0109] Yellowness index: The polymer resin compositions of each group were hot-pressed into sheets with a thickness of 2 mm, irradiated with 25 kGy of electron beam, and then stored at room temperature for 3 months. The sheets were placed in a colorimeter and the yellowness index was tested in the transmission mode with a standard white plate as a reference.

[0110] Mechanical properties: The polymer resin compositions of each group were hot pressed or injection molded into thin sheets with a thickness of 1 mm. Referring to the standard of GB / T 528, the thin sheets were punched into type 2 dumbbell specimens, irradiated with 25 kGy of electron beam or without electron beam irradiation, and then dry-heat aged at 60°C for 2 months. The tensile strength was tested using a universal testing machine.

[0111] The test results are shown in Table 1 below:

[0112] Table 1

[0113]

[0114] It can be seen from Comparative Examples 10 and 11 in Table 1 that when hindered amines are used as anti-radiation additives, when applied to polypropylene, the yellowness index of the polymer resin composition after radiation aging is very small, but when applied to polyvinyl chloride materials, the yellowness index of the polymer resin composition after radiation aging increases significantly, indicating that hindered amines have application limitations as anti-radiation additives.

[0115] From the comparison between Examples 1 to 10 and Comparative Examples 1 to 9, it can be seen that the p-hydroxybenzoic acid derivatives provided by the present invention have consistent low radiation discoloration performance in a variety of medical polymer resins. Compared with the common antioxidant 1010, antioxidant 245, and antioxidant 1098, the present invention also has the advantage that the color of the polymer resin is lighter after irradiation.

[0116] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A polymer resin composition, characterized in that The composition comprises 100 parts of polymer resin and 0.05-0.5 parts of p-hydroxybenzoic acid derivative by weight; The structural formula of the p-hydroxybenzoic acid derivative is shown in Formula I: Formula I; Wherein, R1 is selected from H atom, methyl or tert-butyl; R2 is selected from an alkoxy group having 8 or more carbon atoms, a polyol group or a polyamine group.

2. The polymer resin composition according to claim 1, characterized in that The alkoxy group having 8 or more carbon atoms includes, but is not limited to, octyloxy, decyloxy, lauryloxy, hexadecyloxy, octadecyloxy, or behenyloxy; The polyol group includes but is not limited to ethylene glycol, propylene glycol, butylene glycol, hexanediol, decanediol, glycerol, ethanetrimethylol, propanetrimethylol, pentaerythritol or dipentaerythritol hexanol; The polyamine group includes, but is not limited to, a pentanediamine group, a hexanediamine group, a decanediamine group, or a lauryldiamine group.

3. The polymer resin composition according to claim 1 or 2, characterized in that: The p-hydroxybenzoic acid derivative is selected from any one or more of 3,5-di-tert-butyl-4-hydroxybenzoic acid octadecyl ester, 3,5-di-tert-butyl-4-hydroxybenzoic acid hexadecyl ester, di(3,5-di-tert-butyl-4-hydroxybenzoic acid)-triethylene glycol ester, tetrakis(3,5-di-tert-butyl-4-hydroxybenzoic acid) pentaerythritol ester, N,N'-bis-(3,5-di-tert-butyl-4-hydroxybenzoyl) hexanediamine, N,N'-bis-(3,5-di-tert-butyl-4-hydroxybenzoyl) pentamethylenediamine and N,N'-bis-(3,5-di-tert-butyl-4-hydroxybenzoyl) decanediamine.

4. The polymer resin composition according to any one of claims 1 to 3, characterized in that The polymer resin is a medical polymer resin; The medical polymer resin includes but is not limited to polyethylene, copolymer polyethylene, ultra-high molecular weight polyethylene, polypropylene, copolymer polypropylene, polyvinyl chloride, polystyrene-polybutadiene-polystyrene, polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate-ethylene glycol-cyclohexanedimethanol copolymer polyester, polyethylene terephthalate-ethylene glycol-cyclohexanedimethanol ester, polyethylene terephthalate-ethylene glycol, polycarbonate resin, acrylonitrile-butadiene-styrene copolymer, nylon, nylon elastomer, polyester elastomer, styrene thermoplastic elastomer, polyolefin elastomer, butyl rubber, natural rubber or nitrile rubber.

5. The polymer resin composition according to any one of claims 1 to 4, characterized in that The polymer resin composition also includes an antioxidant; The antioxidant includes, but is not limited to, phosphite antioxidants, thioether antioxidants, dihydropyridine antioxidants or amine antioxidants.

6. The polymer resin composition according to claim 5, characterized in that The phosphite antioxidant includes but is not limited to tris[2,4-di-tert-butylphenyl]phosphite, dioctadecyl pentaerythritol diphosphite, bis[2,4-di-tert-butylphenol]pentaerythritol-diphosphite, bis(2,4-dicumylphenyl)pentaerythritol-diphosphite, 4,4'-isopropyl diphenyl C12~14 alcohol phosphite (phosphite 1500), tris[dodecyl]phosphite or 4,4'-butylenebis-(3-methyl-6-tert-butylphenyl)-tetrakis(tridecyl)diphosphite; The thioether antioxidant includes but is not limited to didodecyl thiodipropionate, didecyl thiodipropionate or pentaerythritol tetrakis (3-lauryl thiopropionate); The dihydropyridine antioxidants include but are not limited to 3,5-dihydropyridine dicarboxylate, 3,5-dihydropyridine dialkyl carboxylate or 2,6-dimethyl-1,4-dihydro-3,5-pyridine dicarboxylate; The amine antioxidant includes but is not limited to hindered amine antioxidants or oxidized amine antioxidants, and the hindered amine antioxidants include but are not limited to light stabilizer 292, light stabilizer 622, light stabilizer 770, light stabilizer 944, light stabilizer 2020, light stabilizer 3346, light stabilizer 3549, light stabilizer 3853, light stabilizer 4050 or light stabilizer 5050H; The amine oxide antioxidants include but are not limited to bis(octadecyl)hydroxylamine and / or bis(octadecyl)amine oxide free radicals.

7. The polymer resin composition according to claim 5 or 6, characterized in that: The polymer resin composition comprises, by weight, 100 parts of polymer resin, 0.05-0.5 parts of p-hydroxybenzoic acid derivatives, and 0.05-0.5 parts of antioxidants.

8. The polymer resin composition according to any one of claims 1 to 7, characterized in that The polymer resin composition also includes a functional auxiliary agent; The functional auxiliary agent includes, but is not limited to, a nucleating agent, a mold release agent, a lubricant, a reinforcing filler, a radiographic filler or an acid absorbent.

9. A method for preparing a polymer resin composition according to any one of claims 1 to 8, characterized in that: The following steps are involved: The polymer resin, the p-hydroxybenzoic acid derivative, the optional antioxidant and the optional functional auxiliary agent are mixed and then extruded to obtain a polymer resin composition.

10. A medical material, characterized in that: The invention comprises the polymer resin composition according to any one of claims 1 to 8 or the polymer resin composition prepared by the preparation method according to claim 9.

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