PVC (polyvinyl chloride) material yellowing-resistant modifier, irradiation yellowing-resistant PVC material and preparation method of PVC material

Abstract

The invention provides a PVC (polyvinyl chloride) material yellowing-resistant modifier, a PVC material resistant to irradiation yellowing and a preparation method of the PVC material, and relates to the technical field of high polymer materials. The PVC material anti-yellowing modifier is formed by compounding a chlorine free radical capturing agent, a molecular chain repairing agent and an HCl absorbent. According to the invention, three free radical capturing agents are adopted for synergistic effect, PVC molecular structure is stabilized from multiple aspects of capturing chlorine free radicals, repairing PVC molecular main chains, absorbing generated HCl and the like, and material yellowing factors are eliminated.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a yellowing-resistant modifier for PVC materials with a small yellow index change after electron beam irradiation sterilization, a PVC material and a preparation method thereof. Background Art

[0002] PVC (polyvinyl chloride) material has excellent transparency and chemical resistance, and its hardness can vary with the amount of added plasticizer. It is one of the most consumed plastic materials in the field of disposable medical products.

[0003] Medical material sterilization methods usually include high-temperature steam sterilization, ethylene oxide sterilization, and electron beam irradiation sterilization. The commonly used sterilization method for PVC medical materials is ethylene oxide sterilization. On October 27, 2017, the World Health Organization's International Agency for Research on Cancer included ethylene oxide in the list of Class 1 carcinogens. The use of ethylene oxide sterilization has the risk of polluting the environment. The ethylene oxide remaining on medical devices is also likely to affect human health. In addition, ethylene oxide is flammable and explosive, and safety accidents are prone to occur. Electron beam irradiation sterilization has the characteristics of short time and no residue. It has been increasingly widely used in the field of medical device disinfection abroad and has become the development direction of sterilization of disposable medical supplies.

[0004] The main reason why PVC medical products are not widely used in electron beam irradiation sterilization is that the material has poor radiation resistance. When irradiated with electron beams, the color of the material changes greatly, and the material even turns dark brown. Therefore, it is very urgent to solve the problem of severe yellowing of PVC medical materials after electron beam irradiation sterilization. Summary of the invention

[0005] In view of the deficiencies of the prior art, the present invention provides a yellowing-resistant modifier for PVC materials, a radiation-resistant yellowing PVC material and a preparation method thereof. The PVC medical products produced therefrom can be suitable for electron beam irradiation sterilization.

[0006] One of the purposes of the present invention is to provide a yellowing resistance modifier for PVC materials.

[0007] The second object of the present invention is to provide a PVC material resistant to yellowing due to radiation, comprising the PVC material yellowing resistance modifier.

[0008] The third object of the present invention is to provide a method for preparing the radiation yellowing resistant PVC material.

[0009] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0010] In a first aspect, the present invention provides a yellowing resistance modifier for PVC materials, which is composed of a chlorine radical scavenger, a molecular chain repair agent and an HCl absorber, wherein the mass ratio of the chlorine radical scavenger, the molecular chain repair agent and the HCl absorber is preferably (4.5-5.0):(0.8-1.0):(2.5-2.8).

[0011] In a second aspect, the present invention provides a PVC material resistant to yellowing due to radiation, comprising the following components in parts by mass: 100 parts of PVC resin, 1.2 to 1.5 parts of stabilizer, 45 to 55 parts of primary plasticizer, 3 to 5 parts of auxiliary plasticizer, 0.4 to 0.6 parts of lubricant, 0.8 to 1.2 parts of antioxidant, and 1.2 to 1.5 parts of the above-mentioned yellowing resistance modifier.

[0012] The following is a detailed description of each component:

[0013] There is no particular limitation on the source of the PVC resin, which can be commercially available or prepared by itself according to methods known in the art.

[0014] Preferably, the PVC resin is prepared by suspension polymerization of vinyl chloride monomer obtained by petroleum-ethylene process. Preferably, the average polymerization degree of the PVC resin is 1000-2500, preferably 1000, but not limited thereto.

[0015] The added amount of PVC resin is 100 parts.

[0016] The stabilizer may be any stabilizer known in the art.

[0017] Preferably, the stabilizer is an environmentally friendly and tasteless calcium zinc stabilizer, such as AIMSTA-6802 from Shenzhen Zhihai Industrial Co., Ltd., but is not limited thereto.

[0018] The amount of the stabilizer added is 1.2 to 1.5 parts, for example, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, but not limited thereto.

[0019] The primary plasticizer may include but is not limited to diisooctyl cyclohexane-1,2-dicarboxylate (DEHCH), diisononyl cyclohexane-1,2-dicarboxylate (DINCH), dioctyl sebacate (DOS), etc., preferably diisononyl cyclohexane-1,2-dicarboxylate (DINCH) plasticizer.

[0020] The amount of the main plasticizer added is 45 to 55 parts, for example, 46 parts, 47 parts, 48 ​​parts, 49 parts, 50 parts, 51 parts, 52 parts, 53 parts, 54 parts, but not limited thereto.

[0021] The auxiliary plasticizer is epoxidized soybean oil (ESBO) having an auxiliary stabilizing effect. Preferably, the epoxidized soybean oil (ESBO) has an epoxide value of ≥6.2%, such as HM-01AD produced by Nantong Haierma Technology Co., Ltd., but not limited thereto.

[0022] The amount of the auxiliary plasticizer added is 3 to 5 parts, for example, 3 parts, 4 parts, or 5 parts, but is not limited thereto.

[0023] The lubricant may be a lubricating resin known in the art, including but not limited to low-density oxidized polyethylene wax lubricants, such as AC-629A from Honeywell, but not limited thereto.

[0024] The amount of lubricant added is 0.4 to 0.6 parts, for example, 0.4 parts, 0.5 parts, or 0.6 parts, but is not limited thereto.

[0025] The antioxidant may be any antioxidant known in the art, including but not limited to non-polluting hindered phenol antioxidants and hindered amine antioxidants.

[0026] Preferably, the antioxidant is triethylene glycol bis[β-(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate] (antioxidant 245), but is not limited thereto.

[0027] The amount of the antioxidant added is 0.8 to 1.2 parts, for example, 0.8 parts, 0.9 parts, 1 part, 1.1 parts, 1.2 parts, but not limited thereto.

[0028] The anti-yellowing modifier is composited by a chlorine free radical scavenger, a molecular chain repair agent and an HCl absorbent, wherein the mass ratio of the chlorine free radical scavenger, the molecular chain repair agent and the HCl absorbent is (4.5-5.0):(0.8-1.0):(2.5-2.8).

[0029] The chlorine free radical scavenger may include, but is not limited to, bis(2,4-di-tert-butylphenyl)pentaerythritol bisdiphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphate, bis(2,4-dicumylphenyl)pentaerythritol-diphosphite, tris(1,2,2,6,6-pentamethylpiperidinyl)phosphite, etc., preferably tris(1,2,2,6,6-pentamethylpiperidinyl)phosphite.

[0030] The molecular chain repair agent may include but is not limited to N,N-diethylhydroxylamine (DEHA) or N-isopropylhydroxylamine (IPHA), etc., preferably N-isopropylhydroxylamine (IPHA).

[0031] The HCl absorbent may be ternary hydrotalcite.

[0032] The amount of the anti-yellowing modifier added is 1.2 to 1.5 parts, for example, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, but not limited thereto.

[0033] In a third aspect, the present invention provides a method for preparing the above-mentioned radiation-resistant yellowing PVC material, comprising the following steps: mixing PVC resin, stabilizer, primary plasticizer, auxiliary plasticizer, lubricant, antioxidant, and yellowing resistance modifier to obtain the radiation-resistant yellowing PVC material.

[0034] Specifically, the preparation method comprises:

[0035] (1) Raw material mixing: Add PVC resin, stabilizer, lubricant, primary plasticizer and auxiliary plasticizer into a high-speed mixer, stir and heat, then add antioxidant and anti-yellowing modifier, continue stirring and heating, put the materials into a low-speed mixer, stir, and discharge the materials after cooling;

[0036] (2) Granulation: The mixed materials are granulated by a twin-screw extruder to obtain a special PVC material that is resistant to yellowing due to radiation.

[0037] In some embodiments, in step (1), a high-speed mixer is added and stirred at a speed of 3000-4000 rpm to raise the temperature to 100-110° C.; and stirring is continued at a speed of 3000-4000 rpm to raise the temperature to 125-135° C.

[0038] In some embodiments, in step (1), the material is placed in a low-speed mixer and stirred at a speed of 300-400 rpm, and the material is discharged after cooling to 40°C.

[0039] In some embodiments, in step (2), the granulation temperature is 120°C to 150°C, preferably 140°C to 145°C.

[0040] Beneficial effects:

[0041] The inventors of the present invention have found that after PVC material is irradiated by electron beam, unstable allyl chlorine atoms in the PVC molecular chain are easily removed and a chain reaction occurs, forming a conjugated double bond structure in the molecular chain, which causes the material to turn yellow and the main chain of the PVC molecule is also easily broken. In order to solve this problem, the present invention creatively uses three free radical scavengers to work synergistically, stabilize the PVC molecular structure from multiple aspects such as capturing chlorine free radicals, repairing the main chain of the PVC molecule, and absorbing the generated HCl, thereby eliminating the yellowing factor of the material.

[0042] The test results show that the yellow index change of the PVC material prepared by the anti-yellowing modifier composed of three free radical scavengers of the present invention before and after irradiation is about 5-6, which is at least twice as much as the yellow index change of the common PVC material without adding the anti-yellowing modifier and the PVC material with only adding one of the free radical scavengers before and after irradiation; the thermal stability of the PVC material prepared by the anti-yellowing modifier composed of three free radical scavengers of the present invention can reach more than 60 minutes, while the thermal stability of the common PVC material is only 50 minutes; in addition, the mechanical properties of the PVC material after adding the anti-yellowing modifier are not affected.

[0043] The present invention has been described in detail above, but the above embodiments are only illustrative in nature and are not intended to limit the present invention. In addition, this article is not limited by any theory described in the above prior art or invention content or the following examples. DETAILED DESCRIPTION

[0044] The present invention is further described below in conjunction with examples. It should be noted that the following examples are provided for illustrative purposes only and do not constitute a limitation on the scope of protection claimed for the present invention.

[0045] Unless otherwise specified, the raw materials, reagents, methods, etc. used in the examples are conventional raw materials, reagents, methods in the art.

[0046] The raw materials involved in the embodiments and comparative examples are as follows:

[0047] PVC S-1000 resin is produced by Qilu Petrochemical Company.

[0048] The calcium zinc stabilizer is AIMSTA-6802 from Shenzhen Zhihai Industrial Co., Ltd.

[0049] The main plasticizer is diisononyl cyclohexane-1,2-dicarboxylate (DINCH) from BASF.

[0050] The auxiliary plasticizer is HM-01AD produced by Nantong Haierma Technology Co., Ltd.

[0051] The lubricant is AC-629A from Honeywell.

[0052] The antioxidant was antioxidant 245 from Tianjin Lianlong New Materials Co., Ltd.

[0053] Tris(1,2,2,6,6-pentamethylpiperidinyl)phosphite was produced by Shijiazhuang Hongsen Chemical Company.

[0054] N-isopropylhydroxylamine is produced by Guangzhou Yuanda New Materials Co., Ltd.

[0055] Ternary hydrotalcite is produced by Chenghe Technology Co., Ltd.

[0056] Examples and Comparative Examples

[0057] The PVC material formulations (parts by mass) of Examples 1 to 10 and Comparative Examples 1 to 4 are shown in Tables 1 to 3.

[0058] Table 1

[0059] Components Example 1 Example 2 Example 3 Example 4 Example 5 PVC S-1000 100 100 100 100 100 Calcium zinc stabilizer 1.5 1.5 1.2 1.3 1.4 Primary plasticizer 50 55 45 50 50 Auxiliary plasticizer 5 3 4 4 4 Lubricants 0.5 0.5 0.5 0.6 0.4 Antioxidants 1.2 1.0 1.1 1.2 0.8 Anti-yellowing modifier 1.5 1.2 1.4 1.3 1.3

[0060] In Examples 1 to 5, the composite formula of the anti-yellowing modifier is: tris(1,2,2,6,6-pentamethylpiperidinyl)phosphite, N-isopropylhydroxylamine and ternary hydrotalcite, and the mass ratio of tris(1,2,2,6,6-pentamethylpiperidinyl)phosphite, N-isopropylhydroxylamine and ternary hydrotalcite is 5.0:0.8:2.5.

[0061] Table 2

[0062]

[0063]

[0064] In Examples 6 to 10, the composite formula of the anti-yellowing modifier is: tris(1,2,2,6,6-pentamethylpiperidinyl)phosphite, N-isopropylhydroxylamine and ternary hydrotalcite, and the mass ratio of tris(1,2,2,6,6-pentamethylpiperidinyl)phosphite, N-isopropylhydroxylamine and ternary hydrotalcite is 4.5:1.0:2.8.

[0065] Table 3

[0066]

[0067] Example and Comparative Example Sample Preparation and Performance Testing Methods:

[0068] (1) Raw material mixing: PVC resin, stabilizer, lubricant, primary plasticizer and auxiliary plasticizer are added to a high-speed mixer for mixing. When the temperature is raised to 100° C. at a speed of 3000 rpm, antioxidant and anti-yellowing modifier are added. The temperature is raised to 125° C. at a speed of 3000 rpm. The materials are placed in a low-speed mixer and stirred at a speed of 300 rpm. The materials are discharged when the temperature is cooled to 40° C.

[0069] (2) Special material granulation process: The mixed materials are granulated by twin screw extruder at a granulation temperature of 140℃~145℃.

[0070] (3) The pellets were plasticized on a double-roll mill at a temperature of 165°C for 3 min, and then molded into 0.5 mm thick specimens using a press, and then made into dumbbell-shaped specimens for performance testing.

[0071] Test standards: A. Tensile strength and elongation at break are tested in accordance with GB / T 1040.2-2022 "Determination of tensile properties of plastics Part 2 Test conditions for molded and extruded plastics". B. Yellow index is tested in accordance with HB / T 3802-2006 "Plastic yellow index test method". C. The electron beam irradiation dose of the sample is 25kGy. D. Thermal stability time is tested in accordance with GB / T2917.1-2002 "Determination of hydrogen chloride and any other acidic products released by blends and products based on vinyl chloride homopolymers and copolymers at high temperatures - Congo red method".

[0072] The test performance results are shown in Tables 4 to 6:

[0073] Table 4

[0074]

[0075] Table 5

[0076]

[0077] Table 6

[0078]

[0079]

[0080] Comparative Examples Compared with the corresponding embodiments, no free radical scavenger was added in Comparative Example 1, and free radical scavengers were used alone in Comparative Examples 2, 3 and 4. From the yellow index of the samples before and after irradiation, the changes of the comparative examples were large.

[0081] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents, without departing from the spirit and essence of the claims of the present invention; and these modifications or replacements are still within the scope defined by the claims of the present invention.

Claims

1. A yellowing resistance modifier for PVC material, characterized in that: The anti-yellowing modifier comprises a chlorine free radical scavenger, a molecular chain repair agent and an HCl absorbent.

2. The anti-yellowing modifier for PVC material according to claim 1, characterized in that: The chlorine free radical scavenger is one or more selected from bis(2,4-di-tert-butylphenyl)pentaerythritol bisdiphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphate, bis(2,4-dicumylphenyl)pentaerythritol-diphosphite and tris(1,2,2,6,6-pentamethylpiperidinyl)phosphite, preferably tris(1,2,2,6,6-pentamethylpiperidinyl)phosphite; The molecular chain repair agent is one or two selected from N,N-diethylhydroxylamine (DEHA) and N-isopropylhydroxylamine (IPHA), preferably N-isopropylhydroxylamine (IPHA); The HCl absorbent is ternary hydrotalcite.

3. The anti-yellowing modifier for PVC material according to claim 1, characterized in that: The mass ratio of the chlorine free radical scavenger, the molecular chain repair agent and the HCl absorbent is (4.5-5.0):(0.8-1.0):(2.5-2.8).

4. A PVC material resistant to yellowing due to radiation, characterized in that: The invention comprises the following components by mass: 100 parts of PVC resin, 1.2-1.5 parts of stabilizer, 45-55 parts of primary plasticizer, 3-5 parts of auxiliary plasticizer, 0.4-0.6 parts of lubricant, 0.8-1.2 parts of antioxidant, and 1.2-1.5 parts of the anti-yellowing modifier of PVC material according to any one of claims 1 to 3.

5. The radiation yellowing resistant PVC material according to claim 4, characterized in that: The PVC resin is prepared by using a petroleum-ethylene process to obtain vinyl chloride monomer and then polymerizing it through a suspension process; Preferably, the average degree of polymerization of the PVC resin is 1000 to 2500; Preferably, the stabilizer is a calcium zinc stabilizer; Preferably, the primary plasticizer is one or more selected from diisooctyl cyclohexane-1,2-dicarboxylate, diisononyl cyclohexane-1,2-dicarboxylate and dioctyl sebacate, preferably diisononyl cyclohexane-1,2-dicarboxylate.

6. The radiation yellowing resistant PVC material according to claim 4, characterized in that: The auxiliary plasticizer is epoxidized soybean oil; Preferably, the epoxidation value of the epoxidized soybean oil is ≥6.2%.

7. The radiation yellowing resistant PVC material according to claim 4, characterized in that: The lubricant is low-density oxidized polyethylene wax.

8. The radiation yellowing resistant PVC material according to claim 4, characterized in that: The antioxidant is a hindered phenol antioxidant, preferably triethylene glycol bis[β-(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate].

9. A method for preparing the radiation yellowing resistant PVC material according to any one of claims 4 to 8, characterized in that: The following steps are involved: (1) Raw material mixing: PVC resin, stabilizer, lubricant, primary plasticizer and auxiliary plasticizer are added to a high-speed mixer, stirred and heated, and then antioxidant and the PVC material anti-yellowing modifier are added, and the stirring and heating are continued. The materials are placed in a low-speed mixer for stirring, and the materials are discharged after being cooled; (2) Granulation: The mixed materials are granulated by a twin-screw extruder to obtain a special PVC material that is resistant to yellowing due to radiation.

10. The preparation method according to claim 9, characterized in that: In step (1), add a high-speed mixer and stir at a speed of 3000-4000 rpm to raise the temperature to 100-110° C.; continue stirring at a speed of 3000-4000 rpm to raise the temperature to 125-135° C.; In step (1), the material is placed in a low-speed mixer and stirred at a speed of 300-400 rpm, and the material is discharged after cooling to 40° C.; In step (2), the granulation temperature is 120°C to 150°C, preferably 140°C to 145°C.

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