PVC (polyvinyl chloride) composition as well as preparation method and application thereof

Abstract

The invention discloses a PVC (polyvinyl chloride) composition as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials, a terpolymer, a carbon free radical capturing agent and nano halloysite are introduced into a matrix system of PVC resin and a plasticizer as functional components, and the functional components are combined on the basis of the synergistic effect of the terpolymer, the carbon free radical capturing agent and the nano halloysite. The tensile strength and tear strength of the product can be effectively improved, and the product has excellent fatigue resistance and humidity and heat resistance, is long in service life and can meet the performance index requirements of the outer packaging product industry.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly relates to a PVC composition, a preparation method thereof and an application thereof. Background Art

[0002] PVC (polyvinyl chloride) materials with a high plasticizer content have an elastic feel similar to rubber and are frequently used in some outer packaging products, such as skins, curtains, coatings, etc. In such materials, the mass ratio of the PVC matrix to the plasticizer basically reaches about 1:1.

[0003] However, due to the introduction of the plasticizer, the intrinsic tensile strength and tear strength of this material are relatively low. Especially for the outer packaging products with a relatively thin size, the mechanical property disadvantages are further amplified. In addition, such thin products are more susceptible to external forces and the external humid and hot environment, and the fatigue resistance and humid and heat resistance of the products are poor, and the application indexes basically cannot meet the industry standards of the new generation of outer packaging products. Summary of the Invention

[0004] Based on the defects existing in the prior art, the purpose of the present invention is to provide a PVC composition. In the matrix system of PVC resin and plasticizer, a terpolymer, a carbon free radical scavenger and nano halloysite are introduced as functional components. Based on the synergistic effect of the three, not only can the tensile strength and tear strength of the product be effectively improved, but also the product has excellent fatigue resistance and humid and heat resistance, and the service life of the product is long, meeting the performance index requirements of the outer packaging product industry.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A PVC composition, comprising the following components in parts by weight:

[0007] 45 - 55 parts of PVC resin, 45 - 55 parts of plasticizer, 7.5 - 19 parts of terpolymer, 2 - 5 parts of nano halloysite, 0.5 - 1.25 parts of carbon free radical scavenger and 5 - 10 parts of stabilizer;

[0008] The terpolymer includes at least one of ethylene-butyl acrylate-carbon monoxide random copolymer (CAS 61843-70-7) and ethylene-vinyl acetate-carbon monoxide random copolymer (CAS 26337-35-9);

[0009] The carbon free radical scavenger includes a hydroxybenzoate type carbon free radical scavenger.

[0010] Introducing plasticizers into PVC resin can endow the product with an elastic feel similar to that of rubber, enabling this composite material to be applied to some outer packaging products that require both feel, such as skins, curtains, coatings, etc. However, the introduction of plasticizers also leads to a significant attenuation in the mechanical properties of the product, such as tensile strength and tear strength. Especially when the outer packaging product needs to be cut and injection-molded into thin dimensions on the order of millimeters, the disadvantages of this mechanical property will be further amplified. At the same time, due to the characteristics of the PVC molecular weight, when subjected to external forces, the material is prone to obvious fatigue phenomena. In severe cases, based on the batch fracture of PVC molecular chains, material cracks or even fractures may occur. In addition, after being made into thin products, this material is more susceptible to the influence of humid and hot environments, with an obvious degradation trend. The service performance of the product will rapidly decay in a short time, and the service life is short, and it simply cannot meet the industry standards of existing outer packaging products.

[0011] Therefore, in the technical solution of the present invention, after introducing plasticizers and compounding with PVC resin, the product further introduces a specific terpolymer, nano-halloysite, and benzoate-type carbon radical scavenger compounded as functional components, which can significantly improve the tensile strength and tear strength of the product. Moreover, the terpolymer constructed with ethylene and carbon monoxide as monomers not only has good compatibility with PVC resin, but also can achieve the isolation effect between PVC molecules based on the vinyl non-polar groups, making the PVC molecular weight more relaxed and inhibiting the fatigue effect of external forces on the product. On the other hand, the nano-halloysite (also known as halloysite nanotubes HNTs) in the product has rich surface Si-O bonds, so it also has a strong interfacial bonding strength with polar PVC resin. At the same time, due to its special tubular nano-structure, it is evenly distributed in a three-dimensional staggered state in the product and can achieve an effective stress transfer effect, jointly with the terpolymer to improve the fatigue resistance of the material. In addition, this material can also absorb the hydrogen chloride corrosion gas generated by PVC resin under the influence of external factors, which can not only further improve the anti-stress stability of the product, but also jointly with the special hydroxybenzoate-type carbon radical scavenger inhibit the degradation reaction of the product under external forces or humid and hot factors, delay the fracture of PVC molecular chains, and significantly improve the fatigue resistance and humid and heat resistance of the product synchronously.

[0012] If these three components are not selected for combination, or other components with similar functions are used for replacement, the product cannot balance excellent comprehensive performance, especially it is difficult to meet the standards simultaneously in terms of anti-fatigue and humid and heat resistance, and the product will not be able to achieve an ideal service life.

[0013] In some embodiments, the weight parts of the PVC resin are one of 45 parts, 48 parts, 50 parts, 52 parts, 55 parts or the range value of any two of them, the weight parts of the plasticizer are one of 45 parts, 48 parts, 50 parts, 52 parts, 55 parts or the range value of any two of them, the weight parts of the terpolymer are one of 7.5 parts, 8 parts, 10 parts, 12 parts, 15 parts, 17 parts, 19 parts or the range value of any two of them, the weight parts of the nano halloysite are one of 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts or the range value of any two of them, the weight parts of the carbon free radical scavenger are one of 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, 1.1 parts, 1.2 parts, 1.25 parts or the range value of any two of them, and the weight parts of the stabilizer are one of 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts or the range value of any two of them.

[0014] More preferably, the mass ratio of the PVC resin to the plasticizer is 1:(0.8 - 1.25).

[0015] More preferably, the mass content of the PVC resin in the PVC composition is ≥40wt%.

[0016] In the technical solution of the present invention, the product can achieve excellent tensile strength and tear strength when the proportion of the plasticizer in the matrix resin is relatively high, and has strong fatigue resistance and moisture and heat resistance, without considering the application limitations brought by the high-dose plasticizer of the existing products, and has strong practicability.

[0017] Preferably, the apparent density of the PVC resin under GB / T20022-2005 is 0.47 - 0.54g / mL.

[0018] Preferably, the average degree of polymerization of the PVC resin is 1000 - 2000.

[0019] Further preferably, the average degree of polymerization of the PVC resin is one of 1000, 1200, 1300, 1400, 1500, 1800, 2000 or the range value of any two of them.

[0020] Based on the principle of PVC resin selection, there is no special limitation. Based on the processing requirements and application requirements of the product, those skilled in the art can use PVC resins with different degrees of polymerization in combination with plasticizers as long as the mechanical properties, fatigue resistance and moisture and heat resistance of the product are not affected.

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

[0022] Preferably, the plasticizer includes at least one of diisotridecyl phthalate, trioctyl trimellitate, bis(2-propylheptyl) phthalate, and adipic acid polyester plasticizer.

[0023] Based on the product feel requirements, those skilled in the art can use conventional general plasticizers for PVC resin, such as diisotridecyl phthalate, as components. Due to the introduction of the three key functional components of the product of the present invention, the product has more ideal tensile strength and tear strength compared to the existing PVC composite materials prepared using conventional plasticizers and components. As long as the fatigue resistance and damp heat resistance of the product are not affected, the type of plasticizer introduced is not particularly limited.

[0024] Preferably, the average molecular weight of the hydroxybenzoate-type carbon radical scavenger is 450 - 600.

[0025] More preferably, the hydroxybenzoate-type carbon radical scavenger includes at least one of 4-tert-butyl-2-(5-tert-butyl-2-oxo-3H-benzofuran-3-yl)phenyl 3,5-di-tert-butyl-4-hydroxybenzoate and cetadecyl 3,5-di-tert-butyl-4-hydroxybenzoate.

[0026] In the product of the present invention, the role of the hydroxybenzoate-type carbon radical scavenger is very crucial. In addition to scavenging carbon radicals, its special hydroxybenzoate can also achieve good compatibility with PVC resin and avoid precipitation. If other types of radical scavengers are used, it may not be possible to achieve the balance of fatigue resistance and damp heat resistance of the product due to scavenging efficiency or compatibility problems.

[0027] Preferably, the average diameter of the nano halloysite is 30 - 50 nm, and the average length is 0.1 - 1.2 μm.

[0028] Preferably, the average aspect ratio of the nano halloysite is (3 - 25):1.

[0029] More preferably, the average aspect ratio of the nano halloysite is (8 - 15):1.

[0030] It should be noted that the test methods for the average diameter, average length, and average aspect ratio of the nano halloysite of the present invention are as follows: calcine the PVC composition at 800 °C for 30 min in an air atmosphere, sieve out the ash, and then observe it with a scanning electron microscope at a magnification of 30k. Select 200 nano halloysites and measure their diameters and lengths using mapping software, calculate the average value, which is the average diameter and average length, and then calculate the two to obtain the average aspect ratio.

[0031] As described above, nano-halloysite plays a key role in the product. In addition to transmitting external loads and stresses, based on its nanotube structure and aluminosilicate components, it can also absorb corrosive hydrogen chloride gas generated by the degradation of PVC resin to a certain extent, thereby improving the fatigue resistance and damp-heat resistance of the product. When the aspect ratio of nano-halloysite is preferably within the above range, the resulting product can achieve a better dispersion effect, higher stress-bearing strength, better contact effect with PVC resin, and better adsorption effect on by-products, and the comprehensive performance is further improved.

[0032] Preferably, in the PVC composition, the terpolymer, nano-halloysite and carbon radical scavenger are added in the form of masterbatch.

[0033] More preferably, the method for preparing the masterbatch includes the following steps:

[0034] Mix the terpolymer, nano-halloysite and carbon radical scavenger and carry out melt extrusion granulation, and the masterbatch is obtained.

[0035] It should be noted that the masterbatch of the present invention can be prepared by the above conventional direct mixing method, or by other methods, including but not limited to CVD spray modification, etc., as long as it does not affect the subsequent processing of the PVC composition and can achieve the expected functions of the three components in the masterbatch, so that the mechanical, fatigue resistance and damp-heat resistance effects of the final prepared product meet the expectations, there is no limitation.

[0036] Preferably, the stabilizer includes at least one of calcium-zinc stabilizer, organotin stabilizer, and barium-zinc stabilizer.

[0037] Preferably, the components of the PVC composition may also include but are not limited to antistatic agents, lubricants, flame retardants, etc. Based on the processing requirements of those skilled in the art or the actual use of the product, other types of functional additives can be added without affecting the expected performance of the product. For example, the above additives can improve the antistatic ability, processing ability and flame retardancy of the product without affecting the characteristic performance of the product. That is, the description of the components of the technical solution of the present invention is not a limitation on its types.

[0038] Another object of the present invention is also to provide a method for preparing the PVC composition, including the following steps:

[0039] Add each component to a screw extruder and carry out melt extrusion granulation to obtain the PVC composition.

[0040] Preferably, the temperature zones of the screw extruder are set as follows: zone 1: 80 - 120°C, zone 2: 100 - 130°C, zone 3: 100 - 130°C, zone 4: 100 - 130°C, zone 5: 110 - 140°C, zone 6: 110 - 140°C, zone 7: 120 - 150°C, zone 8: 120 - 150°C; the screw rotation speed is 200 - 400 rpm; and the length-diameter ratio is (25 - 30):1.

[0041] Another object of the present invention is to provide the use of the PVC composition in the preparation of outer packaging materials.

[0042] Preferably, the outer packaging materials include cable coating materials, automotive parts, and electrical appliance housings.

[0043] Due to the synergistic effect of the key components, the PVC composition of the present invention can achieve high tensile strength and tear strength even at a relatively thin processing size while introducing a plasticizer to achieve an elastic handfeel. At the same time, it has ideal fatigue resistance and damp heat resistance, and is very suitable for the preparation of outer packaging materials with high requirements for various application indicators in various fields.

[0044] The beneficial effect of the present invention is that the present invention provides a PVC composition. In the matrix system of PVC resin and plasticizer, a terpolymer, a carbon free radical scavenger, and nano-halloysite are introduced as functional components. Based on the synergistic effect of the three, not only can the tensile strength and tear strength of the product be effectively improved, but also it has excellent fatigue resistance and damp heat resistance. The product has a long service life and can meet the performance index requirements of the outer packaging product industry. Detailed Embodiments

[0045] To better illustrate the object, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific examples and comparative examples. The purpose is to understand the content of the present invention in detail, rather than to limit the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention. The experimental reagents and instruments involved in the implementation of the present invention are all common ordinary reagents and instruments unless otherwise specified.

[0046] Examples 1 - 11

[0047] For the examples of the PVC composition of the present invention, the composition components of the PVC composition are shown in Table 1.

[0048] The preparation method of the PVC composition includes the following steps:

[0049] Mix all components evenly, and then melt and extrude and pelletize in a twin-screw extruder to obtain the PVC composition.

[0050] When the components are melt-extruded, the temperature zones of the screw extruder are set as follows: zone 1 at 100 °C, zone 2 at 105 °C, zone 3 at 110 °C, zone 4 at 115 °C, zone 5 at 120 °C, zone 6 at 125 °C, zone 7 at 130 °C, zone 8 at 135 °C. The screw rotation speed is 300 rpm, and the length-diameter ratio is 28:1.

[0051] Example 12

[0052] An example of the PVC composition of the present invention, the composition components of the PVC composition are shown in Table 1.

[0053] The preparation method of the PVC composition includes the following steps:

[0054] Mix the terpolymer, nano-halloysite, and carbon radical scavenger, and then carry out melt extrusion granulation at 100 °C to obtain the masterbatch;

[0055] Mix the masterbatch and the remaining components evenly, and then carry out melt extrusion granulation in a twin-screw extruder to obtain the PVC composition. The temperature zones, rotation speed, and length-diameter ratio of the screw extruder are the same as above.

[0056] Comparative Examples 1-9

[0057] The difference between each comparative example and Example 1 is only the types and ratios of the components, as shown in Table 2.

[0058] Among the components of each example and comparative example,

[0059] The PVC resin 1 is PVC S-80 produced by Formosa Plastics Chemicals, with an average degree of polymerization of 1800;

[0060] The PVC resin 2 is PVC S-70 produced by Formosa Plastics Chemicals, with an average degree of polymerization of 1300;

[0061] The plasticizer 1 is DTDP (di-iso-tridecyl phthalate) produced by Exxon;

[0062] The plasticizer 2 is W2050 (adipic acid polyester plasticizer) produced by DIC;

[0063] The terpolymer 1 is an ethylene-butyl acrylate-carbon monoxide random copolymer (CAS 61843-70-7) produced by DuPont;

[0064] The terpolymer 2 is an ethylene-vinyl acetate-carbon monoxide random copolymer (CAS 26337-35-9) produced by DuPont;

[0065] The terpolymer 3 is ethylene-butyl acrylate-glycidyl methacrylate, PTW, produced by DuPont;

[0066] The purity of the nano halloysite 1 is ≥95%, the average length is 0.4 um, the average diameter is 40 nm, and the average aspect ratio is 10:1;

[0067] The purity of the nano halloysite 2 is ≥95%, the average length is 0.6 um, the average diameter is 42 nm, and the average aspect ratio is 14.2:1;

[0068] The purity of the nano halloysite 3 is ≥95%, the average length is 1 um, the average diameter is 45 nm, and the average aspect ratio is 22.2:1;

[0069] The purity of the nano halloysite 4 is ≥95%, the average length is 0.2 um, the average diameter is 35 nm, and the average aspect ratio is 5.7:1;

[0070] The purity of the nano silica is ≥95%, and the average particle size is 50 nm;

[0071] The purity of the nano hydrotalcite is ≥95%, and the average particle size is 50 nm;

[0072] The carbon radical scavenger 1 is commercially available 4-tert-butyl-2-(5-tert-butyl-2-oxo-3H-benzofuran-3-ylidene)phenyl 3,5-di-tert-butyl-4-hydroxybenzoate, CAS 1261240-30-5, a hydroxybenzoate-type carbon radical scavenger;

[0073] The carbon radical scavenger 2 is commercially available cetadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, CAS 67845-93-6, a hydroxybenzoate-type carbon radical scavenger;

[0074] The carbon radical scavenger 3 is commercially available 4-benzoyloxy-2,2,6,6-tetramethylpiperidine;

[0075] The carbon radical scavenger 4 is commercially available bis(octadecyl)hydroxylamine;

[0076] The stabilizer is PKD-2290 produced by Chemisun, a calcium-zinc stabilizer.

[0077] Unless otherwise specified, the component raw materials used in each example and comparative example of the present invention are all commercially available raw materials, and the component raw materials used in each parallel experiment are all of the same kind. At the same time, for the average length, average diameter, and average aspect ratio of the nano halloysite in the products obtained in each example and comparative example, the above test method is used for testing, and the results are shown in Table 1

[0078] Table 1

[0079]

[0080]

[0081] Table 2

[0082]

[0083] In order to verify the performance of the PVC composition of the present invention, the products prepared in each example and comparative example were subjected to the following performance tests, and the specific steps are as follows:

[0084] (1) Tensile strength test: Test according to GB / T 1040.3-2006;

[0085] (2) Tear strength test: Test according to GB / T 529-2008;

[0086] (3) Fatigue resistance performance test: Referring to GB / T41941-2022 vulcanized rubber, the fatigue crack growth rate of the product was measured. The smaller the growth rate, the better the fatigue resistance performance of the product;

[0087] (4) Damp heat resistance performance test: The elongation at break retention rate of each product before and after aging treatment at 85°C temperature and 85% humidity for 168 h was tested according to step (2), and the retention rate was calculated.

[0088] The test results are shown in Tables 3 and 4.

[0089] Table 3

[0090]

[0091] Table 4

[0092]

[0093] It can be seen from Tables 3 and 4 that the PVC composition of the present invention has ideal mechanical properties, the tensile strength can reach more than 11 MPa, and the tear strength can reach more than 80 N / mm; at the same time, the product is excellent in fatigue resistance and damp heat resistance performance, and the crack growth rate can be maintained at 1*10 -6 mm / cycle or less, and after the "double 85" treatment, the elongation at break retention rate of the product can be maintained at more than 80%. The comprehensive performance is excellent and it is very suitable for use as an outer packaging material.

[0094] In the product of the present invention, in addition to the matrix resin and the plasticizer, the most crucial functional components are the terpolymer, nano halloysite, and a specific type of carbon free radical scavenger. The three work together synergistically to achieve the comprehensive performance of the product, and none of them can be missing. As can be seen from Comparative Example 1, Comparative Example 3, and Comparative Example 6, when one of them is missing or the addition amount is too small, the performance of the product will drop significantly, and it is impossible to balance the mechanical, fatigue resistance, and heat and humidity resistance performance. At the same time, as functional components, the types of the three cannot be randomly replaced with other components having similar functions in the prior art. As shown in Comparative Example 2, Comparative Example 7, and Comparative Example 8, for the selection of the terpolymer and the carbon free radical scavenger, if a conventional terpolymer additive or other types of free radical scavengers are used, the product cannot achieve the same technical effect. For the filler, although nano materials similar to the product solution of the present invention are often used in the existing PVC material system, as shown in Comparative Example 4 and Comparative Example 5, if other types other than nano halloysite are used, it is impossible to achieve the ideal effect of improving the stability of the product under stress and heat and humidity treatment, and the fatigue resistance and heat and humidity resistance of the product cannot be balanced. However, if the introduction amount is too much, as shown in Comparative Example 9, due to the small size of this component, agglomeration is likely to occur, so the performance of the product will instead drop significantly, and thus it cannot meet the performance index requirements.

[0095] As shown in Example 1, Example 8 to Example 10, the aspect ratio of nano halloysite will affect its dispersion effect in the product, and thus affect the degree of load transfer and hydrogen chloride gas capture. When the aspect ratio is preferably (8 - 15):1, the dispersion effect of nano halloysite in the product is better, and the mechanical properties, stress resistance, and heat and humidity resistance of the product are further improved.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A PVC composition, characterized in that, It comprises the following components in parts by weight: 45 - 55 parts of PVC resin, 45 - 55 parts of plasticizer, 7.5 - 19 parts of terpolymer, 2 - 5 parts of nano halloysite, 0.5 - 1.25 parts of carbon free radical scavenger and 5 - 10 parts of stabilizer; The terpolymer includes at least one of ethylene - butyl acrylate - carbon monoxide random copolymer and ethylene - vinyl acetate - carbon monoxide random copolymer; The carbon free radical scavenger includes hydroxybenzoate - type carbon free radical scavenger.

2. The PVC composition according to claim 1, wherein The mass ratio of the PVC resin to the plasticizer is 1:(0.8 - 1.25).

3. The PVC composition according to claim 1, characterized in that, The average degree of polymerization of the PVC resin is 400 - 1200.

4. The PVC composition according to claim 1, wherein The plasticizer includes at least one of diisotridecyl phthalate, trioctyl trimellitate, bis(2 - propylheptyl) phthalate, and adipic acid - based polyester plasticizer.

5. The PVC composition according to claim 1, wherein The average molecular weight of the hydroxybenzoate - type carbon free radical scavenger is 450 - 600; preferably, the hydroxybenzoate - type carbon free radical scavenger includes at least one of 4 - tert - butyl - 2-(5 - tert - butyl - 2 - oxo - 3H - benzofuran - 3 - yl)phenyl 3,5 - di - tert - butyl - 4 - hydroxybenzoate and cetyl 3,5 - di - tert - butyl - 4 - hydroxybenzoate.

6. The PVC composition according to claim 1, wherein The average diameter of the nano halloysite is 30 - 50 nm, and the average length is 0.1 - 1.2 μm.

7. The PVC composition according to claim 6, characterized in that, The average aspect ratio of the nano halloysite is (3 - 25):

1.

8. The PVC composition according to claim 1, characterized in that, In the PVC composition, the terpolymer, nano halloysite and carbon free radical scavenger are added in the form of masterbatch.

9. The preparation method of the PVC composition according to any one of claims 1 to 8, characterized in that, It includes the following steps: Adding each component into a screw extruder for melt extrusion and pelletizing to obtain the PVC composition.

10. An outer packaging material, characterized in that, It includes the PVC composition according to any one of claims 1 - 8.

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