A PVC resin and a method for preparing the same

Abstract

This invention relates to a PVC resin and its preparation method, belonging to the technical field of PVC cable resins. Due to the small molecular weight of the plasticizers added to PVC cables, plasticizers often migrate to the cable surface. Long-term precipitation and migration can cause the wires to harden and become brittle, failing to meet usage requirements and posing safety hazards. The raw materials of this invention include vinyl chloride monomer, dispersant, initiator, water, and terminator. Its key feature is that it also includes a mixed emulsion of trimethylallyl isocyanate and isooctyl acrylate monomers. By not adding the mixed emulsion of trimethylallyl isocyanate and isooctyl acrylate monomers to the PVC resin, the defects of each monomer can be compensated, improving the overall dispersion uniformity, obtaining excellent modification capabilities of trimethylallyl isocyanate and isooctyl acrylate, and improving the oil extraction resistance of the PVC resin.

Description

Technical Field

[0001] A PVC resin and its preparation method are disclosed, belonging to the field of PVC cable material resin technology. Background Technology

[0002] PVC cables are widely used in automotive, marine, computer, office, and household applications due to their advantages such as flexibility, abrasion resistance, high mechanical properties, ease of processing, and cost-effectiveness. However, because the plasticizers added to PVC cables have small molecular weights, they often migrate to the cable surface. Long-term migration and precipitation can cause the wires to harden and become brittle, failing to meet usage requirements and creating safety hazards. Furthermore, due to the oil-soluble nature of plasticizers, contact with the oil phase accelerates their migration, demonstrating their poor oil resistance.

[0003] Polyester plasticizers developed in recent years can significantly improve the problem of plasticizer precipitation, with significantly less precipitation. However, their molecular weight is too large, requiring a long material mixing time in order for the polyester plasticizer to enter the PVC resin particles. Moreover, their high price limits the widespread application of polyester plasticizers. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a PVC resin and its preparation method that do not prolong the mixing time of PVC preparation and can effectively improve the oil resistance.

[0005] The technical solution adopted by the present invention to solve its technical problem is: a PVC resin, the raw materials of which include vinyl chloride monomer, dispersant, initiator, water and terminator, characterized in that: it also includes a mixed emulsion of trimethylallyl isocyanate and isooctyl acrylate monomer.

[0006] Trimethylallyl isocyanate and isooctyl acrylate can both provide excellent oil extraction resistance for PVC resins; however, trimethylallyl isocyanate has a strong copolymerization tendency, which is beneficial for copolymerization with vinyl chloride monomers, and its use in PVC resins or its ability to modify the oil extraction resistance of PVC resins has not yet been found. Isooctyl acrylate is an oil phase and has a strong self-polymerization tendency, which is not conducive to copolymerization with vinyl chloride monomers. This invention adds a mixed emulsion of trimethylallyl isocyanate and isooctyl acrylate monomers to PVC resin, which can precisely compensate for the defects of each of the individual monomers, inhibit the self-polymerization tendency of isooctyl acrylate, and further promote its copolymerization with vinyl chloride monomers. The copolymerization reaction of the components, and the fact that trimethylallyl isocyanate is a solid and cannot be stably dispersed in water, and that isooctyl acrylate oil phase does not tend to disperse in water, can effectively disperse trimethylallyl isocyanate to the oil phase and then to the vinyl chloride monomer, improving the overall dispersion uniformity and greatly shortening the material mixing and dispersion time. This results in the excellent modification ability of trimethylallyl isocyanate and isooctyl acrylate. Both trimethylallyl isocyanate and isooctyl acrylate are polymerized onto the vinyl chloride molecular chain, allowing the PVC molecular chain to simultaneously acquire acrylate and isocyanate functional groups, resulting in a wider range of oil-resistant varieties and better oil resistance, without prolonging the material mixing time.

[0007] The preferred amount of water used is 1 to 2.5 times the weight of the vinyl chloride monomer.

[0008] Preferably, the amount of trimethallyl isocyanate used is 0.5 to 1% of the weight of vinyl chloride monomer.

[0009] Preferably, the amount of isooctyl acrylate used is 0.5 to 1% of the weight of vinyl chloride monomer.

[0010] Preferably, the weight ratio of trimethallyl isocyanate to isooctyl acrylate is 1 to 2:1.

[0011] Isooctyl acrylate and trimethylallyl isocyanate need to complement each other and work synergistically. Excessive amounts of either component will severely inhibit the binding of vinyl chloride monomer, thus affecting the reaction rate. The optimal dosage or ratio can ensure that the dispersing effect of isooctyl acrylate is fully utilized, and that trimethylallyl isocyanate promotes the copolymerization of isooctyl acrylate and vinyl chloride monomer, avoiding self-polymerization and uneven dispersion, effectively improving the oil extraction resistance of PVC resin, and shortening the material mixing time.

[0012] Preferably, the dispersant is a mixture of dispersant KH-20, dispersant L-11 and dispersant E50.

[0013] More preferably, the amounts of dispersant KH-20, dispersant L-11 and dispersant E50 are 0.04~0.05%, 0.04~0.05% and 0.03~0.04% of the weight of vinyl chloride monomer, respectively.

[0014] Preferably, the initiator is a mixture of cumyl peroxynedecanoate and bis(2-ethylhexyl) peroxydicarbonate, wherein the amounts of cumyl peroxynedecanoate and bis(2-ethylhexyl) peroxydicarbonate are 0.005~0.04% and 0.04~0.06% of the weight of vinyl chloride monomer, respectively.

[0015] Preferably, the method for preparing the mixed emulsion of trimethylallyl isocyanate and isooctyl acrylate monomer includes the following steps: heating and melting trimethylallyl isocyanate, adding water in 0.8 to 1.2 times its own weight, adding 3 to 5% by weight of emulsifier of trimethylallyl isocyanate and emulsifying evenly, adding isooctyl acrylate, and emulsifying evenly to obtain the mixed emulsion of trimethylallyl isocyanate and isooctyl acrylate monomer.

[0016] More preferably, the emulsifier is an anionic emulsifier, and more preferably sodium dodecyl sulfate.

[0017] Anionic emulsifiers can be discharged during the preparation of PVC resin through dehydration without affecting the vinyl chloride monomer and modified components. They can effectively improve the mixing uniformity of trimethylallyl isocyanate and isooctyl acrylate monomer mixed emulsions, which is beneficial to improve the dispersion effect of trimethylallyl isocyanate and isooctyl acrylate emulsions, shorten the material mixing time, and improve the oil resistance of PVC resin.

[0018] Preferably, the heating and melting temperature is 85~90℃.

[0019] The preferred temperature can increase the emulsification rate of trimethallyl isocyanate and reduce its effects on itself and isooctyl acrylate, avoiding decomposition or self-polymerization.

[0020] A method for preparing the PVC resin, characterized in that: trimethylallyl isocyanate and isooctyl acrylate are emulsified uniformly to obtain a mixed emulsion of trimethylallyl isocyanate and isooctyl acrylate monomers; vinyl chloride monomer, water, the mixed emulsion of trimethylallyl isocyanate and isooctyl acrylate, and a dispersant are stirred uniformly, and then an initiator is added, and the temperature is raised to 45-50°C to start the polymerization reaction; the reaction is continued until the pressure in the reactor drops by 0.1 MPa, and then a terminator is added to terminate the reaction; the material is discharged, dehydrated, and dried to obtain PVC resin.

[0021] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention adds a mixed emulsion of trimethylallyl isocyanate and isooctyl acrylate monomers to PVC resin, which effectively compensates for the defects of each monomer, inhibits the self-polymerization tendency of isooctyl acrylate, promotes its copolymerization reaction with vinyl chloride monomer, and simultaneously effectively disperses trimethylallyl isocyanate in the oil phase and then in the vinyl chloride monomer, improving the overall dispersion uniformity and significantly shortening the material mixing and dispersion time. This results in excellent modification capabilities of trimethylallyl isocyanate and isooctyl acrylate, improving the oil extraction resistance of PVC resin, and unlike high-molecular-weight polyester plasticizers, it does not prolong the material mixing time. This effectively improves the problem of poor oil extraction resistance of additives in PVC cables, which leads to cable performance degradation, and is particularly suitable for automotive and marine cables. Detailed Implementation

[0022] The present invention will be further described below with reference to embodiments, of which Embodiment 3 is the preferred embodiment. The preparation methods of the PVC resin in the following embodiments and comparative examples include the following steps:

[0023] 1) Melt trimethylallyl isocyanate by heating to 85-90℃, add deionized water of equal weight, add sodium dodecyl sulfate of 3-5% by weight of trimethylallyl isocyanate, emulsify with a high-speed emulsifier for 3-5 minutes until uniform, add isooctyl acrylate, emulsify for 3-5 minutes until uniform, and obtain a mixed emulsion of trimethylallyl isocyanate and isooctyl acrylate monomers.

[0024] 2) The mixed emulsion of trimethylallyl isocyanate and isooctyl acrylate monomer, along with vinyl chloride monomer, dispersant, and deionized water, is added to a 5L polymerization reactor. The mixture is stirred thoroughly at room temperature for 15-30 minutes until homogeneous. An initiator is added and stirred to initiate the polymerization. The reactor is then sealed and heated to 45-55℃ to reach the highest pressure inside. When the pressure inside the reactor drops by 0.1 MPa, a terminator is added to terminate the reaction. The mixture is discharged into a centrifuge for centrifugal dehydration. The dehydrated wet material is then dried in a 60℃ oven to obtain PVC resin.

[0025] In the following examples and comparative examples, TMAIC is trimethylallyl isocyanate and 2-EHA is isooctyl acrylate.

[0026] The dispersants used are KH-20, L-11 and E50; the initiators used are EHP initiator (di(2-ethylhexyl) peroxide dicarbonate) and CNP initiator (isopropylphenyl peroxide neodecanoate); the terminator used is diethylhydroxylamine.

[0027] Example 1

[0028] A PVC resin, wherein the PVC resin raw materials in each embodiment are weighed according to the formulation in Table 1 below.

[0029] Table 1 Formulation of Examples

[0030] .

[0031] Comparative Example

[0032] A PVC resin, the raw materials of each comparative PVC resin are weighed according to the formulation in Table 2 below.

[0033] Table 2 Comparative Formulations

[0034] .

[0035] In Comparative Example 4, the trimethylallyl acrylate and isooctyl acrylate were not emulsified into crystal forms, but were directly introduced into the vinyl chloride monomer.

[0036] Performance testing

[0037] The PVC resins prepared in the above examples and comparative examples were mixed according to the cable material formula. The basic formula of the cable material is 100 parts PVC resin, 8.0 parts calcium-zinc stabilizer, 55 parts plasticizer DOP, 10 parts fine calcium carbonate, 10 parts calcined clay, and 0.5 parts lubricant. The mixed cable material was milled on a two-roll mill at 162℃. The plasticizing roll wrapping time was tested, and the mixture was milled into sheets. The sheets were then hot-pressed into 2mm soft sheets on a press. The 2mm soft sheets were punched to make type 5 tensile test strips. The tensile test strips were immersed in gasoline at 50℃ for 24 hours and then subjected to tensile performance tests together with the unimmersed gasoline samples. The maximum change rate of tensile strength and elongation at break before and after immersion in gasoline was obtained. The test results are shown in Table 3.

[0038] Table 3 Performance Test Results

[0039] .

[0040] As can be seen from the examples and comparative examples, trimethylallyl isocyanate and isooctyl acrylate have a synergistic effect in improving the oil resistance of the special resin. Examples 2 and 4 show that the preparation of the trimethylallyl isocyanate and isooctyl acrylate emulsion significantly improves the oil resistance of the special resin. Example 6 shows that insufficient amounts of dispersants KH-20, L-11, and E50 result in a slightly poor copolymerization effect of trimethylallyl isocyanate, isooctyl acrylate, and vinyl chloride, failing to fully utilize the modifying effect of trimethylallyl isocyanate and isooctyl acrylate, thereby reducing the oil resistance of the special resin and causing a decrease in the tensile properties of the cable material sample after oil immersion.

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A PVC resin, raw materials comprising vinyl chloride monomer, dispersant, initiator, water and terminator, characterized in that: It also includes mixed emulsions of trimethylallyl isocyanate and isooctyl acrylate monomers; The dispersant is a mixture of dispersant KH-20, dispersant L-11 and dispersant E50; The amounts of dispersant KH-20, dispersant L-11, and dispersant E50 are 0.04~0.05%, 0.04~0.05%, and 0.03~0.04% of the weight of vinyl chloride monomer, respectively. The amount of trimethallyl isocyanate used is 0.5-1% of the weight of vinyl chloride monomer; The amount of isooctyl acrylate used is 0.5-1% of the weight of vinyl chloride monomer; The vinyl chloride monomer, water, trimethylallyl isocyanate and isooctyl acrylate emulsion, and dispersant are stirred evenly, and then an initiator is added. The temperature is raised to 45-50℃ to start the polymerization reaction.

2. The PVC resin according to claim 1, characterized in that: The weight ratio of the trimethallyl isocyanate and isooctyl acrylate is 1~2:

1.

3. The PVC resin according to claim 1, characterized in that: The initiator is a mixture of cumyl peroxynedecanoate and bis(2-ethylhexyl) peroxydicarbonate, wherein the amounts of cumyl peroxynedecanoate and bis(2-ethylhexyl) peroxydicarbonate are 0.005~0.04% and 0.04~0.06% of the weight of vinyl chloride monomer, respectively.

4. The PVC resin according to claim 1, characterized in that: The method for preparing the mixed emulsion of trimethylallyl isocyanate and isooctyl acrylate monomer includes the following steps: heating and melting trimethylallyl isocyanate, adding water in 0.8 to 1.2 times its own weight, adding emulsifier in 3 to 5% of the weight of trimethylallyl isocyanate and emulsifying evenly, adding isooctyl acrylate, and emulsifying evenly to obtain the mixed emulsion of trimethylallyl isocyanate and isooctyl acrylate monomer.

5. The PVC resin according to claim 4, characterized in that: The heating and melting temperature is 85~90℃.

6. A method for preparing the PVC resin according to any one of claims 1 to 5, characterized in that: Trimethylallyl isocyanate and isooctyl acrylate were emulsified uniformly to obtain a mixed emulsion of trimethylallyl isocyanate and isooctyl acrylate monomers. Vinyl chloride monomer, water, the mixed emulsion of trimethylallyl isocyanate and isooctyl acrylate, and dispersant were stirred evenly. Then an initiator was added, and the temperature was raised to 45-50°C to start the polymerization reaction. When the pressure in the reactor dropped by 0.1 MPa, a terminator was added to terminate the reaction. The material was discharged, dehydrated, and dried to obtain PVC resin.