Moisture-proof and dry-free PVC modified material and preparation method thereof

Abstract

The application discloses a kind of damp-proofing dry-free PVC modified materials and preparation method thereof, belong to plastic processing technical field, including the following steps: input PVC, double grafting EPDM and fluorine-containing ester polyolefin wax hot mix, then continue to mix material by adding filler, tributyl citrate, dispersing agent, lubricant and stabilizer, after melt extrusion granulation, preparation obtains damp-proofing dry-free PVC modified material.The application introduces double grafting EPDM and fluorine-containing ester polyolefin wax in PVC system, double grafting EPDM and fluorine-containing ester polyolefin wax can effectively synergize heavy calcium carbonate and KH550-CeO2 from material level, build continuous hydrophobic protective layer and flame-retardant layer on particle surface, inhibit moisture adsorption from source, so that the obtained PVC modified material has the technical advantages of no need for pre-drying, long-term damp-proof stable storage.

Description

Technical Field

[0001] This invention relates to the field of plastic processing technology, and more specifically, to a moisture-proof, drying-free modified PVC material and its preparation method. Background Technology

[0002] In the processing and production of polyvinyl chloride (PVC) materials, the quality of raw materials is a key factor affecting product quality. However, raw materials are easily affected by regional humidity differences during transportation and storage, especially in southern regions where raw materials are more prone to absorbing moisture. This can lead to quality defects such as roughness and bubbling in finished products, significantly impacting product quality, production costs, and production continuity. Currently, the industry commonly addresses this issue by adding drying equipment, but this approach suffers from problems such as long low-temperature drying times and untimely material supply, hindering overall workshop capacity and resulting in some wasted production costs.

[0003] Currently, the mainstream modified materials on the market are mainly PVC granules. The industry typically uses pre-drying processes to remove moisture from raw materials. Conventional filler-modified systems struggle to inhibit moisture absorption at the source, failing to achieve long-term moisture protection and exhibiting poor storage stability. Furthermore, PVC is prone to thermal agglomeration during blending, further impacting its moisture-proof performance. Introducing modified materials that reduce PVC thermal agglomeration could potentially improve the overall performance of PVC composites. Therefore, developing a PVC modified material that fundamentally inhibits moisture absorption, requires no pre-drying, and offers stable storage is of significant practical importance for simplifying production processes, reducing production costs, and improving processing stability and product quality. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a moisture-proof, drying-free modified PVC material and its preparation method.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A moisture-proof and drying-free modified PVC material, by weight, comprises the following raw materials: 50-56% PVC, 2-3% double-grafted EPDM rubber, 25-30% filler, 5-7% tributyl citrate, 0.6-0.9% dispersant, 1.0-1.4% lubricant, 0.5-1.0% stabilizer, and the balance being fluorinated ester polyolefin wax.

[0007] Furthermore, the preparation method of double-grafted EPDM rubber includes:

[0008] (1) EPDM rubber is grafted copolymerized with maleic anhydride under the initiation of dicumyl peroxide to obtain grafted products;

[0009] (2) Dissolve the grafted product in xylene, add N-methyl-1,3-propanediamine, L-lactide and stannous octoate, react, precipitate with acetone, filter, and dry under vacuum to obtain the double-grafted copolymer.

[0010] (3) Dissolve the double-grafted copolymer in butyl acetate, add bromobutane, seal the reaction, after the reaction is complete, add diethyl ether to precipitate, filter, wash, and vacuum dry to finally obtain double-grafted EPDM rubber.

[0011] Further, in step (1), the mass ratio of maleic anhydride, dicumyl peroxide and ethylene propylene diene monomer (EPDM) is (1-4):(0.03-0.05):(96-98).

[0012] Further, in step (2), the ratio of the amount of graft product, xylene, N-methyl-1,3-propanediamine, L-lactide, stannous octoate and acetone is (0.8-1.0) g : (40-60) mL : (0.1-0.3) g : (0.4-0.6) g : (0.01-0.02) g : (180-220) mL, and the reaction conditions are 110-130℃ for 2-4 h.

[0013] Furthermore, in step (3), the ratio of the amount of double-grafted copolymer, butyl acetate and bromobutane is (0.5-1.5) g: (20-40) mL: (1-3) mL, and the reaction conditions are 50-70℃ for 10-14 h.

[0014] A method for preparing a moisture-proof, no-drying-required modified PVC material includes the following steps:

[0015] PVC, double-grafted EPDM rubber, and fluorinated ester polyolefin wax are hot-mixed, and then fillers, tributyl citrate, dispersants, lubricants, and stabilizers are added and the mixture is continued. After that, the mixture is melt-extruded and granulated to prepare a moisture-proof, drying-free modified PVC material.

[0016] Furthermore, the hot mixing temperature is 40-50℃, and the mixing temperature is 100-130℃.

[0017] Furthermore, the molding process conditions are: barrel temperature 185-195℃, confluence core temperature 160-180℃, mold temperature 180-185℃, and die temperature 190-200℃.

[0018] In summary, the present invention has the following beneficial effects:

[0019] This invention introduces double-grafted EPDM rubber and fluorinated ester polyolefin wax into the PVC system. The double-grafted EPDM rubber and fluorinated ester polyolefin wax can effectively synergize with heavy calcium carbonate and KH550-CeO2 at the material level to construct a continuous hydrophobic protective layer and flame retardant layer on the particle surface, inhibiting moisture adsorption from the source. This gives the resulting modified PVC material the technical advantage of not requiring pre-drying and being able to be stored stably in a moisture-proof manner for a long time. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] The present invention discloses a moisture-proof, drying-free modified PVC material, which comprises, by weight 100%, the following raw materials:

[0022] 50-56% PVC, 2-3% double-grafted EPDM rubber, 25-30% filler, 5-7% tributyl citrate, 0.6-0.9% dispersant, 1.0-1.4% lubricant, 0.5-1.0% stabilizer, with the balance being fluorinated ester polyolefin wax.

[0023] The present invention discloses a method for preparing a moisture-proof, drying-free modified PVC material, the preparation method being as follows:

[0024] (1) EPDM rubber is graft copolymerized with maleic anhydride under the initiation of dicumyl peroxide to obtain grafted products. The mass ratio of maleic anhydride, dicumyl peroxide and EPDM rubber is (1-4):(0.03-0.05):(96-98).

[0025] The grafted product was dissolved in xylene, and N-methyl-1,3-propanediamine, L-lactide and stannous octoate were added. The mixture was heated to 120℃ and reacted for 3 hours. After the reaction was completed, the product was poured into acetone to precipitate the precipitate. The precipitate was filtered and dried under vacuum to obtain the double-grafted copolymer. The ratio of the amount of grafted product, xylene, N-methyl-1,3-propanediamine, L-lactide, stannous octoate and acetone was (0.8-1.0) g : (40-60) mL : (0.1-0.3) g : (0.4-0.6) g : (0.01-0.02) g : (180-220) mL.

[0026] The double-grafted copolymer was dissolved in butyl acetate, and bromobutane was added. The mixture was transferred to a sealed pressure-resistant tube and reacted at 60°C for 12 hours. After the reaction was completed, the solution was dropped into diethyl ether to precipitate the precipitate. The precipitate was filtered and washed with anhydrous diethyl ether. The precipitate was then dried under vacuum at 60°C to obtain double-grafted EPDM rubber. The ratio of the amount of double-grafted copolymer, butyl acetate and bromobutane was (0.5-1.5) g: (20-40) mL: (1-3) mL.

[0027] (2) PVC, double-grafted EPDM rubber and fluorinated ester polyolefin wax are added and hot-mixed at a temperature of 40-50℃ and a mixing temperature of 100-130℃. Then filler, tributyl citrate, dispersant, lubricant and stabilizer are added and the mixture is continued. After that, melt extrusion granulation is carried out. The molding processing conditions are: barrel temperature 185-195℃, confluence core temperature 160-180℃, mold temperature 180-185℃, and die temperature 190-200℃. Moisture-proof and drying-free modified PVC material is prepared.

[0028] Example 1

[0029] A moisture-proof, no-drying-required modified PVC material, comprising the following raw materials by weight (100%):

[0030] 53% PVC (Tianjin Dagu Chemical Co., Ltd., model: DG800), 3% double-grafted EPDM rubber, 30% filler (25% heavy calcium carbonate + 5% KH550-CeO2), 7% tributyl citrate, 0.8% dispersant (vinyl bis-stearamide), 1.2% lubricant (monoglycerate), 1.0% stabilizer (calcium stearate), 4.0% fluorinated ester polyolefin wax (prepared according to the preparation method of Example 1 in the patent publication number JP1990173006A, see paragraph 0024 of its specification).

[0031] A method for preparing a moisture-proof, no-drying modified PVC material:

[0032] (1) Preparation method of double-grafted EPDM rubber:

[0033] Weigh out 2% maleic anhydride, 0.04% dicumyl peroxide initiator, and 97.96% ethylene propylene diene monomer (EPDM) rubber by weight (100%).

[0034] EPDM rubber and initiator were added to a rotary evaporator for vacuum rotary evaporation pretreatment. The water bath temperature of the rotary evaporator was 60℃, the rotary evaporation time was 1 hour, and the rotary evaporation speed was 60 rpm, allowing the initiator to penetrate into the EPDM rubber. Using the pretreated EPDM rubber as raw material and maleic anhydride as grafting monomer, the mixture was uniformly mixed and then added to a torque rheometer for melt blending to obtain the grafted product. During the melt blending process, a torque rheometer was used for melt blending, with all three temperature stages at 180℃, a rotation speed of 30 rpm, and a blending grafting time of 4 minutes.

[0035] The grafted product was dissolved in xylene and heated to 60°C until completely dissolved. N-methyl-1,3-propanediamine, L-lactide, and stannous octoate were added, and the mixture was heated to 120°C and reacted for 3 hours. The reaction solution was poured into acetone to precipitate the precipitate, which was then filtered and dried under vacuum to obtain the double-grafted copolymer. The ratio of grafted product, xylene, N-methyl-1,3-propanediamine, L-lactide, stannous octoate, and acetone was 0.95 g: 50 mL: 0.25 g: 0.5 g: 0.01 g: 200 mL.

[0036] The double-grafted copolymer was dissolved in butyl acetate, and bromobutane was added. The mixture was transferred to a sealed pressure-resistant tube and reacted at 60°C for 12 hours. After the reaction was completed, the solution was dropped into diethyl ether to precipitate the precipitate. The precipitate was filtered and washed with anhydrous diethyl ether. The precipitate was then dried under vacuum at 60°C to obtain double-grafted ethylene propylene diene monomer (EPDM) rubber. The ratio of double-grafted copolymer, butyl acetate, and bromobutane was 1.0 g: 30 mL: 2 mL.

[0037] (2) Preparation method of KH550-CeO2:

[0038] Add KH550 to deionized water at a mass ratio of 0.15:4, and adjust the pH to 3 with glacial acetic acid to obtain the hydrolysate of KH550.

[0039] Nano CeO2 was added to an ethanol-water mixture (ethanol to water mass ratio of 1:1), with the ratio of KH550, nano CeO2 and ethanol-water mixture being 0.15 g: 5 g: 200 mL. The mixture was ultrasonically dispersed for 30 min to prepare a CeO2 dispersion. Hydrolysate of KH550 was added, and the mixture was reacted at 80 °C for 4 h. After the reaction was completed, the mixture was centrifuged, washed three times with anhydrous ethanol to remove unloaded KH550 from the surface, dried, and ground to obtain KH550-CeO2.

[0040] (3) Add PVC, double-grafted EPDM rubber and fluorinated ester polyolefin wax to 45°C, then add heavy calcium carbonate, KH550-CeO2, tributyl citrate, dispersant, lubricant and stabilizer, mix to 115°C, and process by molding extrusion (barrel temperature 190°C, sprue temperature 170°C, die temperature 185°C, die temperature 195°C) to prepare granules.

[0041] Comparative Example 1

[0042] The PVC modified material was prepared according to the method of Example 1, except that 3% of double-grafted EPDM rubber was not added, and the mass fraction of PVC was adjusted to 56%.

[0043] Comparative Example 2

[0044] The PVC modified material was prepared according to the method of Example 1, except that 4% of fluorinated ester polyolefin wax was not added, the mass fraction of PVC was adjusted to 57%, and the rest remained unchanged.

[0045] Comparative Example 3

[0046] The PVC modified material was prepared according to the method of Example 1, except that 5% KH550-CeO2 was not added, all fillers were heavy calcium carbonate with a filler mass fraction of 30%, and the rest remained unchanged.

[0047] Table 1 shows the performance test results of the PVC modified materials prepared by the methods of Example 1 and Comparative Examples 1-3.

[0048] Table 1

[0049]

[0050] Moisture content was determined according to GB / T 6284-2006 "General Method for Determination of Moisture in Chemical Products - Loss on Drying Method"; hygroscopic properties were determined according to GB / T 1034-2008 "Determination of Water Absorption of Plastics"; impact strength was determined according to GB / T1843-2008 "Determination of Cantilever Beam Impact Strength of Plastics"; limiting oxygen index was determined according to GB / T 2406.2-2009 "Determination of Combustion Behavior by Oxygen Index Method for Plastics - Part 2: Room Temperature Test".

[0051] The above description is only a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions that fall within the scope of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A moisture-proof, no-drying-required modified PVC material, characterized in that, Based on 100% by weight, it includes the following raw materials: 50-56% PVC, 2-3% double-grafted EPDM rubber, 25-30% filler, 5-7% tributyl citrate, 0.6-0.9% dispersant, 1.0-1.4% lubricant, 0.5-1.0% stabilizer, and the balance is fluorinated ester polyolefin wax.

2. The moisture-proof, no-drying-required modified PVC material according to claim 1, characterized in that, The preparation method of double-grafted EPDM rubber includes the following steps: (1) EPDM rubber is grafted copolymerized with maleic anhydride under the initiation of dicumyl peroxide to obtain grafted products; (2) Dissolve the grafted product in xylene, add N-methyl-1,3-propanediamine, L-lactide and stannous octoate, react, precipitate with acetone, filter, and dry under vacuum to obtain the double-grafted copolymer. (3) Dissolve the double-grafted copolymer in butyl acetate, add bromobutane, seal the reaction, after the reaction is complete, add diethyl ether to precipitate, filter, wash, and vacuum dry to finally obtain double-grafted EPDM rubber.

3. The moisture-proof, no-drying-required modified PVC material according to claim 2, characterized in that, In step (1), the mass ratio of maleic anhydride, dicumyl peroxide and ethylene propylene diene monomer (EPDM) rubber is (1-4):(0.03-0.05):(96-98).

4. The moisture-proof, no-drying-required modified PVC material according to claim 2, characterized in that, In step (2), the ratio of the amount of graft product, xylene, N-methyl-1,3-propanediamine, L-lactide, stannous octoate and acetone is (0.8-1.0) g : (40-60) mL : (0.1-0.3) g : (0.4-0.6) g : (0.01-0.02) g : (180-220) mL, and the reaction conditions are 110-130℃ for 2-4 h.

5. The moisture-proof, no-drying-required modified PVC material according to claim 2, characterized in that, In step (3), the ratio of double-grafted copolymer, butyl acetate and bromobutane is (0.5-1.5) g: (20-40) mL: (1-3) mL, and the reaction conditions are 50-70℃ for 10-14 h.

6. A method for preparing the moisture-proof, drying-free modified PVC material according to claim 1, characterized in that, PVC, double-grafted EPDM rubber, and fluorinated ester polyolefin wax are hot-mixed, and then fillers, tributyl citrate, dispersants, lubricants, and stabilizers are added and the mixture is continued. After that, the mixture is melt-extruded and granulated to prepare a moisture-proof, drying-free modified PVC material.

7. The preparation method of a moisture-proof, drying-free modified PVC material according to claim 6, characterized in that, The hot mixing temperature is 40-50℃, and the mixing temperature is 100-130℃.

8. The method for preparing a moisture-proof, drying-free modified PVC material according to claim 6, characterized in that, The molding process conditions are: barrel temperature 185-195℃, confluence core temperature 160-180℃, mold temperature 180-185℃, and die temperature 190-200℃.

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