A self-extinguishing polyvinyl chloride composite material and its preparation method and application

Abstract

The present invention provides a self-extinguishing polyvinyl chloride composite material, its preparation method, and application, belonging to the technical field of polyvinyl chloride composite material processing. The raw materials for preparing the self-extinguishing polyvinyl chloride composite material of the present invention include: 150-200 parts of polyvinyl chloride resin, 10-20 parts of a composite flame retardant, 20-50 parts of a plasticizer, and 1-5 parts of a stabilizer. The raw materials for preparing the composite flame retardant include magnesium hydroxide and a potassium compound. The potassium ions are blended with the magnesium hydroxide to enhance the flame retardant effect of the composite material while maintaining the material's smoke suppression ability. Without sacrificing safety and environmental friendliness, the self-extinguishing polyvinyl chloride composite material of the present invention is obtained, significantly improving the application value and market competitiveness of polyvinyl chloride composite materials in key fields such as construction, transportation, and electronic and electrical equipment, while also meeting the global demand for high-performance fireproof materials.

Description

Technical Field

[0001] The present invention relates to the technical field of polyvinyl chloride composite material processing, in particular to a self-extinguishing polyvinyl chloride composite material and a preparation method and application thereof. Background Art

[0002] Polyvinyl chloride (PVC), a thermoplastic resin, was once the world's most produced general-purpose plastic. It is ubiquitous in a wide range of applications, including building materials, industrial products, everyday items, floor coverings, tiles, artificial leather, pipes, wire and cable, packaging film, containers, foams, sealants, and fibers. PVC products are renowned for their high dimensional stability, excellent surface finish, water and oil resistance, and exceptional corrosion resistance. However, PVC composites begin to decompose at temperatures around 170°C and exhibit poor stability to light and heat. At temperatures exceeding 100°C or with prolonged exposure to sunlight, the material decomposes to produce hydrogen chloride, which catalyzes further autodecomposition, resulting in color change and a rapid decline in its physical and mechanical properties. Therefore, in practical applications, stabilizers must be added to improve PVC's thermal and light stability.

[0003] In addition, phthalates need to be added to polyvinyl chloride materials to improve their mechanical properties. Although polyvinyl chloride itself has certain flame retardant properties, the addition of phthalates will significantly reduce the flame retardant properties of its composite materials. In view of the high performance requirements of the application industry for polyvinyl chloride composite materials, especially in terms of flame retardancy, antimony trioxide is usually needed to be added as a flame retardant. However, since antimony trioxide is expensive and may produce substances harmful to the environment and personal safety during the flame retardant process, the industry is seeking new flame retardants to replace antimony trioxide. Magnesium hydroxide is regarded as an effective substitute, but the current challenge is that although the addition of magnesium hydroxide can significantly improve the smoke suppression performance of polyvinyl chloride composite materials, its limiting oxygen index is not ideal, which means that its flame retardant ability still needs to be further improved.

[0004] In response to the limitations of magnesium hydroxide in improving the flame retardant properties of polyvinyl chloride composites, the mainstream solution on the market focuses on the use of compounding technology, that is, combining magnesium hydroxide with other types of flame retardants to achieve a synergistic enhancement of the flame retardant properties of polyvinyl chloride composites. However, this approach introduces a new problem: although the flame retardancy of the material can be significantly improved by adding traditional flame retardants and blending them with magnesium hydroxide, the other components in the composite flame retardant will interfere with the smoke suppression effect of magnesium hydroxide, thereby negatively affecting the smoke suppression ability of the composite material. Summary of the Invention

[0005] The purpose of the present invention is to provide a self-extinguishing polyvinyl chloride composite material and its preparation method and application, which can improve the flame retardancy of the polyvinyl chloride composite material while maintaining its smoke suppression ability.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a self-extinguishing polyvinyl chloride composite material, comprising the following raw materials in parts by weight:

[0008] 150-200 parts of polyvinyl chloride resin, 10-20 parts of composite flame retardant, 20-50 parts of plasticizer and 1-5 parts of stabilizer;

[0009] The raw materials for preparing the composite flame retardant include magnesium hydroxide and potassium compounds.

[0010] Preferably, the plasticizer comprises phthalate.

[0011] Preferably, the stabilizer includes one or more of zinc stearate, cadmium stearate, calcium stearate, dibutyltin dilaurate, dibutyltin dimaleate and hydrotalcite calcium zinc stabilizer.

[0012] Preferably, the potassium compound includes one or more of potassium carbonate, potassium perchlorate, potassium chlorate, potassium formate, potassium nitrate, potassium sulfate and potassium hypochlorite.

[0013] Preferably, the mass ratio of the magnesium hydroxide to the potassium compound is 2:8 to 1:9.

[0014] The present invention provides a method for preparing the self-extinguishing polyvinyl chloride composite material described in the above technical solution, comprising the following steps:

[0015] Mixing magnesium hydroxide, a potassium compound and an activator to perform an activation reaction to obtain a composite flame retardant;

[0016] The polyvinyl chloride resin, composite flame retardant, plasticizer and stabilizer are mixed, grafted and plasticized, and extruded to obtain a self-extinguishing polyvinyl chloride composite material.

[0017] Preferably, the activator includes one of ethanol, methanol, propanol or ethylene glycol; the mass of the activator is 10-15% of the total mass of the magnesium hydroxide and the potassium compound.

[0018] Preferably, the activation reaction temperature is 80-130° C., the time is 10-120 min, and the stirring speed is 800-1000 r / min.

[0019] Preferably, the grafting and plasticizing temperature is 30-180° C., the time is 10-90 min, and the stirring speed is 800-1000 r / min.

[0020] The present invention provides the use of the self-extinguishing polyvinyl chloride composite material described in the above technical solution or the self-extinguishing polyvinyl chloride composite material prepared by the preparation method described in the above technical solution in fireproof materials.

[0021] Beneficial effects of the present invention:

[0022] The present invention adds a composite flame retardant to a traditional polyvinyl chloride resin, and the obtained self-extinguishing polyvinyl chloride composite material has good flame retardant properties. The composite flame retardant includes magnesium hydroxide and a potassium compound. Under the catalytic action of potassium ions, the polyvinyl chloride alkane side chains are more easily rearranged and broken, thereby helping the polyvinyl chloride to burn quickly and completely when the surface polyvinyl chloride first contacts the flame, and will not be trapped in incomplete combustion products. More CO2 and water vapor will be generated, and the surrounding heat will be quickly absorbed, so that the ignition point is instantly lowered during the combustion process. At the same time, the combustible gas and the combustion-supporting gas in the air are significantly diluted. By isolating the combustion-supporting gas, the combustion is quenched and quickly reaches a self-extinguishing state, thereby improving the flame retardant effect of the composite material.

[0023] The self-extinguishing polyvinyl chloride composite material prepared by the present invention has a tensile strength of ≥9.60 MPa, an elongation at break ≥165%, a limiting oxygen index ≥27.8, a carbon residue rate ≥70.4%, a maximum smoke density ≤79.66%, and a smoke density grade ≤71.59. While having an excellent flame retardant effect, its smoke suppression ability is also maintained. Moreover, the potassium compound is more advantageous in price than traditional flame retardants such as antimony trioxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the TGA diagram of the pyrolysis of the condensed phase residual carbon layer of the composite material under nitrogen atmosphere due to the change of the composite flame retardant composition. DETAILED DESCRIPTION

[0025] The present invention provides a self-extinguishing polyvinyl chloride composite material, comprising the following raw materials in parts by weight:

[0026] 150-200 parts of polyvinyl chloride resin, 10-20 parts of composite flame retardant, 20-50 parts of plasticizer and 1-5 parts of stabilizer;

[0027] The raw materials for preparing the composite flame retardant include magnesium hydroxide and potassium compounds.

[0028] In the present invention, unless otherwise specified, the raw materials required for preparation are all commercially available products well known to those skilled in the art.

[0029] In the present invention, the mass fraction of the polyvinyl chloride resin is 150 to 200 parts, more preferably 170 to 200 parts; the present invention has no special limitation on the source of the polyvinyl chloride resin, and any commercially available product well known in the art can be used; in an embodiment of the present invention, the polyvinyl chloride resin is preferably derived from Gansu Yinda Chemical Co., Ltd.

[0030] Based on the mass fraction of the polyvinyl chloride resin, the mass fraction of the composite flame retardant of the present invention is preferably 10 to 20 parts, more preferably 10 to 15 parts. The raw materials for preparing the composite flame retardant of the present invention include magnesium hydroxide and a potassium compound; in the present invention, the magnesium hydroxide is preferably ultrafine magnesium hydroxide, and the mesh size of the ultrafine magnesium hydroxide is preferably ≥2000 mesh, more preferably 6000 mesh; the ultrafine magnesium hydroxide is preferably sourced from Jiangxi Guangyuan Chemical Group, with the product number GY-6000; the magnesium hydroxide used in the present invention is an ultra-high mesh magnesium hydroxide product produced by crushing raw ore, has strong hydrophilicity, a large contact area with polyvinyl chloride, and a good modification effect on polyvinyl chloride.

[0031] In the present invention, the potassium compound preferably includes one or more of potassium carbonate, potassium chloride, potassium chlorate, potassium formate, potassium nitrate, potassium sulfate and potassium hypochlorite, and further preferably includes one or more of potassium chlorate, potassium formate, potassium nitrate, potassium sulfate and potassium hypochlorite; when the potassium compound is two or more of the above, the present invention has no special limitation on the ratio of different types of potassium compounds, as long as the mass ratio of magnesium hydroxide to potassium compound is 1:9; the addition of potassium ions can improve the flame retardant properties of the composite material.

[0032] In the present invention, the mass ratio of the magnesium hydroxide to the potassium compound is preferably 2:8 to 1:9, more preferably 1:9.

[0033] Based on the mass fraction of the polyvinyl chloride resin, the mass fraction of the plasticizer in the present invention is preferably 20 to 50 parts, and more preferably 30 to 50 parts; the present invention has no special limitation on the type of the plasticizer, and any plasticizer commonly used in the art can be used; in an embodiment of the present invention, the plasticizer is preferably phthalate, and the phthalate is sourced from Shanghai MacLean Biochemical Technology Co., Ltd.

[0034] Based on the mass fraction of the polyvinyl chloride resin, the mass fraction of the stabilizer of the present invention is preferably 1 to 5 parts, more preferably 2 to 5 parts; the stabilizer preferably includes one or more of zinc stearate, cadmium stearate, calcium stearate, dibutyltin dilaurate, dibutyltin dimaleate and hydrotalcite calcium zinc stabilizer, and further preferably includes one or more of zinc stearate, cadmium stearate, calcium stearate and hydrotalcite calcium zinc stabilizer.

[0035] The present invention provides a method for preparing the self-extinguishing polyvinyl chloride composite material described in the above technical solution, comprising the following steps:

[0036] Mixing magnesium hydroxide, a potassium compound and an activator to perform an activation reaction to obtain a composite flame retardant;

[0037] The polyvinyl chloride resin, composite flame retardant, plasticizer and stabilizer are mixed, grafted and plasticized, and extruded to obtain a self-extinguishing polyvinyl chloride composite material.

[0038] In the present invention, the activator preferably includes one of ethanol, methanol, propanol or ethylene glycol, and is more preferably ethanol; the mass of the activator is preferably 10-15% of the total mass of the magnesium hydroxide and the potassium compound, and is more preferably 10-12%; the activator can activate the surface of the potassium compound and the magnesium hydroxide, and stimulate the combination of the two.

[0039] In the present invention, the activation reaction temperature is preferably 80-130° C., more preferably 90-120° C., the time is preferably 10-120 min, more preferably 10-100 min, and the stirring speed is preferably 800-1000 r / min.

[0040] In the present invention, the temperature of the heating reaction is preferably 30 to 180° C., more preferably 60 to 180° C., the time is preferably 10 to 90 min, more preferably 10 to 55 min, and the stirring speed is preferably 800 to 1000 r / min.

[0041] The present invention provides the use of the self-extinguishing polyvinyl chloride composite material described in the above technical solution or the self-extinguishing polyvinyl chloride composite material prepared by the preparation method described in the above technical solution in fireproof materials.

[0042] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0043] The polyvinyl chloride resin used in Examples 1 to 10 of the present invention and Comparative Examples 1 to 4 was sourced from Gansu Yinda Chemical Co., Ltd.; the magnesium hydroxide used had a mesh size of 6000 and was sourced from Jiangxi Guangyuan Chemical Group with a product number of GY-6000; and the phthalate used was sourced from Shanghai MacLean Biochemical Technology Co., Ltd.

[0044] The potassium compounds and stabilizers used in Examples 1 to 10 of the present invention and Comparative Examples 1 to 4 are all commercially available products, and there is no specific requirement for their sources.

[0045] Example 1

[0046] 18 g of magnesium hydroxide, 2 g of potassium chlorate and 15 mL of ethanol were mixed, and an activation reaction was carried out at 120° C. under stirring conditions of 800 rpm for 10 min to obtain a composite flame retardant;

[0047] The composite flame retardant was mixed with 200 g of polyvinyl chloride resin, 30 g of phthalate and 2 g of hydrotalcite calcium zinc stabilizer, and heated at 170° C. for 15 min under stirring at 800 rpm to obtain the self-extinguishing polyvinyl chloride composite material of Example 1.

[0048] Example 2

[0049] The only difference from Example 1 is that

[0050] The potassium compound used was potassium formate;

[0051] The stabilizer used was zinc stearate;

[0052] The self-extinguishing polyvinyl chloride composite material of Example 2 was obtained.

[0053] Example 3

[0054] The only difference from Example 1 is that

[0055] The potassium compound used is potassium nitrate;

[0056] The stabilizer used was cadmium stearate;

[0057] The self-extinguishing polyvinyl chloride composite material of Example 3 was obtained.

[0058] Example 4

[0059] The only difference from Example 1 is that

[0060] The potassium compound used is potassium sulfate;

[0061] The stabilizer used was calcium stearate;

[0062] The self-extinguishing polyvinyl chloride composite material of Example 4 was obtained.

[0063] Example 5

[0064] The only difference from Example 1 is that

[0065] The potassium compound used is potassium hypochlorite;

[0066] The self-extinguishing polyvinyl chloride composite material of Example 5 was obtained.

[0067] Example 6

[0068] The only difference from Example 1 is that

[0069] The mass of magnesium hydroxide is 9g, the mass of potassium chlorate is 1g, the temperature of the activation reaction is 90℃, and the time is 30min;

[0070] The heating reaction temperature was 150°C and the time was 25 min;

[0071] The self-extinguishing polyvinyl chloride composite material of Example 6 was obtained.

[0072] Example 7

[0073] The only difference from Example 2 is that

[0074] The mass of magnesium hydroxide is 9 g, the mass of potassium formate is 1 g, the activation reaction temperature is 90°C, and the time is 30 min;

[0075] The heating reaction temperature was 150°C and the time was 25 min;

[0076] The self-extinguishing polyvinyl chloride composite material of Example 7 was obtained.

[0077] Example 8

[0078] The only difference from Example 3 is that

[0079] The mass of magnesium hydroxide is 9g, the mass of potassium nitrate is 1g, the temperature of the activation reaction is 90℃, and the time is 30min;

[0080] The heating reaction temperature was 150°C and the time was 25 min;

[0081] The self-extinguishing polyvinyl chloride composite material of Example 8 was obtained.

[0082] Example 9

[0083] The only difference from Example 4 is that

[0084] The mass of magnesium hydroxide is 9g, the mass of potassium sulfate is 1g, the temperature of the activation reaction is 90℃, and the time is 30min;

[0085] The heating reaction temperature was 150°C and the time was 25 min;

[0086] The self-extinguishing polyvinyl chloride composite material of Example 9 was obtained.

[0087] Example 10

[0088] The only difference from Example 5 is that

[0089] The mass of magnesium hydroxide is 9g, the mass of potassium hypochlorite is 1g, the temperature of the activation reaction is 90℃, and the time is 30min;

[0090] The heating reaction temperature was 150°C and the time was 25 min;

[0091] The self-extinguishing polyvinyl chloride composite material of Example 10 was obtained.

[0092] Comparative Example 1

[0093] The only difference from Example 1 is that

[0094] Without adding potassium chlorate, the mass of magnesium hydroxide is 20 g;

[0095] The self-extinguishing polyvinyl chloride composite material of Comparative Example 1 was obtained.

[0096] Comparative Example 2

[0097] The only difference from Example 1 is that

[0098] Without adding potassium chlorate, the mass of magnesium hydroxide is 10 g;

[0099] The self-extinguishing polyvinyl chloride composite material of Comparative Example 2 was obtained.

[0100] Comparative Example 3

[0101] The only difference from Example 1 is that

[0102] Without the addition of magnesium hydroxide, the mass of potassium chlorate is 20 g;

[0103] The self-extinguishing polyvinyl chloride composite material of Comparative Example 3 was obtained.

[0104] Comparative Example 4

[0105] The only difference from Example 1 is that

[0106] Without adding magnesium hydroxide, the mass of potassium chlorate is 10 g;

[0107] The self-extinguishing polyvinyl chloride composite material of Comparative Example 4 was obtained.

[0108] Performance Testing

[0109] The composite materials prepared in Examples 1 to 10 and Comparative Examples 1 to 4 were subjected to performance tests, and the test results are recorded in Table 1:

[0110] (1) Tensile strength and breaking productivity test: Tested in accordance with GB / T10400.1-2018 standard.

[0111] (2) Limiting oxygen index test: Tested in accordance with GB / T2406.2-2009 standard.

[0112] (3) Determination of residual carbon rate: Take the standard sample in (1) and weigh it before combustion. After the combustion test is completed, weigh the remaining mass. The residual carbon rate is calculated by the ratio of the remaining mass to the initial mass.

[0113] (4) Maximum smoke density and smoke density level test: Tested in accordance with GB / T8627-2007 standard.

[0114] Table 1 Test results of composite materials obtained from Examples 1 to 10 and Comparative Examples 1 to 4

[0115]

[0116]

[0117] The results of Example 1 and Comparative Examples 1 and 3 show that when one of the composite flame retardant components is missing, the flame retardant and mechanical properties of the polyvinyl chloride composite material differ significantly. This indicates that there is a significant synergistic flame retardant effect between magnesium hydroxide and the potassium compound, and that the potassium compound requires magnesium hydroxide in combination to exhibit a significant flame retardant effect. This indicates that the catalytic flame retardant effect of the potassium compound is synergistic, with magnesium hydroxide serving as the primary flame retardant. When the composite flame retardant is added, the flame retardant and mechanical properties of the polyvinyl chloride composite material are significantly enhanced, with significant improvements in the limiting oxygen index, carbon residue, tensile strength, and elongation at break.

[0118] After the smoke density level and maximum smoke density tests were conducted on the samples, the condensed phase carbon residue layer of the samples was collected. Under a nitrogen atmosphere, the mass changes of the condensed phase carbon residue layer of the self-extinguishing polyvinyl chloride composite material prepared by the composite flame retardant in Example 1, the magnesium hydroxide alone in Comparative Example 1, and the potassium compound alone in Comparative Example 3 at different temperatures were measured using a thermogravimetric analyzer to obtain the following: Figure 1 .from Figure 1 It can be seen that there are differences in the pyrolysis curves of the three. The pyrolysis curves of only one of them as a flame retardant are similar, and the residual carbon rate is low; while the composite material with the composite flame retardant has a higher residual carbon rate. This is because the composite flame retardant can catalyze the recombination and breakage of the high molecular alkane molecular chain during the combustion process, thereby completely burning to produce CO2 and H2O, resulting in self-extinguishing phenomenon and maintaining a high residual carbon rate; at the same time, the two synergistically act as flame retardants, quenching the flame in a short period of time while forming a series of physical barriers with magnesium oxide as the main body to isolate the continued spread of combustion; potassium compounds are environmentally friendly and more affordable than traditional flame retardants such as antimony trioxide while maintaining excellent flame retardant properties. They can broaden the application of potassium compound catalytic flame retardancy and further obtain polyvinyl chloride composite materials with even better flame retardant properties.

[0119] It can be seen from the above embodiments that the present invention provides a self-extinguishing polyvinyl chloride composite material with a tensile strength ≥9.60 MPa, an elongation at break ≥165%, a limiting oxygen index ≥27.8, a carbon residue rate ≥70.4%, a maximum smoke density ≤79.66%, and a smoke density level ≤71.59. While not affecting the smoke suppression effect, the present invention significantly improves its flame retardant properties, making it have high added value and further expanding the application field of polyvinyl chloride composite materials.

[0120] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A self-extinguishing polyvinyl chloride composite material, characterized in that: The preparation comprises the following raw materials in parts by weight: 150-200 parts of polyvinyl chloride resin, 10-20 parts of composite flame retardant, 20-50 parts of plasticizer and 1-5 parts of stabilizer; The raw materials for preparing the composite flame retardant include magnesium hydroxide and potassium compounds; The potassium compound includes one or more of potassium carbonate, potassium chloride, potassium chlorate, potassium formate, potassium nitrate, potassium sulfate and potassium hypochlorite; The preparation method of the composite flame retardant comprises the following steps: mixing magnesium hydroxide, a potassium compound and an activator, performing an activation reaction, and obtaining the composite flame retardant; The mass ratio of the magnesium hydroxide to the potassium compound is 2:8 to 1:9; The activator includes one of ethanol, methanol, propanol or ethylene glycol; the mass of the activator is 10-15% of the total mass of the magnesium hydroxide and the potassium compound; The activation reaction temperature is 80-130° C., the time is 10-120 min, and the stirring speed is 800-1000 r / min.

2. The self-extinguishing polyvinyl chloride composite material according to claim 1, characterized in that: The plasticizers include phthalates.

3. The self-extinguishing polyvinyl chloride composite material according to claim 1, characterized in that: The stabilizer includes one or more of zinc stearate, cadmium stearate, calcium stearate, dibutyltin dilaurate, dibutyltin dimaleate and hydrotalcite calcium zinc stabilizer.

4. The method for preparing the self-extinguishing polyvinyl chloride composite material according to any one of claims 1 to 3, characterized in that: The following steps are involved: Mixing magnesium hydroxide, a potassium compound and an activator to perform an activation reaction to obtain a composite flame retardant; The polyvinyl chloride resin, composite flame retardant, plasticizer and stabilizer are mixed, grafted and plasticized, and extruded to obtain a self-extinguishing polyvinyl chloride composite material.

5. The preparation method according to claim 4, characterized in that The grafting and plasticizing temperature is 30-180° C., the time is 10-90 min, and the stirring speed is 800-1000 r / min.

6. Use of the self-extinguishing polyvinyl chloride composite material according to any one of claims 1 to 3 or the self-extinguishing polyvinyl chloride composite material prepared by the preparation method according to any one of claims 4 to 5 in fireproof materials.

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