Flame-retardant abs composition and method for producing the same

Abstract

The application relates to the technical field of fireproof materials, in particular to a flame-retardant ABS composition and a preparation method thereof; the flame-retardant ABS composition comprises the following components in parts by weight: ABS particles 1000-1400 parts, polysiloxane 350-450 parts, dimethyl silicone oil 100-200 parts, a flame retardant 300-600 parts, inorganic fillers 100-300 parts, a crosslinking agent 5-40 parts, a coupling agent 2-20 parts, a catalyst 0.5-2 parts and an intumescent agent 1-2 parts; the ABS particles in the composition serve as the only hard aggregate, have high size consistency and the same density, and are not prone to sedimentation; the ABS particles are light and rigid, are not prone to brittle fracture after being extruded, and have flame-retardant properties; when being pushed to an ignition point, the ABS particles can cover the fire source together with the gel, so that the purpose of blocking combustion is achieved.

Description

Technical Field

[0001] This invention relates to the field of fire-retardant materials technology, and in particular to a flame-retardant ABS composition and its preparation method. Background Technology

[0002] Wood materials may spontaneously combust in hot weather. Generally, there are three reasons for this: first, there are decayed pores inside; second, flammable gases (such as methane) are produced inside the pores due to fermentation by bacteria and fungi; and finally, the pores are connected to the outside, allowing air to enter and fuel the combustion of flammable gases. Additionally, rainwater can easily enter, further intensifying the fermentation process.

[0003] Chinese patent discloses a flame-retardant composition and its preparation method, authorization announcement number 116376217B. It describes a flame-retardant composition comprising the following active ingredients by weight: 35-55 parts filler; 30-40 parts lubricant; 5-10 parts oxygen depleting agent; 5-10 parts expanding agent; 6-8 parts plasticizer; the filler being river sand and foamed phenolic resin particles. The foamed phenolic resin particles contain 15-25 wt% expanded graphite. 1. Before curing, the lubricant helps the rough-surfaced filler to smoothly enter the tree cavity. After curing, the filler forms a skeleton, and the shaping agent better connects adjacent fillers and other components, making the composition a solid object that adapts to the shape of the tree cavity's internal space. 2. The gaps between the fillers in this flame-retardant composition contain oxygen-consuming agents and expanding agents, preventing them from contacting the outside environment. When the tree cavity catches fire, the expanding agent, when heated, breaks the fragile adhesive structure between adjacent fillers. The oxygen-consuming agent consumes some oxygen and produces carbon dioxide. The collapsed filler, propelled by the expanding agent, rushes towards the fire, ultimately playing a flame-retardant role. 3. The fillers in this flame-retardant composition are river sand and foamed phenolic resin particles. The river sand provides support and fills the cavity, forming gaps to accommodate the oxygen-consuming agents and expanding agents. The foamed phenolic resin particles have good tensile and ductile properties, suitable for the deformation of the tree cavity space during tree growth, maintaining a large filling degree. Furthermore, the foamed phenolic resin particles have good water absorption, which helps the tree maintain internal moisture and transport.

[0004] In short, existing technology uses an expanding agent heated to push river sand or high-temperature resistant plastic granules toward the ignition point, thus achieving a flame-retardant effect. However, the disadvantages are also obvious: 1) The density difference between river sand and foamed phenolic resin granules is huge, and relying solely on a small amount of shaping agent (sodium stearate) cannot prevent the river sand from settling; 2) The shaping agent (sodium stearate) is soluble in water, and in rainy conditions, the shaping agent may dissolve, causing the flame-retardant structure to collapse as a whole; 3) Foamed phenolic resin granules are hygroscopic, but their water absorption rate is only 2%-3% of their own volume, making it difficult to effectively dry the inside of the pores. Therefore, bacteria can easily grow inside the pores after rainy weather, further rotting the wood. Summary of the Invention

[0005] In view of the shortcomings of the prior art, one of the objectives of the present invention is to provide a flame-retardant ABS composition, and another objective of the present invention is to provide a method for preparing a flame-retardant ABS composition.

[0006] One of the objectives of this invention is achieved through the following technical solution:

[0007] A flame-retardant ABS composition is prepared from the following raw materials in parts by weight:

[0008] The ingredients include 1000-1400 parts ABS granules, 350-450 parts polysiloxane, 100-200 parts dimethyl silicone oil, 300-600 parts flame retardant, 100-300 parts inorganic filler, 5-40 parts crosslinking agent, 2-20 parts coupling agent, 0.5-2 parts catalyst, and 1-2 parts expanding agent.

[0009] Specifically, the ABS granules are made of V0-grade flame-retardant ABS resin, possessing high-temperature resistance and flame-retardant properties.

[0010] Specifically, the ABS particles have a particle size of 0.25 cm. Particles that are too large are not easily propelled by the expanding agent, while particles that are too small increase the difficulty of processing.

[0011] Specifically, the polysiloxane is composed of 2000 viscous α,ω-dihydroxy polydimethylsiloxane and 50000 viscous α,ω-dihydroxy polydimethylsiloxane mixed in a weight ratio of 5:1.

[0012] Specifically, the dimethyl silicone oil is 100% dimethyl silicone oil, the flame retardant is aluminum hydroxide, the inorganic filler is light calcium carbonate, the crosslinking agent is methyltrimethoxysilane, the coupling agent is KH-570, and the catalyst is dibutyltin dilaurate.

[0013] Specifically, the expanding agent is Artemisia argyi. Artemisia argyi has an extremely strong ability to absorb and expand after rain, reaching thousands of times its original volume. Aluminum hydroxide absorbs heat to generate water, which not only cools and retards the flame but also allows the expanding agent to expand rapidly, thus propelling ABS particles and other materials towards the ignition point. Furthermore, in rainy environments, Artemisia argyi can prevent rainwater from flowing into the pores through its absorption and expansion effect, reducing internal decay of the wood.

[0014] The second objective of this invention is achieved through the following technical solution:

[0015] A method for preparing a flame-retardant ABS composition includes the following steps:

[0016] Step 1: Add polysiloxane, dimethyl silicone oil, flame retardant and inorganic filler to a double planetary mixer and disperse them under vacuum heating and stirring.

[0017] Step 2: After cooling to 25°C, nitrogen gas is introduced to standard atmospheric pressure. Then, an expanding agent, crosslinking agent, coupling agent, and catalyst are added to the nitrogen atmosphere and dispersed at high speed to obtain a colloid.

[0018] Step 3: Add ABS particles to a nitrogen atmosphere and stir at low speed to obtain the composition.

[0019] Specifically, the vacuum heating, stirring, and dispersion parameters are: temperature 110℃, vacuum degree -0.05MPa, and rotation speed 1400rpm for 2 hours.

[0020] Specifically, the high-speed dispersion parameters are: 1400 rpm for 20 minutes.

[0021] Specifically, the low-speed stirring parameters are a rotation speed of 50-150 rpm and stirring for 15-45 minutes.

[0022] The composition obtained by this invention can be used to fill cavities in wood materials (wood or trees), and its effects are: 1) to quickly extinguish the fire source in the spontaneous combustion of the cavity, thereby retarding the flame; 2) to reduce rainwater entering the cavity, thereby preventing corrosion.

[0023] The beneficial effects of this invention are as follows: ABS particles in the composition are the only hard aggregate, with high size uniformity and uniform density, and are not prone to settling; ABS particles themselves are lightweight and rigid, and are not easily brittle after being squeezed; in addition, their material has flame-retardant properties, and when pushed to the ignition point, they can cover the fire source together with the colloid, thereby achieving the purpose of blocking combustion; the composition also has swelling capacity, and in rainy environments, the composition located at the opening of the hole can absorb rainwater to block the opening and prevent more rainwater from entering the hole. Detailed Implementation

[0024] The following is a further explanation with reference to specific implementation methods:

[0025] The formulations of Examples 1-3 and Comparative Examples 1-2 are shown in Table 1.

[0026] Table 1 Formulations for each embodiment and comparative example

[0027] Flame retardant composition types Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 ABS granules (parts by weight) 1000 1200 1400 1200 1200 Polysiloxane (parts by weight) 350 400 450 400 400 Dimethyl silicone oil (parts by weight) 100 150 200 150 150 Aluminum hydroxide (parts by weight) 300 400 600 0 400 Ammonium polyphosphate (parts by weight) 0 0 0 400 0 Light calcium carbonate (parts by weight) 100 200 300 200 200 Methyltrimethoxysilane (parts by weight) 5 15 40 15 15 KH-570 (parts by weight) 2 10 20 10 10 Dibutyltin dilaurate (parts by weight) 0.5 1 2 1 1 Artemisia argyi gum (parts by weight) 1 1.5 2 1.5 0 IFR (parts by weight) 0 0 0 0 1.5

[0028] The ABS granules are V0-grade flame-retardant ABS resin with a particle size of 0.25 cm. The polysiloxane is a mixture of 2000 viscous α,ω-dihydroxypolydimethylsiloxane and 50000 viscous α,ω-dihydroxypolydimethylsiloxane at a weight ratio of 5:1. The dimethyl silicone oil is 100 viscous dimethyl silicone oil. The IFR is Unod IFR09.

[0029] The preparation methods of Examples 1-3 and Comparative Examples 1-2 are as follows:

[0030] Step 1: Weigh the raw materials according to the formula in Table 1, and add polysiloxane, dimethyl silicone oil, flame retardant (aluminum hydroxide or ammonium polyphosphate) and inorganic filler (light calcium carbonate) to a double planetary mixer. Disperse under vacuum heating and stirring. The vacuum heating and stirring parameters are: temperature 110℃, vacuum degree -0.05MPa, and rotation speed 1400rpm for 2 hours.

[0031] Step 2: After cooling to 25°C, nitrogen gas is introduced to standard atmospheric pressure. Then, an expanding agent (either Artemisia argyi or IFR), a crosslinking agent (methyltrimethoxysilane), a coupling agent (KH-570), and a catalyst (dibutyltin dilaurate) are added to the nitrogen atmosphere and dispersed at high speed to obtain a colloid. The high-speed dispersion parameters are 1400 rpm for 20 min.

[0032] Step 3: Add ABS particles to a nitrogen atmosphere and stir at low speed to obtain the composition. The low-speed stirring parameters are 100 rpm for 30 minutes.

[0033] Water blocking experiment

[0034] To verify that the composition obtained in this invention can effectively reduce the probability of rainwater entering the pores of wood, radial holes were drilled in 45 eucalyptus trees with a diameter at breast height (DBH) of approximately 0.5 m in Niulingshui Forest Farm, Lianping County, Guangdong Province. The holes were 10 cm in diameter and 15 cm in length. After 45 days of natural recovery, the holes were cleaned and a wireless humidity probe was installed on the innermost side of each hole. Nine eucalyptus trees were randomly selected and grouped into five groups, namely Examples 1-3 and Comparative Examples 1-2. The holes were then filled with the composition obtained in the corresponding examples or comparative examples (filled completely, with the outer end of the filler flush with the hole opening; after filling, a baffle was used to seal the hole opening, and the baffle was removed after 8 hours). 72 hours after removing the baffle, a sprayer was used at a spray nozzle with a spray nozzle diameter of 0.25 m. 3 A continuous spray was applied to the tunnel entrance at a flow rate of / h for 8 hours. After spraying stopped, the relative humidity inside the tunnel was measured by a wireless humidity probe in each group, and the average value was taken. The results are shown in Table 2.

[0035] Table 2 shows the humidity inside the holes for each embodiment and comparative example.

[0036] Hole Group Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Average humidity (%) 67.7 68.9 67.2 67.5 91.1 Standard deviation 1.15 1.26 1.14 1.33 3.93

[0037] As shown in Table 2, the composition obtained in this invention significantly improves the water-blocking ability of pores simply because of the different types of expanding agents. This demonstrates that the Artemisia argyi adhesive can keep the interior of wood pores dry and reduce the rate of internal decay.

[0038] Fire extinguishing experiment

[0039] To verify that the composition obtained in this invention can extinguish open flames in tree cavities, a lychee tree with a diameter at breast height of approximately 0.3 m was drilled at a 45° angle, penetrating the trunk to form a cavity approximately 5 cm in diameter. The lychee trees were randomly divided into 5 groups of 19 trees each, designated as Examples 1-3 and Comparative Examples 1-2. Both ends of the cavities were sealed with plastic film. The upper end was filled with the composition corresponding to the group. After one year, the plastic film at the top of the cavity was removed, and methane was injected into the cavity through the plastic film using an air pump (one year of growth is sufficient for the cavity to expand and form a gap between it and the filling material for methane flow). Once methane was detected at the top of the cavity using a combustible gas detector, the air pump was immediately removed. Then, an ignition point was lit at the top of the cavity. After one minute, the presence of an open flame was observed. The number of cavities with open flames was counted, and the flame retardancy rate was calculated as (19 - number of cavities with open flames) / 19. The results are shown in Table 3.

[0040] Table 3. Statistics of tree holes with open flames

[0041] Tree Hole Group Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 A tree hollow containing an open flame. 1 0 0 6 3 Flame retardancy rate (%) 94.7 100 100 68.4 84.2

[0042] Comparative Example 1 does not use aluminum hydroxide, so when the tree hole catches fire, it cannot produce moisture to allow the Artemisia argyi to expand, making it difficult to push ABS particles and other substances to extinguish the fire. In contrast, Comparative Example 2 uses IFR as an expanding agent, which decomposes into gas and viscous substances to quickly extinguish the fire. Although it also has a high flame retardant rate, its working principle is different from that of this invention.

[0043] In addition, the survival of the trees was observed in this experiment, but no lychee trees withered or died, which shows that the invention is safe.

[0044] The embodiments and descriptions above are merely illustrative of the principles and preferred embodiments of the present invention. Various changes and modifications may be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A method of using a flame-retardant ABS composition, wherein the flame-retardant ABS composition is prepared from the following raw materials in parts by weight: The ingredients include 1000-1400 parts ABS granules, 350-450 parts polysiloxane, 100-200 parts dimethyl silicone oil, 300-600 parts flame retardant, 100-300 parts inorganic filler, 5-40 parts crosslinking agent, 2-20 parts coupling agent, 0.5-2 parts catalyst, and 1-2 parts expanding agent. The ABS granules are V0 grade flame-retardant ABS resin; the particle size of the ABS granules is 0.25 cm; the polysiloxane is a mixture of 2000 viscous α,ω-dihydroxypolydimethylsiloxane and 50000 viscous α,ω-dihydroxypolydimethylsiloxane in a weight ratio of 5:1; the dimethyl silicone oil is 100 viscous dimethyl silicone oil; the flame retardant is aluminum hydroxide; the inorganic filler is light calcium carbonate; the crosslinking agent is methyltrimethoxysilane; the coupling agent is KH-570; the catalyst is dibutyltin dilaurate; the expanding agent is Artemisia argyi. The method for preparing the flame-retardant ABS composition includes the following steps: Step 1: Add polysiloxane, dimethyl silicone oil, flame retardant and inorganic filler to a double planetary mixer and disperse them under vacuum heating and stirring. Step 2: After cooling to 25°C, nitrogen gas is introduced to standard atmospheric pressure. Then, an expanding agent, crosslinking agent, coupling agent, and catalyst are added to the nitrogen atmosphere and dispersed at high speed to obtain a colloid. Step 3: Add ABS particles under a nitrogen atmosphere and stir at low speed to obtain the composition; The vacuum heating and stirring dispersion parameters are: temperature 110℃, vacuum degree -0.05MPa, and rotation speed 1400rpm for 2 hours; the high-speed dispersion parameters are: rotation speed 1400rpm for 20 minutes; and the low-speed stirring parameters are: rotation speed 50-150rpm for 15-45 minutes. The characteristic feature is that the flame-retardant ABS composition is used to fill the holes in the tree to extinguish the fire source in the spontaneous combustion of the hole; the tree is a lychee tree.