Environment-friendly PVC fireproof heat-insulation bottom coating for automobiles and preparation method of environment-friendly PVC fireproof heat-insulation bottom coating

Abstract

The invention relates to the technical field of fireproof coatings, in particular to an environment-friendly PVC fireproof heat-insulation bottom coating for an automobile and a preparation method of the environment-friendly PVC fireproof heat-insulation bottom coating. The environment-friendly PVC fireproof heat-insulation bottom coating for the automobile is prepared from the following components in percentage by mass: 10 to 16 percent of diisononyl phthalate, 8 to 15 percent of phosphate, 2.5 to 6 percent of solvent, 1 to 3 percent of polyamide, 0.5 to 2 percent of zinc oxide stabilizer, 3 to 7 percent of calcium oxide, 0.1 to 1 percent of gas silicon, 0.1 to 0.5 percent of additive, 20 to 30 percent of PVC resin, 7 to 15 percent of inorganic silicate and the balance of filler, the sum of the mass percentages of all the components is 100%. The fireproof and flame-retardant performance of the environment-friendly PVC fireproof and heat-insulating bottom coating for the automobile can reach the V0 level, meanwhile, the environment-friendly PVC fireproof and heat-insulating bottom coating for the automobile has good heat-insulating performance and storage stability, and the problems that an existing PVC fireproof and heat-insulating bottom coating for the automobile is poor in fireproof and flame-retardant performance when the content of a flame retardant is insufficient; and if a large amount of flame retardant is added, the storage stability becomes poor.

Description

Technical Field

[0001] The invention relates to the technical field of fireproof coatings, and in particular to an environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles and a preparation method thereof. Background Art

[0002] In the manufacturing process of the new energy vehicle industry, the safety of the battery module is crucial to the safety of new energy vehicles. When a battery pack module fails, in order to protect the safety of the occupants in the vehicle to the greatest extent, the battery pack at the bottom of the vehicle body needs to be treated with fire retardant treatment. The current fire retardant treatment method is generally to apply fire retardant paint to the bottom of the car. In the event of a fire, the spread of the fire can be prevented or delayed, so as to leave sufficient escape time for the occupants in the vehicle.

[0003] Most automotive underbody coatings use high-strength polyvinyl chloride resin (PVC) as the main material, and are composed of plasticizers, tackifiers, fillers and other materials. In the traditional formula, diisononyl phthalate or epoxy soybean oil is used as a plasticizer, and calcium carbonate is used as a filler. However, the prepared automotive PVC underbody coating has relatively poor fire retardant properties. In the prior art, the flame retardant properties are usually improved by adding a certain amount of flame retardant. However, when the content of the flame retardant is insufficient, the fire retardant properties of the automotive PVC underbody coating are poor, and a large amount of flame retardant added will cause the storage stability of the automotive PVC underbody coating to deteriorate. Summary of the invention

[0004] In response to the problems raised by the background technology, the first purpose of the present invention is to propose an environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles. By combining diisononyl phthalate, phosphate ester and inorganic silicate, the fireproof and flame retardant properties of the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles are effectively improved while ensuring its storage stability, thereby solving the problem that the existing PVC fireproof and heat-insulating bottom coating for automobiles has poor fireproof and flame retardant properties when the flame retardant content is insufficient, while the addition of a large amount of flame retardant will lead to poor storage stability.

[0005] The second purpose of the present invention is to propose a preparation method for the above-mentioned environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles. The prepared environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles has fire retardant performance that meets the V0 level and has good storage stability. It solves the problem that the existing PVC fireproof and heat-insulating bottom coating for automobiles has poor fire retardant performance when the flame retardant content is insufficient, and the addition of a large amount of flame retardant will lead to poor storage stability.

[0006] To achieve the above purpose, the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles proposed by the present invention comprises the following components in percentage by mass: 10-16% of diisononyl phthalate, 8-15% of phosphate ester, 2.5-6% of solvent, 1-3% of polyamide, 0.5-2% of zinc oxide stabilizer, 3-7% of calcium oxide, 0.1-1% of gas silicate, 0.1-0.5% of auxiliary agent, 20-30% of PVC resin, 7-15% of inorganic silicate and the remainder of filler, and the total percentage content of each component by mass is 100%.

[0007] Optionally, the filler is selected from one or a combination of nano calcium carbonate, heavy calcium carbonate, ammonium polyphosphate, phosphorus-nitrogen complex, aluminum hydroxide, kaolin, diatomaceous earth, ceramic powder, and zirconium oxide.

[0008] Optionally, the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles further comprises the following components in percentage by mass: 2-5% of a microsphere foaming agent and 0.1-0.5% of a pigment.

[0009] Optionally, the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles includes the following components in mass percentage: 10-16% diisononyl phthalate, 8-15% phosphate, 2.5-6% solvent, 1-3% polyamide, 0.5-2% zinc oxide stabilizer, 3-7% calcium oxide, 0.1-1% gas silicate, 0.1-0.5% additive, 20-30% PVC resin, 7-15% inorganic silicate, 8-18% nano calcium carbonate, 10-14% aluminum hydroxide, 1-6% zirconium oxide, 2-6% ceramic powder, 2-5% microsphere foaming agent and 0.1-0.5% pigment.

[0010] Optionally, the inorganic silicate is calcium silicate, the solvent is a saturated alkane, and the auxiliary agent is diethylene glycol.

[0011] Optionally, the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles includes the following components in mass percentage: 13% diisononyl phthalate, 12% phosphate ester, 8% calcium silicate, 12% aluminum hydroxide, 2% zirconium oxide, 4% ceramic powder, 2% microsphere foaming agent, 2.5-6% saturated alkane, 1-3% polyamide, 0.5-2% zinc oxide stabilizer, 3-7% calcium oxide, 0.1-1% gas silica, 0.1-0.5% diethylene glycol, 8-18% nano calcium carbonate, 20-30% PVC resin and 0.1-0.5% pigment.

[0012] The present invention also provides a method for preparing an environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles, which is used to prepare the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles, comprising the following steps:

[0013] Step S1, preparing raw materials according to the component dosage of environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles, adding diisononyl phthalate and phosphate ester into a reaction kettle, and stirring for 3-5 minutes;

[0014] Step S2, while maintaining stirring, adding solvent, polyamide, zinc oxide stabilizer, calcium oxide, gas silicon, additives, filler and inorganic silicate into the reaction kettle, and continuing stirring for 30 minutes;

[0015] Step S3, adding PVC resin into the reactor while maintaining stirring, continuing stirring for 5-10 minutes, and controlling the temperature of the material in the reactor to be between 20° C. and 30° C. to obtain a mixed product;

[0016] Step S4, placing the mixed product obtained in step S3 at rest for 16 hours to obtain the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles.

[0017] Optionally, in step S2, a microsphere foaming agent and a pigment are added into the reaction kettle while maintaining stirring.

[0018] Optionally, the method for preparing the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles further comprises step S5:

[0019] Step S5, vacuuming and filtering the environmentally friendly automotive PVC fireproof and heat-insulating bottom coating obtained in step S4 to obtain a finished product.

[0020] Optionally, in step S1, the stirring speed is 35 to 45 rpm.

[0021] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0022] 1. The present invention uses diisononyl phthalate, phosphate ester and inorganic silicate in combination, so that both phosphate ester and inorganic silicate have good fire retardant properties. At the same time, inorganic silicate can play a filling and supporting role in the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles, and can prevent phosphate molecules from colliding and adhering to each other during storage, slow down the oxidation reaction rate of phosphate ester, avoid the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles due to excessively high phosphate content. Skinning or agglomeration phenomenon, effectively improving the storage stability of the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles.

[0023] 2. The filler of the present invention is preferably a combination of nano calcium carbonate, aluminum hydroxide, ceramic powder and zirconium oxide. Among them, the process of aluminum hydroxide being thermally decomposed at high temperature can absorb a large amount of heat, and the water vapor produced can also dilute the concentration of combustible gas and oxygen. The produced aluminum oxide protective film can isolate oxygen and catalyze the thermal cross-linking reaction of the polymer to form a dense carbon layer, which can play a role in both fire retardancy and heat insulation; the main components of the ceramic powder are silicon dioxide and aluminum oxide, which can catalyze the formation of the carbon layer, strengthen the carbon layer, and effectively isolate flames and heat; zirconium oxide undergoes a phase change at high temperature, from a monoclinic phase to a tetragonal phase, which can absorb heat and improve the thermal insulation performance of the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles.

[0024] 3. The present invention uses a combination of phosphate ester, inorganic silicate, aluminum hydroxide, zirconium oxide, ceramic powder and microsphere foaming agent, so that the fire retardant performance of the environmentally friendly automotive PVC fireproof and heat-insulating bottom coating meets the V0 level and has good storage stability and heat-insulating performance; at the same time, the content of aluminum hydroxide can be reduced by adding a microsphere foaming agent, while ensuring the heat-insulating performance, avoiding the problem of loss of adhesion of the environmentally friendly automotive PVC fireproof and heat-insulating bottom coating in the double 85 aging test due to the large amount of aluminum hydroxide used. DETAILED DESCRIPTION

[0025] In order to facilitate the understanding of the present invention, the present invention is described more fully below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0026] If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the field or the product instructions are used. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0027] The invention provides an environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles, which comprises the following components in percentage by mass: 10-16% of diisononyl phthalate, 8-15% of phosphate, 2.5-6% of solvent, 1-3% of polyamide, 0.5-2% of zinc oxide stabilizer, 3-7% of calcium oxide, 0.1-1% of gas silicon, 0.1-0.5% of auxiliary agent, 20-30% of PVC resin, 7-15% of inorganic silicate and the remainder of filler, wherein the total percentage of the components by mass is 100%.

[0028] The environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles of the present invention is used to coat the bottom of the automobile to form a coating, thereby playing a role in fire prevention and flame retardancy. By using the diisononyl phthalate, the phosphate ester and the inorganic silicate in combination, the fire retardant performance of the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles can be improved, so that its fireproof level can meet the V0 level in the vertical method of GB / T2408-2021, and at the same time, the storage stability of the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles can be ensured, solving the problem that the existing PVC fireproof and heat-insulating bottom coating for automobiles has poor fireproof and flame retardant performance when the flame retardant content is insufficient, and the addition of a large amount of flame retardant will lead to poor storage stability.

[0029] During combustion, the phosphate ester decomposes to form a non-flammable liquid film of phosphoric acid, which covers the surface of the base material such as the bottom of the car to play a covering effect, thereby isolating oxygen. The phosphoric acid further reacts to form polymetaphosphoric acid, which is a strong dehydrating agent and can dehydrate and carbonize the polymer to form a carbon layer, thereby further isolating oxygen and heat. The moisture generated by the phosphate ester during the decomposition process can both reduce the temperature of the condensed phase and dilute the concentration of combustibles in the gas phase. At the same time, the phosphate ester can also act as a free radical scavenger during combustion, combining with hydrogen atoms in the flame to suppress the flame. During the research process, the inventors found that when the phosphate ester is used alone, in order to ensure that the fire retardant properties of the environmentally friendly automotive PVC fire-retardant and heat-insulating bottom coating can meet the V0 level in the GB / T2408-2021 vertical method, the amount of the phosphate ester needs to be increased; however, when the content of the phosphate ester is too high, when the environmentally friendly automotive PVC fire-retardant and heat-insulating bottom coating is exposed to the air, a skinning phenomenon will appear on its surface in a short period of time (3 days), and long-term exposure to the air will further cause agglomeration, which will seriously damage the storage stability of the environmentally friendly automotive PVC fire-retardant and heat-insulating bottom coating and affect the processing and use performance.

[0030] The present invention uses the phosphate ester and the inorganic silicate in combination. When the inorganic silicate is burned, it can decompose to produce silicon dioxide, thereby forming an isolation film to isolate oxygen and play a fire-retardant role. At the same time, it can catalyze the formation of carbonized products and strengthen the carbon layer, creating a good physical barrier. It can reduce the content of the phosphate ester while ensuring that the fire-retardant performance of the environmentally friendly automotive PVC fire-proof and heat-insulating bottom coating meets the V0 level; at the same time, the inorganic silicate can also play a filling and supporting role in the environmentally friendly automotive PVC fire-proof and heat-insulating bottom coating, which can prevent the phosphate ester molecules from colliding and adhering to each other during storage, slow down the oxidation reaction rate of the phosphate ester, avoid the skin or agglomeration phenomenon of the environmentally friendly automotive PVC fire-proof and heat-insulating bottom coating caused by the excessively high content of the phosphate ester, and effectively improve the storage stability of the environmentally friendly automotive PVC fire-proof and heat-insulating bottom coating.

[0031] To further illustrate, the filler is selected from one or a combination of nano calcium carbonate, heavy calcium carbonate, ammonium polyphosphate, phosphorus-nitrogen complex, aluminum hydroxide, kaolin, diatomaceous earth, ceramic powder, and zirconium oxide.

[0032] By adding the filler, the performance of the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles can be improved. For example, the nano calcium carbonate can improve the strength and toughness of the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles; the heavy calcium carbonate can increase the volume of the product and reduce the cost; the ammonium polyphosphate and the phosphorus-nitrogen complex are flame retardants and can improve the flame retardant performance; the aluminum hydroxide, the ceramic powder, and the zirconium oxide are good heat insulating agents and can improve the heat insulating performance.

[0033] Preferably, the filler is selected from a combination of the nano calcium carbonate, the aluminum hydroxide, the ceramic powder and the zirconium oxide.

[0034] The process of thermal decomposition of the aluminum hydroxide at high temperature can absorb a large amount of heat, and the generated water vapor can also dilute the concentration of combustible gas and oxygen. The generated aluminum oxide protective film can isolate oxygen and catalyze the thermal cross-linking reaction of the polymer to form a dense carbon layer, which can not only play a fire retardant role but also a heat insulating role; the main components of the ceramic powder are silicon dioxide and aluminum oxide, which can catalyze the formation of the carbon layer, strengthen the carbon layer, and effectively isolate flames and heat; the zirconium oxide undergoes a phase change at high temperature, from a monoclinic phase to a tetragonal phase, which can absorb heat and improve the thermal insulation performance of the environmentally friendly automotive PVC fireproof and heat-insulating bottom coating.

[0035] To further illustrate, the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles also includes the following components in percentage by mass: 2-5% of microsphere foaming agent and 0.1-0.5% of pigment.

[0036] The microsphere foaming agent will foam and expand when heated, and has the characteristic of high-efficiency foaming. After the microsphere foaming agent foams and expands, a gas cavity can be formed between the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles, thereby achieving a good heat-insulating effect.

[0037] Further description, the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles includes the following components in mass percentage: 10-16% of diisononyl phthalate, 8-15% of phosphate ester, 2.5-6% of solvent, 1-3% of polyamide, 0.5-2% of zinc oxide stabilizer, 3-7% of calcium oxide, 0.1-1% of gas silicate, 0.1-0.5% of additive, 20-30% of PVC resin, 7-15% of inorganic silicate, 8-18% of nano calcium carbonate, 10-14% of aluminum hydroxide, 1-6% of zirconium oxide, 2-6% of ceramic powder, 2-5% of microsphere foaming agent and 0.1-0.5% of pigment.

[0038] The filler comprises a combination of the following components: a combination of the nano calcium carbonate, the aluminum hydroxide, the ceramic powder and the zirconium oxide; and a microsphere foaming agent is also added;

[0039] The present invention uses the phosphate ester, the inorganic silicate, the aluminum hydroxide, the zirconium oxide, the ceramic powder and the microsphere foaming agent in combination, so that the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles can improve the heat insulation performance under the premise that the fireproof grade meets the V0 level in the vertical method of GB / T 2408-2021. Specifically, the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles is applied to an electrophoresis plate, and the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles is burned at 1200° C. for 30 minutes. The temperature of the back plate of the electrophoresis plate is always lower than 300° C., and the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles has good heat insulation performance.

[0040] To further illustrate, the inorganic silicate is calcium silicate, the solvent is a saturated alkane, and the auxiliary agent is diethylene glycol.

[0041] The inorganic silicate has good flame retardant and heat-insulating properties. When calcium silicate burns, it can decompose to produce silicon dioxide, thereby forming an isolation film to isolate oxygen, play a role in fire retardancy, and at the same time can catalyze the formation of carbonized products, and strengthen the carbon layer, creating a good physical barrier, which can reduce the content of the phosphate ester while ensuring that the environmentally friendly automotive PVC fire-retardant and heat-insulating bottom coating fire retardant performance meets the V0 level in the vertical method of GB / T 2408-2021; at the same time, the calcium silicate can also play a filling and supporting role, which can prevent the phosphate molecules from colliding and bonding with each other during storage, slow down the rate of the oxidation reaction of the phosphate ester, avoid the crusting or agglomeration caused by the excessively high content of the phosphate ester, and effectively improve the storage stability of the environmentally friendly automotive PVC fire-retardant and heat-insulating bottom coating. Furthermore, the inorganic silicate can also be magnesium silicate, which has similar properties to the calcium silicate and comparable flame retardant and heat-insulating properties.

[0042] The solvent is a saturated alkane, which has a stable molecular structure and is not easily oxidized or reduced. The volatile organic compound (VOC) content of the saturated alkane is lower than that of the unsaturated alkane, and the pollution to the environment is relatively small. At the same time, by adjusting the proportion of the saturated alkane, the viscosity and fluidity of the environmentally friendly automotive PVC fireproof and heat-insulating bottom coating can be controlled to adapt to different coating processes and requirements, and facilitate construction and spraying. Specifically, the saturated alkane can be selected from one of the common saturated alkanes such as n-decane, n-tridecane or n-tetradecane.

[0043] The auxiliary agent is diethylene glycol. By using the diethylene glycol as an auxiliary agent, the coating performance and film-forming performance of the environmentally friendly automotive PVC fire-proof and heat-insulating bottom coating can be improved, making the coating smoother and flatter. The diethylene glycol and the gas silicon work synergistically to adjust and control the thixotropy and viscosity of the environmentally friendly automotive PVC fire-proof and heat-insulating bottom coating to adapt to different coating processes and requirements and facilitate construction and spraying.

[0044] Further description, the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles includes the following components in percentage by mass: 13% diisononyl phthalate, 12% phosphate, 8% calcium silicate, 12% aluminum hydroxide, 2% zirconium oxide, 4% ceramic powder, 2% microsphere foaming agent, 2.5-6% saturated alkane, 1-3% polyamide, 0.5-2% zinc oxide stabilizer, 3-7% calcium oxide, 0.1-1% gas silica, 0.1-0.5% diethylene glycol, 8-18% nano calcium carbonate, 20-30% PVC resin and 0.1-0.5% pigment.

[0045] The environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles is used in combination with the diisononyl phthalate, the phosphate ester and the calcium silicate, the content of the phosphate ester is 12%, and the content of the calcium silicate is 8%. The prepared environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles has a fireproof grade that meets the V0 grade and has good storage stability;

[0046] By using the phosphate ester, the calcium silicate, the aluminum hydroxide, the zirconium oxide, the ceramic powder and the microsphere foaming agent in combination, the thermal insulation performance of the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles can be improved; specifically, the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles is coated on an electrophoresis plate, and the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles is burned at 1200° C. for 30 minutes, and the temperature of the back plate of the electrophoresis plate is always lower than 300° C., indicating that the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles has good thermal insulation performance.

[0047] Since the large amount of aluminum hydroxide used may easily cause the environmentally friendly automotive PVC fireproof and heat-insulating bottom coating to suffer from adhesion loss in the double 85 aging test (aging for 2000 hours in an environment with a temperature and humidity of 85°C and 85% RH, respectively), (the large amount of aluminum hydroxide used may increase the strength of the environmentally friendly automotive PVC fireproof and heat-insulating bottom coating, and increase the stress during the aging process, thereby causing the coating to deform or warp, separate from the substrate, and cause adhesion loss); by setting the content of aluminum hydroxide to 12%, zirconium oxide to 2%, ceramic powder to 4%, and microsphere foaming agent to 2%, that is, reducing the content of aluminum hydroxide while adding the microsphere foaming agent, the problem of adhesion loss of the environmentally friendly automotive PVC fireproof and heat-insulating bottom coating in the double 85 aging test due to the large amount of aluminum hydroxide used can be avoided while ensuring the thermal insulation performance.

[0048] The present invention also provides a method for preparing an environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles, which is used to prepare the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles, comprising the following steps:

[0049] Step S1, preparing raw materials according to the component dosage of environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles, adding diisononyl phthalate and phosphate ester into a reaction kettle, and stirring for 3-5 minutes;

[0050] Step S2, while maintaining stirring, adding solvent, polyamide, zinc oxide stabilizer, calcium oxide, gas silicon, additives, filler and inorganic silicate into the reaction kettle, and continuing stirring for 30 minutes;

[0051] Step S3, adding PVC resin into the reactor while maintaining stirring, continuing stirring for 5-10 minutes, and controlling the temperature of the material in the reactor to be between 20° C. and 30° C. to obtain a mixed product;

[0052] Step S4, placing the mixed product obtained in step S3 at rest for 16 hours to obtain the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles.

[0053] By adopting the diisononyl phthalate and the phosphate ester as plasticizers and adding the inorganic silicate at the same time, the fire retardant performance can be ensured while reducing the phosphate ester content, and the fire resistance level meets the V0 level. At the same time, the storage stability of the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles can be ensured, thereby solving the problem that the existing PVC fireproof and heat-insulating bottom coating for automobiles has poor fire retardant performance when the flame retardant content is insufficient, and the addition of a large amount of flame retardant will lead to poor storage stability.

[0054] To further explain, in the step S2, a microsphere foaming agent and a pigment are added into the reaction kettle while maintaining stirring.

[0055] The environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles is prepared by combining the diisononyl phthalate, the phosphate ester, the inorganic silicate, the aluminum hydroxide, the zirconium oxide, the ceramic powder and the microsphere foaming agent. The fireproof level of the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles meets the V0 level and has good heat insulation performance, storage stability and adhesion performance.

[0056] Further, the method for preparing the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles further comprises step S5:

[0057] Step S5, vacuuming and filtering the environmentally friendly automotive PVC fireproof and heat-insulating bottom coating obtained in step S4 to obtain a finished product.

[0058] The environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles is subjected to a vacuum treatment before packaging, which can eliminate bubbles, make the coating formed by the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles during the painting process more uniform, and improve the overall quality and aesthetics of the coating; the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles is also subjected to a filtering treatment before packaging, which can remove impurities (such as iron filings, oil, welding slag and other impurities), ensure the purity of the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles, and avoid adverse effects such as particles or uneven surface of the coating during painting.

[0059] Further, between step S4 and step S5, the following steps are also included: adjusting the viscosity of the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles obtained in step S4 according to actual use needs, and the specific steps are: testing the initial viscosity of the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles, and adding one or more combinations of diisononyl phthalate, solvents or fillers to adjust the viscosity of the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles to within the target range according to the initial viscosity.

[0060] To further illustrate, in step S1, the stirring speed is 35 to 45 rpm.

[0061] Add the diisononyl phthalate and the phosphate ester into the reactor and stir for 3-5 minutes, preferably at a stirring speed of 40 rpm, to ensure that the various components of the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles can be fully mixed and uniformly avoided, and problems such as stratification, uneven color or rough texture can be avoided. Further, the stirring speed in step S2, step S3 and step S4 is 35-45 rpm, and the preferred stirring speed is 40 rpm.

[0062] Further, in step S3, a cooling device is used to control the temperature of the material in the reactor. The cooling device is a water chiller, which can quickly cool and control the temperature of the material in the reactor to be below 30°C.

[0063] (I) Example 1 and Comparative Examples 1 to 4:

[0064] (1) Embodiment 1:

[0065] The environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles comprises the following components in percentage by mass: 16% of diisononyl phthalate, 12% of phosphate, 5.5% of solvent (n-decane), 1.5% of polyamide, 0.5% of zinc oxide stabilizer, 5% of calcium oxide, 0.7% of gas silicon, 0.3% of auxiliary agent (diethylene glycol), 12% of inorganic silicate (calcium silicate), filler (12% of nano calcium carbonate, 13% of heavy calcium carbonate), and 21.5% of PVC resin.

[0066] The preparation method of Example 1 is:

[0067] Step S1, preparing raw materials according to the component dosage of environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles, adding diisononyl phthalate and phosphate ester into a reaction kettle, and stirring for 3-5 minutes;

[0068] Step S2, while maintaining stirring, sequentially add solvent (n-decane), polyamide, zinc oxide stabilizer, calcium oxide, gas silicon, auxiliary agent (diethylene glycol), filler (nano calcium carbonate and heavy calcium carbonate) and inorganic silicate (calcium silicate) into the reactor, and continue stirring for 30 minutes;

[0069] Step S3, adding PVC resin into the reactor while maintaining stirring, continuing stirring for 5-10 minutes, and controlling the temperature of the material in the reactor to be less than 30 degrees Celsius to obtain a mixed product;

[0070] Step S4, placing the mixed product obtained in step S3 at rest for 16 hours to obtain the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles.

[0071] (2) Comparative Examples 1 to 4:

[0072] The difference between Comparative Examples 1 to 4 and Example 1 is that the components and contents of the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles are different. The specific components and contents are as shown in Table 1 (where "-" indicates that the component is not added):

[0073] (3) Performance testing and result analysis:

[0074] The environmentally friendly automotive PVC fireproof and heat-insulating bottom coatings prepared in Example 1 and Comparative Examples 1 to 4 were subjected to flame retardant performance tests and storage stability tests:

[0075] The flame retardant performance test method and judgment method are carried out in accordance with the following standards: the vertical method in GB / T 2408-2021 "Horizontal and vertical methods for determination of combustion performance of plastics", wherein the flame retardant performance of the environmentally friendly automotive PVC fire retardant and heat-insulating bottom coating reaches the V0 level and is judged to be qualified, and the flame retardant performance is below the V0 level and is judged to be unqualified.

[0076] The test method for storage stability is: ① Short-term storage stability: At 25°C, expose the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles to the air for 3 days, and observe whether there is any skinning or agglomeration on its surface; ② Long-term storage stability: At 25°C, seal and store the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles for 3 months, and observe whether there is any skinning or agglomeration on its surface. Judgment criteria: The environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles does not show any skinning or agglomeration in both the short-term storage stability and long-term storage stability tests, and is judged to be qualified; the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles shows any skinning or agglomeration in either the short-term storage stability or long-term storage stability tests, and is judged to be unqualified. The test results are shown in Table 2:

[0077] Table 1 Components and contents of Example 1 and Comparative Examples 1 to 4 (unit: in mass percentage)

[0078]

[0079] Table 2 Test results of Example 1 and Comparative Examples 1 to 4

[0080]

[0081] It can be seen from the data in Table 1 and Table 2 that the combination of the phosphate ester and the inorganic silicate in Example 1 can make the fire retardant performance of the environmentally friendly PVC fire-proof and heat-insulating bottom coating for automobiles meet the V0 level, while also ensuring that the storage stability of the environmentally friendly PVC fire-proof and heat-insulating bottom coating for automobiles is qualified.

[0082] Comparative Examples 1 to 3 did not add the inorganic silicate. Although the storage stability of the prepared environmentally friendly automotive PVC fireproof and heat-insulating bottom coating was qualified, its flame retardant performance could not reach the V0 level. Comparative Example 4 also did not add the inorganic silicate, but increased the content of the phosphate ester so that its flame retardant performance could reach the V0 level, but the result of its storage stability test was unqualified.

[0083] When phosphate ester is used alone as a flame retardant, a higher content of the phosphate ester is required to ensure that the flame retardant performance of the environmentally friendly automotive PVC fire-proof and heat-insulating bottom coating can meet the V0 level. However, due to the high content of the phosphate ester, the short-term storage stability and long-term storage stability of the environmentally friendly automotive PVC fire-proof and heat-insulating bottom coating are unqualified.

[0084] By using the phosphate ester and the inorganic silicate in combination, the inorganic silicate can decompose to produce silicon dioxide when burned, thereby forming an isolation film to isolate oxygen and play a fire-retardant role. At the same time, it can catalyze the formation of carbonized products and strengthen the carbon layer, creating a good physical barrier, which can reduce the content of the phosphate ester while ensuring that the environmentally friendly automotive PVC fire-retardant and heat-insulating bottom coating has a V0 level of fire-retardant performance; at the same time, the inorganic silicate can play a filling and supporting role in the environmentally friendly automotive PVC fire-retardant and heat-insulating bottom coating, which can prevent the phosphate ester molecules from colliding and bonding with each other during storage, slow down the oxidation reaction rate of the phosphate ester, avoid skinning or agglomeration caused by excessively high phosphate ester content, and effectively improve the storage stability of the environmentally friendly automotive PVC fire-retardant and heat-insulating bottom coating.

[0085] (II) Examples 2 to 3 and Comparative Examples 5 to 8:

[0086] (1) Embodiments 2 to 3:

[0087] The difference between Examples 2 to 3 and Comparative Examples 5 to 8 and Example 1 is that the components and contents of the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles are different, and the specific components and contents are as shown in Table 3 (wherein "-" indicates that the component is not added);

[0088] The preparation methods of Examples 2 to 3 are:

[0089] Step S1, preparing raw materials according to the component dosage of environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles, adding diisononyl phthalate and phosphate ester into a reaction kettle, and stirring for 3-5 minutes;

[0090] Step S2, while maintaining stirring, sequentially adding solvent (saturated alkane), polyamide, zinc oxide stabilizer, calcium oxide, gas silicon, additive (diethylene glycol), filler (nano calcium carbonate, aluminum hydroxide, zirconium oxide and ceramic powder) and inorganic silicate (calcium silicate) into the reactor, and continuing stirring for 30 minutes after adding;

[0091] Step S3, adding PVC resin into the reactor while maintaining stirring, continuing stirring for 5-10 minutes, and controlling the temperature of the material in the reactor to be less than 30 degrees Celsius to obtain a mixed product;

[0092] Step S4, placing the mixed product obtained in step S3 at rest for 16 hours to obtain the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles.

[0093] (2) Comparative Examples 5 to 8:

[0094] The difference between Comparative Examples 5 to 8 and Example 2 is that the components and contents of the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles are different. The specific components and contents are as shown in Table 3 (where "-" indicates that the component is not added):

[0095] (3) Performance testing and result analysis:

[0096] The environmentally friendly automotive PVC fireproof and heat-insulating bottom coatings prepared in Examples 2 to 3 and Comparative Examples 5 to 8 were subjected to flame retardant performance tests, storage stability tests and heat-insulating performance tests. The test results are shown in Table 4: (wherein, the flame retardant performance test and the storage stability test are the same as the test method and judgment method in the above-mentioned Example 1).

[0097] Thermal insulation performance test: The environmentally friendly automotive PVC fireproof and heat-insulating bottom coating prepared in Examples 2 to 3 and Comparative Examples 5 to 8 is applied to an electrophoretic plate, and the environmentally friendly automotive PVC fireproof and heat-insulating bottom coating is burned with a high-temperature flame of 1200°C for 30 minutes, and the maximum temperature of the back plate of the electrophoretic plate is tested and recorded.

[0098] Table 3 Components and contents of Examples 2 to 3 and Comparative Examples 5 to 8 (unit: in mass percentage)

[0099]

[0100] Table 4 Test results of Examples 2 to 3 and Comparative Examples 5 to 8

[0101]

[0102] The process of thermal decomposition of the aluminum hydroxide at high temperature can absorb a large amount of heat, and the generated water vapor can also dilute the concentration of combustible gas and oxygen. The generated aluminum oxide protective film can isolate oxygen and catalyze the thermal cross-linking reaction of the polymer to form a dense carbon layer, which can not only play a fire retardant role but also a heat insulating role; the main components of the ceramic powder are silicon dioxide and aluminum oxide, which can catalyze the formation of the carbon layer, strengthen the carbon layer, and effectively isolate flames and heat; the zirconium oxide undergoes a phase change at high temperature, from a monoclinic phase to a tetragonal phase, which can absorb heat and improve the thermal insulation performance of the environmentally friendly automotive PVC fireproof and heat-insulating bottom coating.

[0103] It can be seen from the data in Table 3 and Table 4 that in Example 2 and Example 3, the phosphate ester, the inorganic silicate, the aluminum hydroxide, the zirconium oxide and the ceramic powder are used in combination, so that the environmentally friendly automotive PVC fireproof and heat-insulating bottom coating can ensure that the flame retardant performance meets the V0 level and the storage stability test result is qualified. At the same time, when the environmentally friendly automotive PVC fireproof and heat-insulating bottom coating is burned at 1200°C for 30 minutes, the temperature of the back plate of the electrophoretic plate is lower than 300°C, indicating that the environmentally friendly automotive PVC fireproof and heat-insulating bottom coating has good thermal insulation performance.

[0104] Comparative Examples 5 to 8 use different combinations of filler types from Example 2. The flame retardancy can meet the V0 level and the storage stability test results are qualified, but the thermal insulation test results are all greater than 300°C, and the thermal insulation performance is worse than that of Examples 2 and 3.

[0105] (II) Examples 4 to 6 and Comparative Examples 9 to 10:

[0106] (1) Embodiments 4 to 6:

[0107] The difference between Examples 4 to 6 and Comparative Example 9 and Example 1 is that the components and contents of the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles are different, and the specific components and contents are as shown in Table 5;

[0108] The preparation methods of Examples 4 to 6 are:

[0109] Step S1, preparing raw materials according to the component dosage of environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles, adding diisononyl phthalate and phosphate ester into a reaction kettle, and stirring for 3-5 minutes;

[0110] Step S2, while maintaining stirring, sequentially adding solvent (saturated alkane), polyamide, zinc oxide stabilizer, calcium oxide, gas silicon, additive (diethylene glycol), filler (nano calcium carbonate, aluminum hydroxide, zirconium oxide and ceramic powder), inorganic silicate (calcium silicate), microsphere foaming agent and pigment into the reactor, and continuing stirring for 30 minutes after adding;

[0111] Step S3, adding PVC resin into the reactor while maintaining stirring, continuing stirring for 5-10 minutes, and controlling the temperature of the material in the reactor to be less than 30 degrees Celsius to obtain a mixed product;

[0112] Step S4, placing the mixed product obtained in step S3 at rest for 16 hours to obtain the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles.

[0113] (2) Comparative Examples 9 to 10:

[0114] The difference between Comparative Examples 9 and 10 and Example 4 is that the components and contents of the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles are different. The specific components and contents are as shown in Table 5 (where "-" indicates that the component is not added):

[0115] (3) Performance testing and result analysis:

[0116] The environmentally friendly automotive PVC fireproof and heat-insulating bottom coatings prepared in Examples 4 to 6 and Comparative Examples 9 to 10 were subjected to flame retardant performance tests, storage stability tests, heat-insulating performance tests and adhesion tests, and the test results are shown in Table 4: (wherein, the flame retardant performance test and the storage stability test are the same as the test method and determination method in the above-mentioned Example 1, and the heat-insulating performance test is the same as the test method and determination method in the above-mentioned Examples 2 to 3).

[0117] Adhesion test: The environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles prepared in Examples 4 to 6 and Comparative Examples 9 to 10 is applied to a sample plate substrate to form a coating on the sample plate substrate, and aged for 2000 hours in an environment with a temperature of 85°C and a humidity of 85% RH (such as a test box that can accurately control temperature and humidity), and the adhesion of the coating is checked for loss. Specifically, adhesion loss means that the coating warps, partially or completely detaches from the sample plate substrate; good adhesion means that a 1 cm strip is drawn on the coating and torn by hand, and the strip does not peel off from the sample plate substrate and is completely cohesively broken.

[0118] The environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles was burned with a high-temperature flame of 1200° C. for 30 minutes, and the maximum temperature of the back plate of the electrophoresis plate was tested and recorded.

[0119] Table 5 Components and contents of Examples 4 to 6 and Comparative Examples 9 to 10 (unit: in mass percentage)

[0120]

[0121] Table 6 Test results of Examples 4 to 6 and Comparative Examples 9 to 10

[0122]

[0123] The microsphere foaming agent will foam and expand when heated, and has the characteristic of high-efficiency foaming. After the microsphere foaming agent foams and expands, a gas cavity can be formed between the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles, thereby achieving a good heat-insulating effect.

[0124] It can be seen from the data in Table 5 and Table 6 that the flame retardant properties of the environmentally friendly automotive PVC fireproof and heat-insulating bottom coatings of Comparative Examples 9 to 10 can meet the V0 level, the storage stability test results are qualified, and the results of the thermal insulation performance test can also reach below 300°C. However, due to the high content of aluminum hydroxide, the strength of the environmentally friendly automotive PVC fireproof and heat-insulating bottom coating is increased, and the stress is enhanced during the aging process, which causes the coating to deform or warp, separate from the substrate, and cause adhesion loss.

[0125] In Examples 4 to 6, the content of the aluminum hydroxide is reduced, and the phosphate ester, the inorganic silicate, the aluminum hydroxide, the zirconium oxide, the ceramic powder and the microsphere foaming agent are used in combination, so that the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles can ensure that the flame retardant performance meets the V0 level, and the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles is burned at 1200°C for 30 minutes. The temperature of the back plate of the electrophoresis plate is always lower than 300°C, and the storage stability test and adhesion test results are both qualified, indicating that the prepared environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles has good flame retardant properties, heat insulation properties, storage stability and good adhesion.

[0126] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles, characterized in that: The invention comprises the following components in percentage by mass: 10-16% of diisononyl phthalate, 8-15% of phosphate, 2.5-6% of solvent, 1-3% of polyamide, 0.5-2% of zinc oxide stabilizer, 3-7% of calcium oxide, 0.1-1% of gas silicon, 0.1-0.5% of auxiliary agent, 20-30% of PVC resin, 7-15% of inorganic silicate and the remainder of filler, and the total percentage by mass of each component is 100%.

2. The environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles according to claim 1, characterized in that: The filler is selected from one or a combination of nano calcium carbonate, heavy calcium carbonate, ammonium polyphosphate, phosphorus-nitrogen complex, aluminum hydroxide, kaolin, diatomaceous earth, ceramic powder, and zirconium oxide.

3. The environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles according to claim 2, characterized in that: The environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles further comprises the following components in percentage by mass: 2-5% of a microsphere foaming agent and 0.1-0.5% of a pigment.

4. The environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles according to claim 3, characterized in that: The environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles comprises the following components in percentage by mass: 10-16% of diisononyl phthalate, 8-15% of phosphate, 2.5-6% of solvent, 1-3% of polyamide, 0.5-2% of zinc oxide stabilizer, 3-7% of calcium oxide, 0.1-1% of gas silicate, 0.1-0.5% of auxiliary agent, 20-30% of PVC resin, 7-15% of inorganic silicate, 8-18% of nano calcium carbonate, 10-14% of aluminum hydroxide, 1-6% of zirconium oxide, 2-6% of ceramic powder, 2-5% of microsphere foaming agent and 0.1-0.5% of pigment.

5. The environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles according to claim 4, characterized in that: The inorganic silicate is calcium silicate, the solvent is saturated alkane, and the auxiliary agent is diethylene glycol.

6. The environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles according to claim 5, characterized in that: The environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles comprises the following components in percentage by mass: 13% of diisononyl phthalate, 12% of phosphate, 8% of calcium silicate, 12% of aluminum hydroxide, 2% of zirconium oxide, 4% of ceramic powder, 2% of microsphere foaming agent, 2.5-6% of saturated alkane, 1-3% of polyamide, 0.5-2% of zinc oxide stabilizer, 3-7% of calcium oxide, 0.1-1% of gas silicon, 0.1-0.5% of diethylene glycol, 8-18% of nano calcium carbonate, 20-30% of PVC resin and 0.1-0.5% of pigment.

7. A method for preparing an environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles, which is used to prepare the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: Step S1, preparing raw materials according to the component dosage of environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles, adding diisononyl phthalate and phosphate ester into a reaction kettle, and stirring for 3-5 minutes; Step S2, while maintaining stirring, adding solvent, polyamide, zinc oxide stabilizer, calcium oxide, gas silicon, additives, filler and inorganic silicate into the reaction kettle, and continuing stirring for 30 minutes; Step S3, adding PVC resin into the reactor while maintaining stirring, continuing stirring for 5-10 minutes, and controlling the temperature of the material in the reactor to be between 20° C. and 30° C. to obtain a mixed product; Step S4, placing the mixed product obtained in step S3 at rest for 16 hours to obtain the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles.

8. The method for preparing the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles according to claim 7, characterized in that: In the step S2, a microsphere foaming agent and a pigment are added into the reaction kettle while maintaining stirring.

9. The method for preparing the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles according to claim 8, characterized in that: The method for preparing the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles further comprises step S5: Step S5, vacuuming and filtering the environmentally friendly automotive PVC fireproof and heat-insulating bottom coating obtained in step S4 to obtain a finished product.

10. The method for preparing the environmentally friendly PVC fireproof and heat-insulating bottom coating for automobiles according to claim 8, characterized in that: In the step S1, the stirring speed is 35 to 45 rpm.

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