Polypropylene composition, process for its preparation and use thereof

Abstract

This application discloses a polypropylene composition, its preparation method, and its applications, belonging to the field of polymer materials technology. The polypropylene composition comprises the following components in parts by weight: 100 parts polypropylene resin, 4-11 parts choline compounds, 9-22 parts silane coupling agent-modified talc, and 2.5-9 parts compatibilizer; the choline compounds include choline salt compounds. The polypropylene material of this application uses polypropylene resin as a matrix. Under the combined action of choline compounds, silane coupling agent-modified talc, and compatibilizer, a polypropylene composition with excellent coating adhesion and resistance to damp heat is obtained. This polypropylene composition is suitable for manufacturing automotive parts and household appliances, especially for manufacturing bumpers, door panels, and pillars.

Description

Technical Field

[0001] This application relates to the field of polymer materials technology, specifically to a polypropylene composition, its preparation method, and its application. Background Technology

[0002] Polypropylene resin is widely used in the automotive, home appliance and many other industries due to its advantages such as low price, excellent mechanical properties and simple molding process.

[0003] In the automotive industry, polypropylene resin materials are used in a range of interior and exterior components, including bumpers, door panels, and pillars. Exterior components, such as bumpers, often require surface coating. Because polypropylene is a non-polar material with low surface energy and relatively low adhesion to paint, common automotive polypropylene coatings typically require primer, color coat, and topcoat to meet part requirements, resulting in significant costs.

[0004] Therefore, how to improve the coating adhesion of polypropylene materials has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this application is to overcome the shortcomings of the existing technology and provide a polypropylene composition, its preparation method and application, wherein the polypropylene composition has excellent coating adhesion and resistance to damp heat.

[0006] To achieve the above objectives, the technical solution adopted in this application is as follows: A polypropylene composition comprising the following components in parts by weight: 100 parts polypropylene resin, 4-11 parts choline compounds, 9-22 parts silane coupling agent modified talc, and 2.5-9 parts compatibilizer. The choline compounds include choline salt compounds.

[0007] This invention creatively combines the above-mentioned raw materials. The polypropylene composition uses polypropylene resin as the matrix. Under the combined action of choline compounds, silane coupling agents to modify talc powder, and compatibilizers, a polypropylene composition with excellent coating adhesion and resistance to damp heat is obtained. The polypropylene composition is suitable for the preparation of automotive parts and household appliances, and is especially suitable for the preparation of bumpers, door panels, and pillars.

[0008] The choline compounds mentioned herein comprise choline salts composed of choline cations and various hydrophilic anions. During injection molding and cooling, due to the difference between the polar and non-polar PP matrix, and driven by molecular diffusion and surface energy, the choline compounds selectively migrate to the surface of the product, forming a weak layer rich in polar functional groups. This significantly increases the surface energy and allows them to form hydrogen bonds or electrostatic interactions with the polar groups in the topcoat. The silane coupling agent-modified talc can covalently bond with the paint during the paint curing process through the coupling agent, thereby achieving excellent adhesion of the primerless coating. The silane coupling agent-modified talc has good compatibility with PP and exhibits superhydrophobicity. The talc is exfoliated into a sheet-like structure within the PP matrix. The disordered stacking of talc sheets at the PP-paint interface effectively blocks the diffusion and penetration of water vapor molecules into the interface layer, significantly delaying the damage of the bonding interface by water molecules. The rigid flakes of talc can also play a certain reinforcing role and improve heat resistance. With the synergistic effect of the two, the coating adhesion and damp heat resistance of the polypropylene composition are effectively improved.

[0009] The amount of the choline compound used is 4 to 11 parts, for example, it can be 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts or any two of these values.

[0010] Preferably, the amount of the choline compound is 5 to 10 parts.

[0011] The amount of silane coupling agent modified talc is 9 to 22 parts, for example, it can be 9 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts or any two of these values.

[0012] Preferably, the amount of silane coupling agent modified talc is 10-20 parts.

[0013] The amount of the compatibilizer is 2.5 to 9 parts, for example, it can be 2.5 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or any two of these values.

[0014] Preferably, the amount of the compatibilizer is 3 to 8 parts.

[0015] Preferably, the mass ratio of the silane coupling agent modified talc to the choline salt compound is (1.2~4):1, for example, it can be 1.2:1, 1.5:1, 1.8:1, 2:1, 2.5:1, 3:1, 3.2:1, 3.5:1, 4:1 or any two of these values.

[0016] Preferably, the mass ratio of the silane coupling agent-modified talc to the choline salt compound is (1.8~3.2):1.

[0017] Preferably, the polypropylene composition comprises the following components in parts by weight: 100 parts polypropylene resin, 5-10 parts choline compounds, 10-20 parts silane coupling agent modified talc, and 3-8 parts compatibilizer.

[0018] Preferably, the choline salt compound includes at least one of choline acetate, choline mesylate (CAS: 55357-38-5), choline chloride, and choline phosphate.

[0019] Preferably, the choline compound includes at least one of choline mesylate and choline chloride, which can further improve coating adhesion and resistance to damp heat.

[0020] In the polypropylene composition of the present invention, the polypropylene resin has a weight percentage of not less than 60%.

[0021] Preferably, in the polypropylene composition of the present invention, the weight percentage of the polypropylene resin is 65-83%, for example, it can be 65%, 66%, 68%, 70%, 72%, 75%, 76%, 78%, 80%, 82%, 83%, or any two of these values.

[0022] Preferably, it also includes 0 to 1.2 parts of additives, for example, it can be 0 parts, 0.2 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.8 parts, 1 part, 1.2 parts or any two of these values.

[0023] Preferably, it includes 0 to 1 part of an adjuvant.

[0024] Preferably, the silane coupling agent modified talc powder comprises a silane coupling agent and talc powder, wherein the weight ratio of the silane coupling agent to talc powder is (0.5~4):(96~99.5), for example, it can be 0.5:99.5, 1:99, 2:98, 3:97, 4:96 or any two of these values.

[0025] Preferably, the silane coupling agent modified talc powder comprises a silane coupling agent and talc powder, wherein the weight ratio of the silane coupling agent to talc powder is (1~2):(98~99).

[0026] Preferably, the lamellar index of the talc powder is 1.5 to 6, for example, it can be 1.5, 2, 3, 4, 5, 5.6, 6, or any two of these values. By controlling the lamellar index of the talc powder within this range, the coating adhesion and resistance to damp heat can be further improved. When the lamellar index is too low, the lamellar structure of the talc powder is not obvious, and the improvement on the coating adhesion after high temperature and high humidity is limited. When the lamellar index is too high, the lamellar structure is too thin, which may lead to uneven dispersion and may also cause an increase in the melt viscosity and a decrease in fluidity of the material system during injection molding, resulting in weak coating adhesion after high temperature and high humidity.

[0027] Preferably, the talc powder has a lamellar index of 2 to 4.

[0028] The talc lamellar index is calculated as (d50 laser - d50 sedimentation) / d50 sedimentation, where d50 laser is tested according to GB / T 19077.1-particle size analysis-laser diffraction method, and d50 sedimentation is tested according to GB / T26645.1-2011-particle size analysis-liquid gravity sedimentation method.

[0029] Preferably, the silane coupling agent comprises at least one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, 3-(2,3-epoxypropoxy)propylmethyldimethoxysilane, γ-glycidoxypropyltriethoxysilane, β-(3,4-epoxycyclohexyl)-ethyltriethoxysilane, β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, 3-(2,3-epoxypropoxy)propylmethyldiethoxysilane, vinyltris(2-methoxyethoxy)silane, vinyltrimethoxysilane, and vinyltriethoxysilane.

[0030] It should be noted that the present invention can use conventional methods in the prior art to prepare silane coupling agent modified talc powder from silane coupling agent and talc powder. The present invention is not limited to the preparation method. The following is an exemplary method for preparing silane coupling agent modified talc powder.

[0031] Method 1: Place talc powder and silane coupling agent into a high-speed mixer and stir evenly at 55~65℃ (speed can be 50~400rpm, time can be 0.5~6h). Ball mill and sieve to the target particle size to obtain silane coupling agent modified talc powder.

[0032] Method 2: Disperse the silane coupling agent in an ethanol solution (concentration of 10~90wt%), add talc powder, stir evenly (heating to 50~70℃ can increase the speed), filter, dry, ball mill and sieve to the target particle size to obtain silane coupling agent modified talc powder.

[0033] Method 3: Disperse the silane coupling agent in an ethanol solution (concentration of 10~90wt%), spray the mixture evenly on the surface of talc powder, dry, ball mill and sieve to the target particle size to obtain silane coupling agent modified talc powder.

[0034] Preferably, the polypropylene resin has a melt flow rate of 6~50 g / 10 min at 230℃ / 2.16 kg according to ISO1133-2011 method, for example, it can be 6 g / 10 min, 8 g / 10 min, 10 g / 10 min, 20 g / 10 min, 30 g / 10 min, 40 g / 10 min, 50 g / 10 min or any two of these values.

[0035] Preferably, the polypropylene resin has a melt flow rate of 10~26 g / 10 min at 230°C / 2.16 kg according to ISO 1133-2011 method.

[0036] Preferably, the compatibilizer includes at least one of maleic anhydride-grafted polypropylene, glycidyl methacrylate-grafted polypropylene, and acrylic acid-grafted polypropylene. In the presence of the compatibilizer, the compatibilizer can effectively improve the compatibility between non-polar polypropylene and choline compounds and silane coupling agent-modified talc. The system formed by the three is relatively more stable and can further improve coating adhesion and resistance to damp heat.

[0037] Preferably, the adjuvant includes an antioxidant.

[0038] Preferably, the antioxidant includes at least one of thioester antioxidants, hindered phenolic antioxidants, hydroxylamine antioxidants, phosphite antioxidants, and phosphate antioxidants.

[0039] Preferably, the thioester antioxidant includes at least one of dialkyl thiodipropionate or pentaerythritol tetra(3-lauryl thiopropionate).

[0040] Preferably, the hindered phenolic antioxidant comprises at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate, octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, vinylbis(oxyvinyl)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate] or 3,9-bis[1,1-dimethyl-2-[(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane.

[0041] Preferably, the hydroxylamine antioxidant includes bis(octadecyl)hydroxylamine.

[0042] Preferably, the phosphite antioxidant includes at least one of tris(2,4-di-tert-butylphenyl) phosphite, pentaerythritol bis(2,4-tert-butylphenyl) phosphite, and bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate.

[0043] Preferably, the polypropylene composition of the present invention may further include at least one of a stabilizer, a lubricant, a mineral powder, an antistatic agent, and a flame retardant.

[0044] Preferably, the stabilizer includes at least one of hindered amine light stabilizers, triazine light stabilizers, benzotriazole light stabilizers, and benzophenone light stabilizers.

[0045] The polypropylene composition of the present invention may include a lubricant, and suitable lubricants include at least one selected from hyperbranched polyester, stearate, ethylene bis-stearamide, and polyethylene wax.

[0046] The polypropylene composition of the present invention may include mineral powder, and suitable mineral powders include, but are not limited to, calcium carbonate, mica, kaolin, magnesium hydroxide, borax, and combinations thereof.

[0047] The polypropylene composition of the present invention may include an antistatic agent, and suitable antistatic agents include, but are not limited to, zinc oxide, manganese dioxide, chromium trioxide, and combinations thereof.

[0048] The polypropylene compositions of the present invention may include flame retardants, suitable flame retardants including but not limited to brominated polymers (e.g., brominated polystyrene), metal dialkyl phosphites (e.g., tris(diethylphosphite)aluminum), metal hydroxides (e.g., magnesium hydroxide), aromatic phosphates (e.g., resorcinol di(diphenyl phosphate) and bisphenol A di(diphenyl phosphate) and combinations thereof).

[0049] This application also provides a method for preparing a polypropylene composition, comprising the following steps: According to the formula, the choline compound and compatibilizer are mixed evenly, and then mixed evenly with the remaining components. The mixture is then melt-extruded and granulated to obtain a polypropylene composition.

[0050] This application also provides an application of a polypropylene composition in the preparation of automotive parts or household appliances.

[0051] This application also provides a product prepared using the polypropylene composition described above, the product including automotive parts or household appliances.

[0052] The beneficial effects of this application are as follows: The polypropylene material described in this application uses polypropylene resin as the matrix, and under the combined action of choline compounds, silane coupling agents to modify talc powder, and compatibilizers, a polypropylene composition with excellent coating adhesion and resistance to damp heat is obtained. The polypropylene composition is suitable for the preparation of automotive parts and household appliances, and is especially suitable for the preparation of bumpers, door panels, and pillars. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0054] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0055] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0056] The raw materials used in the examples and comparative examples are described below: PP-1: The melt flow rate was 26 g / 10 min at 230℃ / 2.16 kg. It was purchased from Sinopec and its grade was PPH-Y26.

[0057] PP-2: The melt flow rate was 10 g / 10 min at 230℃ / 2.16 kg. It was purchased from CNOOC Shell, grade PPHP500N.

[0058] PP-3: Melt flow rate of 50 g / 10 min at 230℃ / 2.16 kg weight, purchased from Sinopec (Tianjin), grade PP EP5075X.

[0059] PP-4: Melt flow rate of 6 g / 10 min at 230℃ and 2.16 kg, purchased from LyondellBasell, grade PP Moplen RP215MX B.

[0060] Choline acetate: Commercially available.

[0061] Choline chloride: Commercially available.

[0062] Choline mesylate: Commercially available.

[0063] Phosphocholine: Commercially available.

[0064] Silane coupling agent modified talc-1: consists of γ-aminopropyltriethoxysilane and talc in a mass ratio of 2:98. The talc has a lamellar index of 4 and was purchased from Imerys under the brand name HART84.

[0065] Silane coupling agent modified talc-2: consists of γ-aminopropyltriethoxysilane and talc in a mass ratio of 1:99. The talc has a lamellar index of 4 and was purchased from Imerys under the brand name HART84.

[0066] Silane coupling agent modified talc-3: consists of γ-aminopropyltriethoxysilane and talc in a mass ratio of 0.5:99.5. The talc has a lamellar index of 4 and was purchased from Imerys under the brand name HART84.

[0067] Silane coupling agent modified talc-4: consists of γ-aminopropyltriethoxysilane and talc in a mass ratio of 4:96. The talc has a lamellar index of 4 and was purchased from Imerys under the brand name HART84.

[0068] Silane coupling agent modified talc-5: consists of γ-aminopropyltriethoxysilane and talc in a mass ratio of 2:98. The talc has a lamellar index of 2 and was purchased from Imerys under the brand name HART77.

[0069] Silane coupling agent modified talc-6: consists of γ-aminopropyltriethoxysilane and talc in a mass ratio of 2:98. The talc has a lamellar index of 5.6 and was purchased from Suzhou Youkuang Plastics, with the grade T-4.

[0070] Silane coupling agent modified talc-7: consists of γ-aminopropyltriethoxysilane and talc in a mass ratio of 2:98. The talc has a lamellar index of 1.5 and was purchased from Longsheng Huamei Talc Development Co., Ltd., with the grade AH-1250N6.

[0071] Silane coupling agent modified talc-8: consists of γ-glycidyl etheroxypropyltrimethoxysilane and talc in a mass ratio of 2:98. The talc has a lamellar index of 4 and was purchased from Imerys under the brand name HART84.

[0072] The preparation methods of silane coupling agent modified talc powder-1~7 all include the following steps: talc powder and γ-aminopropyltriethoxysilane are placed in a high-speed mixer (the mass ratio of the two is (96~99.5):(0.5~4)), and stirred evenly at 60℃ (the speed is 200 rpm, and the time can be 4h) to obtain silane coupling agent modified talc powder-1~7.

[0073] The preparation method of silane coupling agent modified talc-8 includes the following steps: dispersing γ-glycidoxypropyltrimethoxysilane in an ethanol solution (concentration of 50wt%), adding talc powder, stirring evenly at 60℃, filtering, drying, ball milling and sieving to the target particle size to obtain silane coupling agent modified talc-8.

[0074] In the preparation method of silane coupling agent modified talc powder-1~7, the ratio of talc powder to γ-aminopropyltriethoxysilane in the silane coupling agent modified talc powder can be changed by controlling the ratio of talc powder to γ-aminopropyltriethoxysilane, and the lamellar index can be changed by adjusting the grade of talc powder.

[0075] PP-g-GMA: Glycidyl methacrylate grafted polypropylene, Guangzhou Dongjin Plastics Technology Co., Ltd., grade PPG-2321.

[0076] PP-g-MAH: Maleic anhydride-grafted polypropylene, purchased from Jia Yi Rong Company, grade CMG-5701.

[0077] Talc (used in Comparative Example 6): The lamellar index was 4. The talc was purchased from Imerys and the grade was HART84.

[0078] Wollastonite: Purchased from Fengjiashan Silicon Fiber, grade WFC5-2101.

[0079] 1-Butyl-3-methylimidazolium hexafluorophosphate: Commercially available. Antioxidant: Antioxidant 1010, commercially available.

[0080] Unless otherwise specified, all components and raw materials used in the embodiments and comparative examples of this application are commercially available, and the same type of components and raw materials are used in each parallel experiment.

[0081] Examples 1-20, Comparative Examples 1-7 The formulations of the polypropylene compositions of Examples 1-20 and Comparative Examples 1-7 are shown in Tables 1 and 2 (all figures are parts by weight).

[0082] The preparation methods of the polypropylene compositions in Examples 1-20 and Comparative Examples 1-7 all include the following steps: According to the formula, the choline compound and compatibilizer are mixed evenly, and then mixed evenly with the remaining components. The mixture is fed into a twin-screw extruder (length-to-diameter ratio of 40:1) for melt mixing. The processing temperatures (from the feed port to the die) are 180℃, 180℃, 180℃, 200℃, 200℃, 200℃, 200℃, 200℃, and the screw speed is 500 rpm. The mixture is then extruded and granulated to obtain a polypropylene composition.

[0083] Table 1 Table 2 Performance testing 1. Coating Adhesion (Peel Strength): The polypropylene composition prepared above was injection molded into a 100*100*2mm square plate sample. The square plate sample was then sprayed with the following process: water washing and degreasing → water blowing → drying → cooling → spraying color paint (water-based paint) → static leveling → baking at 80℃ for 5 min → spraying clear varnish (water-based paint, PP1070, Guangzhou Haoyi New Materials) → static leveling → baking at 80℃ for 30 min → cooling. The drying temperature was 60℃ and the drying time was 30 min. The film thickness of the polypropylene composite material after spraying was 0.1mm. The coating adhesion after spraying was tested, and the tensile strength of the coating peeling from the material surface was measured. The final test result was the average of three measurements, and the peel strength unit was N / m. The test tensile speed was 50mm / min, the peel width was 10mm, the peel angle was 180°, and the test temperature was 23℃. The results are shown in Table 3.

[0084] 2. Coating adhesion after high temperature and high humidity: After the above-sprayed polypropylene composite material was placed in an environment of 85% humidity and 85℃ for 30 days, the coating adhesion was tested again, and the results are shown in Table 3.

[0085] Table 3 As can be seen from Table 3, the polypropylene composition described in this application has excellent coating adhesion and resistance to damp heat. The polypropylene composition is suitable for manufacturing automotive parts and household appliances, especially for manufacturing bumpers, door panels, and pillars. The peel strength of the polypropylene composition is ≥1325 N / m, and the peel strength after high temperature and high humidity is ≥1110 N / m.

[0086] As can be seen from Table 3, the choline compounds and silane coupling agent modified talc powder described in this application have a synergistic effect in improving the coating adhesion and damp heat resistance of the polypropylene composition. The absence of any one of them or the use of other components will lead to a significant decrease in coating adhesion and damp heat resistance.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit the scope of protection of this application. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the substance and scope of the technical solutions of this application.

Claims

1. A polypropylene composition, characterized in that, It includes the following components in parts by weight: 100 parts polypropylene resin, 4-11 parts choline compounds, 9-22 parts silane coupling agent modified talc, and 2.5-9 parts compatibilizer; The choline compounds include choline salt compounds.

2. The polypropylene composition according to claim 1, characterized in that, The mass ratio of the silane coupling agent-modified talc to the choline salt compound is (1.2~4):

1.

3. The polypropylene composition according to claim 1, characterized in that, The silane coupling agent modified talc powder comprises a silane coupling agent and talc powder, wherein the weight ratio of the silane coupling agent to talc powder is (0.5~4):(96~99.5); and / or The talc powder has a lamellar index of 1.5 to 6.

4. The polypropylene composition according to claim 1, characterized in that, The choline salt compound includes at least one of acetic choline, mesylate choline, choline chloride, and phosphate choline.

5. The polypropylene composition according to claim 3, characterized in that, The silane coupling agent includes at least one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, 3-(2,3-epoxypropoxy)propylmethyldimethoxysilane, γ-glycidoxypropyltriethoxysilane, β-(3,4-epoxycyclohexyl)-ethyltriethoxysilane, β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, 3-(2,3-epoxypropoxy)propylmethyldiethoxysilane, vinyltris(2-methoxyethoxy)silane, vinyltrimethoxysilane, and vinyltriethoxysilane.

6. The polypropylene composition according to claim 1, characterized in that, The melt flow rate of the polypropylene resin at 230℃ / 2.16kg is 6~50g / 10min; and / or The compatibilizer includes at least one of maleic anhydride-grafted polypropylene, glycidyl methacrylate-grafted polypropylene, and acrylic acid-grafted polypropylene.

7. The polypropylene composition according to claim 1, characterized in that, It also includes 0 to 1.2 parts of additives.

8. A method for preparing the polypropylene composition according to any one of claims 1 to 7, characterized in that, Includes the following steps: According to the formula, the choline compound and compatibilizer are mixed evenly, and then mixed evenly with the remaining components. The mixture is then melt-extruded and granulated to obtain a polypropylene composition.

9. The use of the polypropylene composition according to any one of claims 1 to 7 in the preparation of automotive parts or household appliances.

10. A product characterized in that, The product is prepared using the polypropylene composition according to any one of claims 1 to 7, and the product includes automotive parts or household appliances.

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