Biodegradable bath ball and preparation method thereof

Abstract

This invention relates to the field of bath product technology and provides a biodegradable bath ball and its preparation method. The biodegradable bath ball comprises the following raw materials: polylactic acid, EVA, polyhydroxybutyrate, chitosan, sericin, modified starch, and a mixture of modified polyethylene glycol. The biodegradable bath ball provided by this invention incorporates biodegradable materials such as polylactic acid, EVA, polyhydroxybutyrate, chitosan, sericin, modified starch, and modified polyethylene glycol, making the bath ball more environmentally friendly and biodegradable. The addition of chitosan provides multiple physiological functions such as biodegradability, biocompatibility, non-toxicity, and antibacterial properties, giving the bath ball antibacterial function. The addition of modified starch and modified polyethylene glycol allows for synergistic effects, resulting in a large molecular network structure formed through the interaction of the materials, further improving the mechanical properties of the bath ball.

Description

Technical Field

[0001] This invention belongs to the field of bath product technology, and particularly relates to a biodegradable bath ball and its preparation method. Background Technology

[0002] Biodegradable polymers are polymers that can be completely degraded after being eroded by organisms in nature, such as bacteria, fungi, and algae.

[0003] Bath balls, also known as bath sponges or bath flowers, are used in saunas or baths. You put shower gel on a bath ball to create foam, then gently rub it on your skin to produce a lot of foam. There are many varieties available.

[0004] Conventional bath sponges are made of PE material, which is difficult to degrade in 100-200 years and is extremely harmful to the environment. Bath sponges have a short lifespan and are replaced quickly, but they are difficult to degrade, thus creating a large amount of plastic waste, which is detrimental to environmental protection. Summary of the Invention

[0005] This invention provides a biodegradable bath sponge and its preparation method, aiming to solve the above-mentioned problems.

[0006] This invention is achieved as follows: a biodegradable bath ball comprising the following raw materials in parts by weight: 50-70 parts polylactic acid, 20-40 parts EVA, 10-20 parts polyhydroxybutyrate, 4-8 parts chitosan, 3-7 parts sericin, and 30-40 parts a mixture of modified starch and modified polyethylene glycol. The EVA has a relative density of 0.93-0.94 and a gloss of 82-85.

[0007] Preferably, the raw materials include the following in parts by weight: 55-65 parts polylactic acid, 25-35 parts EVA, 12-18 parts polyhydroxybutyrate, 5-7 parts chitosan, 4-6 parts sericin, and 32-38 parts a mixture of modified starch and modified polyethylene glycol.

[0008] Preferably, the raw materials comprise the following in parts by weight: 60 parts polylactic acid, 30 parts EVA, 15 parts polyhydroxybutyrate, 6 parts chitosan, 5 parts sericin, and 35 parts a mixture of modified starch and modified polyethylene glycol.

[0009] Preferably, the modified starch is prepared as follows: 8-12 parts by weight of starch extracted from renewable plants (such as corn), 1-3 parts by weight of methacrylic acid, 1-2 parts by weight of hydrogen peroxide, and 1-2 parts by weight of sodium stearate are weighed and set aside; the methacrylic acid and sodium stearate are emulsified under ultrasonic conditions for 30-40 minutes to obtain an emulsion; the starch raw material is preheated at 60-80°C for 30-40 minutes under ultrasonic conditions and nitrogen protection at room temperature, and the temperature is maintained at 60-80°C while hydrogen peroxide is added and reacted for 10-20 minutes to obtain a reactant; the emulsion is added to the reactant, and the mixture is stirred at a speed of 1200-1800 r / min to carry out a chemical reaction. The modified starch is obtained in 20-30 minutes. The modified starch not only has biodegradable properties, but also significantly enhances the grafting reaction effect by emulsifying methacrylic acid in the presence of ultrasound and then grafting it with starch. This greatly improves the grafting rate and efficiency. At the same time, the energy generated by ultrasound breaks the hydrogen bonds within and between starch molecules, disrupting the order of starch molecules. This allows the modified monomers to move more easily within the starch granules and graft with the active functional groups in the starch molecules. As a result, the modified starch has a three-dimensional network microstructure with interconnected pores, which can fully combine with other materials, improving material stability and mechanical properties.

[0010] Preferably, the modified polyethylene glycol is prepared as follows: Under stirring, 1-2 parts by weight of polyethylene glycol are added dropwise to 5-6 parts by weight of sulfonium bromide. During the dropwise addition, the system temperature is maintained at 2-4°C, then the temperature is raised to 50-60°C, and then added dropwise to 12-14 parts by weight of anhydrous diethyl ether. The mixture is filtered, washed, and dried. The product is dissolved in 7-10 parts by weight of N,N-dimethylformamide, and 0.5-1 parts by weight of 3-amino-1,2-propanediol and 0.6-1.2 parts by weight of diethylamine are added. The mixture is heated to 80-90°C and stirred for 3-5 hours. The mixture is extracted with dichloromethane, precipitated with anhydrous diethyl ether, and dried under vacuum to obtain modified polyethylene glycol. By treating polyethylene glycol and grafting amino groups onto the ends of polyethylene glycol, the reactivity of polyethylene glycol can be effectively enhanced, allowing for more complete compounding with other materials. The reaction between them forms a macromolecular network structure, which enhances the mechanical properties of the bath ball.

[0011] A method for preparing a biodegradable bath sponge includes the following steps:

[0012] 1) Weigh each raw material according to the proportions;

[0013] 2) Mix polylactic acid, EVA, polyhydroxybutyrate, chitosan, sericin, modified starch and modified polyethylene glycol, and stir at 1500-2000 r / min for 1-2 h until uniformly mixed to obtain a mixed material;

[0014] 3) The mixed material is heated and melted at a temperature of 200-220℃, then molded and cooled to obtain a mesh-shaped semi-finished product. The heating and melting are carried out in a mesh stretching machine.

[0015] 4) The mesh-type semi-finished product is stretched after being pulled, drained, pulled again, and wound up.

[0016] 5) Cut and garnish the stretched semi-finished product to obtain a bath ball.

[0017] Preferably, in step 2), after every 10-20 minutes of stirring, the mixture is irradiated with ultraviolet light for 20-30 seconds while stirring, wherein the ultraviolet light wavelength is 200-400 nm and the power density is 1000-2000 mW / cm². 2 By treating with ultraviolet light, a three-dimensional network cross-linked structure is generated between the raw materials and between the molecular structures within each raw material, which can significantly improve the mechanical properties of the material.

[0018] Preferably, the ultraviolet irradiation treatment uses an ultraviolet irradiation crosslinking device with a specific light source, such as a thermionic-excited medium-pressure mercury arc lamp or a microwave-excited electrodeless lamp with added gallium (V-shaped lamp).

[0019] Compared with the prior art, the embodiments of this application have the following main advantages:

[0020] The biodegradable bath sponge provided by this invention incorporates a mixture of polylactic acid, EVA, polyhydroxybutyrate, chitosan, sericin, modified starch, and modified polyethylene glycol, resulting in excellent degradation performance and a more environmentally friendly product. The addition of chitosan provides multiple physiological functions, including biodegradability, biocompatibility, non-toxicity, and antibacterial properties, giving the bath sponge high antibacterial ability and a long-lasting antibacterial effect, making it healthier and safer. Furthermore, the addition of the modified starch and modified polyethylene glycol mixture not only gives the modified starch biodegradability but also porous structure. The interconnected three-dimensional network microstructure allows for thorough integration with other materials. Modified polyethylene glycol exhibits high reactivity, enabling it to be more readily combined with other materials. The interaction between these materials forms a macromolecular network structure, allowing modified starch and modified polyethylene glycol to work synergistically. This interaction significantly improves the mechanical properties of the bath ball. During the preparation of the bath ball, ultraviolet irradiation is applied during the mixing of the components to create a three-dimensional network cross-linked structure between the raw materials and within their molecular structures, further enhancing the material's mechanical properties. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating the preparation process of a biodegradable bath ball provided by the present invention. Detailed Implementation

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0023] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0024] Example 1

[0025] This invention provides a biodegradable bath sponge, such as... Figure 1 As shown, 50 parts of polylactic acid, 20 parts of EVA, 10 parts of polyhydroxybutyrate, 4 parts of chitosan, 3 parts of sericin, and 30 parts of a mixture of modified starch and modified polyethylene glycol were weighed according to the specified ratio. One part by weight equals 5g. The EVA has a relative density of 0.93 and a gloss level of 82. The raw materials were stirred at 1500 r / min for 1 hour until homogeneous, resulting in a mixed material. The mixed material was then heated and melted at 200℃, extruded through a mold, and cooled to obtain a mesh-like semi-finished product. The melting process was carried out in a mesh stretching machine. The mesh-like semi-finished product was then stretched, drained, stretched a second time, and wound to obtain a stretched semi-finished product. The stretched semi-finished product was then cut and shaped to obtain a bath ball.

[0026] In this embodiment, the modified starch is prepared as follows: 8 parts by weight of starch extracted from renewable plants (such as corn), 1 part of methacrylic acid, 1 part of hydrogen peroxide, and 1 part of sodium stearate are weighed and set aside; the methacrylic acid and sodium stearate are emulsified under ultrasonic conditions for 30 minutes to obtain an emulsion; the starch raw material is preheated at 60°C for 30 minutes under ultrasonic conditions and nitrogen protection at room temperature, the temperature is maintained at 60°C and hydrogen peroxide is added and reacted for 10 minutes to obtain a reactant; the emulsion is added to the reactant and the mixture is stirred at 1200 r / min for 20 minutes to obtain the modified starch.

[0027] The modified polyethylene glycol is prepared as follows: Under stirring, 1 part by weight of polyethylene glycol is added dropwise to 5 parts by weight of sulfonium bromide. During the dropwise addition, the system temperature is maintained at 2°C. The temperature is then raised to 50°C and added dropwise to 12 parts by weight of anhydrous diethyl ether. The mixture is filtered through a 400-mesh filter, washed three times with water, and dried at 70°C for 30 minutes. The product is dissolved in 7 parts by weight of N,N-dimethylformamide, and 0.5 parts by weight of 3-amino-1,2-propanediol and 0.6 parts by weight of diethylamine are added. The mixture is heated to 80°C and stirred for 3 hours. The mixture is extracted with dichloromethane, precipitated with anhydrous diethyl ether, and dried under vacuum to obtain the modified polyethylene glycol.

[0028] Example 2

[0029] This invention provides a biodegradable bath sponge, such as... Figure 1 As shown, 55 parts of polylactic acid, 25 parts of EVA, 12 parts of polyhydroxybutyrate, 5 parts of chitosan, 4 parts of sericin, and 32 parts of a mixture of modified starch and modified polyethylene glycol were weighed according to the specified ratio. One part by weight equals 5g. The EVA has a relative density of 0.93 and a gloss level of 82. The raw materials were stirred at 1500 r / min for 1 hour until homogeneous, resulting in a mixed material. The mixed material was then heated and melted at 200℃, extruded through a mold, and cooled to obtain a mesh-like semi-finished product. The melting process was carried out in a mesh stretching machine. The mesh-like semi-finished product was then stretched, drained, stretched a second time, and wound to obtain a stretched semi-finished product. The stretched semi-finished product was then cut and shaped to obtain a bath ball.

[0030] In this embodiment, the modified starch is prepared as follows: 8 parts by weight of starch extracted from renewable plants (such as corn), 1 part of methacrylic acid, 1 part of hydrogen peroxide, and 1 part of sodium stearate are weighed and set aside; the methacrylic acid and sodium stearate are emulsified under ultrasonic conditions for 30 minutes to obtain an emulsion; the starch raw material is preheated at 60°C for 30 minutes under ultrasonic conditions and nitrogen protection at room temperature, the temperature is maintained at 60°C and hydrogen peroxide is added and reacted for 10 minutes to obtain a reactant; the emulsion is added to the reactant and the mixture is stirred at 1200 r / min for 20 minutes to obtain the modified starch.

[0031] The modified polyethylene glycol is prepared as follows: Under stirring, 1 part by weight of polyethylene glycol is added dropwise to 5 parts by weight of sulfonium bromide. During the dropwise addition, the system temperature is maintained at 2°C. The temperature is then raised to 50°C and added dropwise to 12 parts by weight of anhydrous diethyl ether. The mixture is filtered through a 400-mesh filter, washed three times with water, and dried at 70°C for 30 minutes. The product is dissolved in 7 parts by weight of N,N-dimethylformamide, and 0.5 parts by weight of 3-amino-1,2-propanediol and 0.6 parts by weight of diethylamine are added. The mixture is heated to 80°C and stirred for 3 hours. The mixture is extracted with dichloromethane, precipitated with anhydrous diethyl ether, and dried under vacuum to obtain the modified polyethylene glycol.

[0032] Example 3

[0033] This invention provides a biodegradable bath sponge, such as... Figure 1 As shown, 60 parts of polylactic acid, 30 parts of EVA, 15 parts of polyhydroxybutyrate, 6 parts of chitosan, 5 parts of sericin, and 35 parts of a mixture of modified starch and modified polyethylene glycol were weighed according to the specified ratio. One part by weight equals 5g. The EVA has a relative density of 0.93 and a gloss level of 83. The raw materials were stirred at 1800 r / min for 1.5 hours until homogeneous, resulting in a mixed material. The mixed material was then heated and melted at 210℃, extruded through a mold, and cooled to obtain a mesh-like semi-finished product. The melting process was carried out in a mesh stretching machine. The mesh-like semi-finished product was then stretched, drained, stretched a second time, and wound up to obtain a stretched semi-finished product. The stretched semi-finished product was then cut and shaped to obtain a bath ball.

[0034] In this embodiment, the modified starch is prepared as follows: 10 parts by weight of starch extracted from renewable plants (such as corn), 2 parts by weight of methacrylic acid, 1.5 parts by weight of hydrogen peroxide, and 1.5 parts by weight of sodium stearate are weighed and set aside. The methacrylic acid and sodium stearate are emulsified under ultrasonic conditions for 35 minutes to obtain an emulsion. The starch raw material is preheated at 70°C for 35 minutes under ultrasonic conditions and nitrogen protection at room temperature. The temperature is maintained at 70°C and hydrogen peroxide is added to react for 15 minutes to obtain a reactant. The emulsion is added to the reactant and the mixture is stirred at 1500 r / min to carry out a chemical reaction for 25 minutes to obtain the modified starch.

[0035] The modified polyethylene glycol is prepared as follows: Under stirring, 1.5 parts by weight of polyethylene glycol are added dropwise to 5.5 parts by weight of sulfonium bromide. During the dropwise addition, the system temperature is maintained at 3°C. The temperature is then raised to 55°C, and then added dropwise to 13 parts by weight of anhydrous diethyl ether. The mixture is filtered through a 400-mesh filter, washed three times with water, and dried at 70°C for 30 minutes. The product is dissolved in 8 parts by weight of N,N-dimethylformamide, and 0.7 parts by weight of 3-amino-1,2-propanediol and 0.9 parts by weight of diethylamine are added. The mixture is heated to 85°C and stirred for 4 hours. The mixture is extracted with dichloromethane, precipitated with anhydrous diethyl ether, and dried under vacuum to obtain the modified polyethylene glycol.

[0036] Example 4

[0037] This invention provides a biodegradable bath sponge, such as... Figure 1As shown, 65 parts of polylactic acid, 35 parts of EVA, 18 parts of polyhydroxybutyrate, 7 parts of chitosan, 6 parts of sericin, and 38 parts of a mixture of modified starch and modified polyethylene glycol were weighed according to the specified ratio. One part by weight equals 5g. The EVA has a relative density of 0.94 and a gloss level of 85. The raw materials were stirred at 2000 r / min for 2 hours until homogeneous, resulting in a mixed material. The mixed material was then heated and melted at 220℃, extruded through a mold, and cooled to obtain a mesh-like semi-finished product. The melting process was carried out in a mesh stretching machine. The mesh-like semi-finished product was then stretched, drained, stretched a second time, and wound to obtain a stretched semi-finished product. The stretched semi-finished product was then cut and shaped to obtain a bath ball.

[0038] In this embodiment, the modified starch is prepared as follows: 12 parts by weight of starch extracted from renewable plants (such as corn), 3 parts by weight of methacrylic acid, 2 parts by weight of hydrogen peroxide, and 2 parts by weight of sodium stearate are weighed and set aside; the methacrylic acid and sodium stearate are emulsified under ultrasonic conditions for 40 minutes to obtain an emulsion; the starch raw material is preheated at 80°C for 40 minutes under ultrasonic conditions and nitrogen protection at room temperature, and the temperature is maintained at 80°C while adding hydrogen peroxide for 20 minutes to obtain a reactant; the emulsion is added to the reactant, and the mixture is stirred at 1800 r / min for 30 minutes to obtain the modified starch.

[0039] The modified polyethylene glycol is prepared as follows: Under stirring, 2 parts by weight of polyethylene glycol are added dropwise to 6 parts by weight of sulfonium bromide. During the dropwise addition, the system temperature is maintained at 4°C. The temperature is then raised to 60°C and added dropwise to 14 parts by weight of anhydrous diethyl ether. The mixture is filtered through a 400-mesh filter, washed three times with water, and dried at 70°C for 30 minutes. The product is dissolved in 10 parts by weight of N,N-dimethylformamide, and 1 part by weight of 3-amino-1,2-propanediol and 1.2 parts by weight of diethylamine are added. The mixture is heated to 90°C and stirred for 5 hours. The mixture is extracted with dichloromethane, precipitated with anhydrous diethyl ether, and dried under vacuum to obtain the modified polyethylene glycol.

[0040] Example 5

[0041] This invention provides a biodegradable bath sponge, such as... Figure 1As shown, 70 parts of polylactic acid, 40 parts of EVA, 20 parts of polyhydroxybutyrate, 8 parts of chitosan, 7 parts of sericin, and 40 parts of a mixture of modified starch and modified polyethylene glycol were weighed according to the specified ratio. One part by weight equals 5g. The EVA has a relative density of 0.94 and a gloss level of 85. The raw materials were stirred at 2000 r / min for 2 hours until homogeneous, resulting in a mixed material. The mixed material was then heated and melted at 220℃, extruded through a mold, and cooled to obtain a mesh-like semi-finished product. The melting process was carried out in a mesh stretching machine. The mesh-like semi-finished product was then stretched, drained, stretched a second time, and wound up to obtain a stretched semi-finished product. The stretched semi-finished product was then cut and shaped to obtain a bath ball.

[0042] In this embodiment, the modified starch is prepared as follows: 12 parts by weight of starch extracted from renewable plants (such as corn), 3 parts by weight of methacrylic acid, 2 parts by weight of hydrogen peroxide, and 2 parts by weight of sodium stearate are weighed and set aside; the methacrylic acid and sodium stearate are emulsified under ultrasonic conditions for 40 minutes to obtain an emulsion; the starch raw material is preheated at 80°C for 40 minutes under ultrasonic conditions and nitrogen protection at room temperature, and the temperature is maintained at 80°C while adding hydrogen peroxide for 20 minutes to obtain a reactant; the emulsion is added to the reactant, and the mixture is stirred at 1800 r / min for 30 minutes to obtain the modified starch.

[0043] The modified polyethylene glycol is prepared as follows: Under stirring, 2 parts by weight of polyethylene glycol are added dropwise to 6 parts by weight of sulfonium bromide. During the dropwise addition, the system temperature is maintained at 4°C. The temperature is then raised to 60°C and added dropwise to 14 parts by weight of anhydrous diethyl ether. The mixture is filtered through a 400-mesh filter, washed three times with water, and dried at 70°C for 30 minutes. The product is dissolved in 10 parts by weight of N,N-dimethylformamide, and 1 part by weight of 3-amino-1,2-propanediol and 1.2 parts by weight of diethylamine are added. The mixture is heated to 90°C and stirred for 5 hours. The mixture is extracted with dichloromethane, precipitated with anhydrous diethyl ether, and dried under vacuum to obtain the modified polyethylene glycol.

[0044] Example 6 (compared to Example 3, ultraviolet irradiation treatment was added)

[0045] This invention provides a biodegradable bath sponge, such as... Figure 1 As shown, 60 parts of polylactic acid, 30 parts of EVA, 15 parts of polyhydroxybutyrate, 6 parts of chitosan, 5 parts of sericin, and 10 parts of a mixture of modified starch and modified polyethylene glycol were weighed according to the specified ratio. One part by weight equals 5g. The EVA had a relative density of 0.93 and a gloss level of 83. All raw materials were stirred at 1800 rpm for 1.5 hours until homogeneous. After every 15 minutes of stirring, the mixture was irradiated with ultraviolet light for 25 seconds while stirring. The ultraviolet light wavelength was 300 nm and the power density was 1500 mW / cm².2 The mixed material is obtained; the mixed material is heated and melted at 210°C, molded, and cooled to obtain a mesh-shaped semi-finished product, which is then heated and melted in a mesh stretching machine; the mesh-shaped semi-finished product is then stretched, drained, stretched a second time, and wound up to obtain a stretched semi-finished product; the stretched semi-finished product is then cut and shaped to obtain a bath ball;

[0046] In this embodiment, the modified starch is prepared as follows: 10 parts by weight of starch extracted from renewable plants (such as corn), 2 parts by weight of methacrylic acid, 1.5 parts by weight of hydrogen peroxide, and 1.5 parts by weight of sodium stearate are weighed and set aside. The methacrylic acid and sodium stearate are emulsified under ultrasonic conditions for 35 minutes to obtain an emulsion. The starch raw material is preheated at 70°C for 35 minutes under ultrasonic conditions and nitrogen protection at room temperature. The temperature is maintained at 70°C and hydrogen peroxide is added to react for 15 minutes to obtain a reactant. The emulsion is added to the reactant and the mixture is stirred at 1500 r / min to carry out a chemical reaction for 25 minutes to obtain the modified starch.

[0047] The modified polyethylene glycol is prepared as follows: Under stirring, 1.5 parts by weight of polyethylene glycol are added dropwise to 5.5 parts by weight of sulfonium bromide. During the dropwise addition, the system temperature is maintained at 3°C. The temperature is then raised to 55°C, and then added dropwise to 13 parts by weight of anhydrous diethyl ether. The mixture is filtered through a 400-mesh filter, washed three times with water, and dried at 70°C for 30 minutes. The product is dissolved in 8 parts by weight of N,N-dimethylformamide, and 0.7 parts by weight of 3-amino-1,2-propanediol and 0.9 parts by weight of diethylamine are added. The mixture is heated to 85°C and stirred for 4 hours. The mixture is extracted with dichloromethane, precipitated with anhydrous diethyl ether, and dried under vacuum to obtain the modified polyethylene glycol.

[0048] Experiment 1

[0049] Biodegradation test method (composting method); Test method: ISO14855-1:2012; Test temperature: 58℃; Compost container: 3.8 liters, 3 test containers, 3 standard containers, and 3 blank containers; Reference material: cellulose (HPLC); Compost source: self-made; Test period: 180 days; Test results are as follows:

[0050] Duration: 45 days

[0051]

[0052]

[0053] Duration: 90 days

[0054] Number of days: 135 days

[0055]

[0056] Duration: 180 days

[0057]

[0058] Test Report:

[0059]

[0060] As can be seen from the above, the bath ball prepared in this application has good biodegradability, is more environmentally friendly, and has a very broad market prospect.

[0061] Experiment 2

[0062] Comparative Example 1 (compared to Example 3, the modified starch was replaced with ordinary starch)

[0063] This invention provides a biodegradable bath sponge, such as... Figure 1 As shown, 60 parts of polylactic acid, 30 parts of EVA, 15 parts of polyhydroxybutyrate, 6 parts of chitosan, 5 parts of sericin, 25 parts of starch, and 10 parts of modified polyethylene glycol are weighed according to the specified ratio. The EVA has a relative density of 0.93 and a gloss level of 83. The raw materials are mixed evenly to obtain a mixed material. The mixed material is extruded at 210°C to obtain a mesh-like semi-finished product. The mesh-like semi-finished product is cooled, drawn, drained, drawn again, and wound to obtain a stretched semi-finished product. The stretched semi-finished product is cut and shaped to obtain a bath ball.

[0064] In this embodiment, the modified polyethylene glycol is prepared as follows: Under stirring, 1.5 parts by weight of polyethylene glycol are added dropwise to 5.5 parts by weight of sulfonium bromide. During the dropwise addition, the system temperature is maintained at 3°C, then raised to 55°C, and then added dropwise to 13 parts by weight of anhydrous diethyl ether. The mixture is filtered, washed, and dried. The product is dissolved in 8 parts by weight of N,N-dimethylformamide, and 0.7 parts by weight of 3-amino-1,2-propanediol and 0.9 parts by weight of diethylamine are added. The mixture is heated to 85°C and stirred for 4 hours. It is then extracted with dichloromethane, precipitated with anhydrous diethyl ether, and dried under vacuum to obtain the modified polyethylene glycol.

[0065] Comparative Example 2 (compared to Example 3, the modified polyethylene glycol was replaced with ordinary polyethylene glycol)

[0066] This invention provides a biodegradable bath sponge, such as... Figure 1As shown, 60 parts of polylactic acid, 30 parts of EVA, 15 parts of polyhydroxybutyrate, 6 parts of chitosan, 5 parts of sericin, 25 parts of modified starch, and 10 parts of polyethylene glycol are weighed according to the specified ratio. The EVA has a relative density of 0.93 and a gloss level of 83. The raw materials are mixed evenly to obtain a mixed material. The mixed material is extruded at 210°C to obtain a mesh-like semi-finished product. The mesh-like semi-finished product is cooled, drawn, drained, drawn again, and wound to obtain a stretched semi-finished product. The stretched semi-finished product is cut and shaped to obtain a bath ball.

[0067] In this embodiment, the modified starch is prepared as follows: 10 parts by weight of starch extracted from renewable plants (such as corn), 2 parts by weight of methacrylic acid, 1.5 parts by weight of hydrogen peroxide, and 1.5 parts by weight of sodium stearate are weighed and set aside. The methacrylic acid and sodium stearate are emulsified under ultrasonic conditions for 35 minutes to obtain an emulsion. The starch raw material is preheated at 70°C for 35 minutes under ultrasonic conditions and nitrogen protection at room temperature. The temperature is maintained at 70°C and hydrogen peroxide is added to react for 15 minutes to obtain a reactant. The emulsion is added to the reactant and the mixture is stirred at 1200-1800 r / min to carry out a chemical reaction for 25 minutes to obtain the modified starch.

[0068] Comparative Example 3 (compared to Example 3, the modified starch was replaced with ordinary starch and the modified polyethylene glycol was replaced with ordinary polyethylene glycol)

[0069] This invention provides a biodegradable bath sponge, such as... Figure 1 As shown, 60 parts of polylactic acid, 30 parts of EVA, 15 parts of polyhydroxybutyrate, 6 parts of chitosan, 5 parts of sericin, 25 parts of starch, and 10 parts of polyethylene glycol are weighed according to the specified ratio. The EVA has a relative density of 0.93 and a gloss level of 83. The raw materials are mixed evenly to obtain a mixed material. The mixed material is extruded at 210°C to obtain a mesh-like semi-finished product. The mesh-like semi-finished product is cooled, drawn, drained, drawn again, and wound to obtain a stretched semi-finished product. The stretched semi-finished product is cut and shaped to obtain a bath ball.

[0070] Comparative Example 4

[0071] A commercially available bath ball

[0072] The performance of the bath balls of Examples 1-6 and Comparative Examples 1-4 of this invention was tested and analyzed. The tensile properties were tested according to GB / T13022-1991 standard, and the results are shown in Table 1 below:

[0073] Table 1

[0074] Group Tensile strength (MPa) Elongation at break (%) Example 1 68.5 61.3 Example 2 68.8 61.9 Example 3 69.3 62.6 Example 4 69.1 62.5 Example 5 68.7 61.8 Example 6 75.6 68.5 Comparative Example 1 49.7 43.9 Comparative Example 2 48.5 43.5 Comparative Example 3 36.9 31.4 Comparative Example 4 37.4 32.1

[0075] The results above show that the bath ball prepared by this invention has good mechanical properties. By adding modified starch and modified polyethylene glycol, the two work synergistically to form a macromolecular network structure through mutual reaction between the materials, which further improves the mechanical properties of the bath ball. In the preparation of the bath ball, ultraviolet light irradiation treatment is applied during the mixing of the components to generate a three-dimensional network cross-linked structure between the raw materials and between the molecular structures inside the raw materials, which further improves the mechanical properties of the material.

[0076] Experiment 3

[0077] Single-factor experiments were conducted, changing only the ratio of modified starch to modified polyethylene glycol mixture in the raw material formulation. The amounts of other raw materials and preparation process conditions remained the same as in Example 3. Bath balls were prepared, and the performance of each group of bath balls was tested and analyzed. The test results are detailed in Table 2 below:

[0078] Table 2

[0079]

[0080] As shown in Table 2 above, adding a mixture of modified starch and modified polyethylene glycol to the system can significantly improve the mechanical properties of the bath ball. The optimal amount of the mixture of modified starch and modified polyethylene glycol is 30-40 parts by weight, with 35 parts by weight being the best.

[0081] Experiment 4

[0082] Single-factor experiments were conducted, changing only the mixing ratio of modified starch to modified polyethylene glycol to 1:1, 2:1, 2.5:1, 3:1, 3.5:1, and 1:3, while keeping the other raw material additions and preparation process conditions the same as in Example 3. Bath balls were prepared, and the performance of each group of bath balls was tested and analyzed. The results showed that when the mixing ratio of modified starch to modified polyethylene glycol was 1:1, 1:3, or 3.5:1, the tensile strength and elongation at break of the prepared bath balls were significantly lower than those prepared with the other mixing ratios. The bath balls prepared with a mixing ratio of modified starch to modified polyethylene glycol of 2:1 exhibited the best tensile strength and elongation at break.

[0083] It should be noted that, for the sake of simplicity, the foregoing embodiments are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to the present invention. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0084] It should be understood that the disclosed apparatus can be implemented in other ways, given the several embodiments provided in this application. For example, the apparatus embodiments described above are merely illustrative; the division of units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or communication connections shown or discussed may be through some interfaces; the indirect coupling or communication connections between devices or units may be telecommunications or other forms.

[0085] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0086] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still combine, add, delete, or otherwise adjust the features of the various embodiments of the present invention according to the circumstances without conflict or creative effort, thereby obtaining different technical solutions that do not fundamentally depart from the concept of the present invention. These technical solutions also fall within the scope of protection of the present invention.

Claims

1. A biodegradable bath sponge, characterized in that, It includes the following raw materials in parts by weight: 50-70 parts polylactic acid, 20-40 parts EVA, 10-20 parts polyhydroxybutyrate, 4-8 parts chitosan, 3-7 parts sericin, and 30-40 parts a mixture of modified starch and modified polyethylene glycol. The modified starch is prepared as follows: 8-12 parts by weight of starch extracted from renewable plants, 1-3 parts by weight of methacrylic acid, 1-2 parts by weight of hydrogen peroxide, and 1-2 parts by weight of sodium stearate are weighed and set aside. The methacrylic acid and sodium stearate are emulsified under ultrasonic conditions for 30-40 minutes to obtain an emulsion. The starch raw material is preheated at 60-80℃ for 30-40 minutes under ultrasonic conditions and nitrogen protection at room temperature. The temperature is maintained at 60-80℃, and hydrogen peroxide is added and reacted for 10-20 minutes to obtain a reactant. The emulsion is added to the reactant, and the mixture is stirred at 1200-1800 r / min for 20-30 minutes to obtain the modified starch. The modified polyethylene glycol is prepared as follows: Under stirring, 1-2 parts by weight of polyethylene glycol are added dropwise to 5-6 parts by weight of sulfonium bromide. During the dropwise addition, the system temperature is maintained at 2-4℃. The temperature is then raised to 50-60℃, and then added dropwise to 12-14 parts by weight of anhydrous diethyl ether. The mixture is filtered, washed, and dried. The product is dissolved in 7-10 parts by weight of N,N-dimethylformamide. 0.5-1 parts by weight of 3-amino-1,2-propanediol and 0.6-1.2 parts by weight of diethylamine are added. The mixture is heated to 80-90℃ and stirred for 3-5 hours. It is then extracted with dichloromethane, precipitated with anhydrous diethyl ether, and dried under vacuum to obtain the modified polyethylene glycol.

2. The biodegradable bath ball as described in claim 1, characterized in that, It includes the following raw materials in parts by weight: 55-65 parts polylactic acid, 25-35 parts EVA, 12-18 parts polyhydroxybutyrate, 5-7 parts chitosan, 4-6 parts sericin, and 32-38 parts a mixture of modified starch and modified polyethylene glycol.

3. The biodegradable bath ball as described in claim 2, characterized in that, The ingredients include the following raw materials in parts by weight: 60 parts polylactic acid, 30 parts EVA, 15 parts polyhydroxybutyrate, 6 parts chitosan, 5 parts sericin, and 35 parts a mixture of modified starch and modified polyethylene glycol.

4. The biodegradable bath sponge as described in claim 1, characterized in that, The weight ratio of the modified starch to the modified polyethylene glycol is 2-3:

1.

5. The method for preparing the biodegradable bath ball according to any one of claims 1-4, characterized in that, Includes the following steps: 1) Weigh each raw material according to the proportions; 2) Mix polylactic acid, EVA, polyhydroxybutyrate, chitosan, sericin, modified starch and modified polyethylene glycol, and stir at 1500-2000 r / min for 1-2 h until uniformly mixed to obtain a mixed material; 3) The mixed material is heated and melted at a temperature of 200-220℃, then molded and cooled to obtain a mesh-shaped semi-finished product. The heating and melting are carried out in a mesh stretching machine. 4) The mesh-type semi-finished product is stretched after being pulled, drained, pulled again, and wound up. 5) Cut and garnish the stretched semi-finished product to obtain a bath ball.

6. The method for preparing the biodegradable bath ball as described in claim 5, characterized in that, In step 2), after stirring for 10-20 minutes, irradiate with ultraviolet light for 20-30 seconds while stirring.

7. The method for preparing the biodegradable bath ball as described in claim 6, characterized in that, The ultraviolet irradiation treatment uses an ultraviolet irradiation crosslinking device with a specific light source, which is either a thermionic excitation medium-pressure mercury arc lamp or a microwave excitation electrodeless lamp with gallium added (V-shaped lamp).

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