Laundry condensate bead packaging film and preparation method thereof

Abstract

The invention relates to the field of detergents, in particular to a laundry condensate bead packaging film and a preparation method thereof. The laundry condensate bead packaging film provided by the invention is composed of the following components in percentage by mass: 25-35% of polylactic acid; 5-7% of a plasticizer; 3-4% of a surfactant; 2-5% of a stabilizer; and 1-2% of carbon black. The preparation method of the laundry condensate bead packaging film comprises the two steps of S1 amidation reaction and S2 laundry condensate bead packaging film preparation, the reaction temperature, pressure, solvent proportion and reaction time need to be strictly controlled in any step, and smooth reaction and product quality are ensured; the preparation method is simple in reaction operation, simple in post-treatment, pollution-free in reaction by-product and environment-friendly.

Description

Technical Field

[0001] The invention relates to the field of detergents, and in particular to a packaging film for laundry beads and a preparation method thereof. Background Art

[0002] Laundry beads are a new type of clothing care product that concentrates laundry detergents such as laundry detergent and softener into capsules. The emergence of laundry beads meets the needs of modern consumers for convenient, efficient and environmentally friendly laundry care products. As the outer packaging of laundry beads, the packaging film of laundry beads should have good water solubility, biodegradability and environmental protection. The packaging film of laundry beads usually uses polyvinyl alcohol (PVA), which is a safe high-molecular organic matter that is harmless to the human body and has no side effects. However, the use of PVA as the packaging film of laundry beads still has certain defects. PVA is sensitive to humidity and is a hygroscopic material that easily absorbs water vapor in the air. In a high humidity environment, the PVA film may become sticky or even dissolve directly, causing the contents of the laundry beads to leak; the dissolution rate of the polyvinyl alcohol film is not only related to its own composition and thickness, but also affected by external conditions such as water temperature. This may lead to inconsistent dissolution rates of laundry beads in the washing machine, thereby affecting the cleaning effect. In addition, the packaging film of laundry beads should also have good antistatic properties, glossiness and transparency. Summary of the invention

[0003] In view of the above-mentioned existing technical problems, a laundry condenser bead packaging film and a preparation method thereof are provided. The laundry condenser bead packaging film prepared by this method has excellent antistatic properties, moisture resistance, glossiness, hydrolysis resistance, tensile strength and tear strength.

[0004] The present invention discloses a packaging film for laundry beads, which is composed of the following components in percentage by mass:

[0005] Polylactic acid 25-35%; plasticizer 5-7%; surfactant 3-4%; stabilizer 2-5%; carbon black 1-2%.

[0006] Preferably, the plasticizer is polyethylene glycol; the surfactant is fatty alcohol polyoxyethylene ether; and the stabilizer is sodium chloride.

[0007] The present invention also discloses a method for preparing a laundry condensate bead packaging film, comprising the following steps:

[0008] S1 Amidation reaction: polylactic acid and caprolactam are placed in a vacuum dryer for drying respectively, the dried polylactic acid is added to a reactor, and dimethyl sulfoxide is added for stirring and dissolving, and caprolactam is added and stirred when there are no solid particles in the reactor. After the dissolution is complete, the reactor is replaced with nitrogen three times, and then a catalyst is added. After the addition is completed, nitrogen is replaced three times again, the reactor is sealed, and the temperature and pressure are increased to perform an amidation reaction. After the reaction is completed, a reaction solution is obtained, and the reaction solution is concentrated under reduced pressure to obtain a solid. The obtained solid is transferred to a beaker, and chloroform is added to completely dissolve it, and then the dissolved solution is added dropwise to methanol to produce a precipitate, and then the filter cake is collected by vacuum filtration, and the filter cake is dried to obtain a polylactic acid amidate;

[0009] S2 Preparation of packaging film for laundry beads: Add the polylactic acid amide, carbon black, polyethylene glycol, fatty alcohol polyoxyethylene ether and sodium chloride obtained in step S1 to a mixer in sequence, add deionized water and stir to mix, heat to react after being evenly mixed, filter while hot after the reaction is completed, collect the filtrate, introduce the filtrate into a mold, cool and solidify to obtain a packaging film for laundry beads.

[0010] Preferably, in the amidation reaction step S1, the drying temperature of the polylactic acid is 45-50°C; the drying temperature of caprolactam is 60-65°C.

[0011] Preferably, in the amidation reaction step S1, the mass ratio of the polylactic acid to dimethyl sulfoxide is 1:(5-10).

[0012] Preferably, in the amidation reaction step S1, the catalyst is a mixture of sodium methoxide and sodium glutamate.

[0013] Preferably, in the amidation reaction step S1, the mass ratio of the polylactic acid to sodium methoxide is 1:(0.01-0.02); the mass ratio of the polylactic acid to sodium glutamate is 1:(0.015-0.02).

[0014] Preferably, in the amidation reaction step S1, the reaction temperature is 180-200° C.; the reaction pressure is 5-7 MPa; and the reaction time is 3-5 h.

[0015] Preferably, in the amidation reaction step S1, the temperature of the methanol needs to be between -5 and 0°C.

[0016] Preferably, in the step S2 of preparing the laundry beads packaging film, the mass ratio of the polylactic acid amide to deionized water is 1:(25-30); the temperature of the heating reaction is 80-100°C; the reaction time is 1-2h; and the cooling stability during the cooling and curing process is 10-15°C.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention provides a packaging film for laundry beads and a preparation method thereof, wherein polylactic acid is first subjected to an amidation reaction to obtain polylactic acid amidate, and then the compound is used as a base material, and some auxiliary agents are added to prepare the packaging film for laundry beads. Polylactic acid has good biocompatibility, degradability and corrosion resistance, but relatively poor water solubility. Therefore, polylactic acid is first converted into polylactic acid amidate before preparing the packaging film for laundry beads, which effectively solves the disadvantage of poor water solubility of polylactic acid and retains the original advantages of polylactic acid.

[0019] In the preparation method provided by the present invention, the reaction temperature, pressure, solvent ratio and reaction time need to be strictly controlled to ensure the smooth progress of the reaction and the quality of the product; this preparation method has simple reaction operation, simple post-treatment, no pollution from reaction by-products, and is environmentally friendly.

[0020] The laundry condensate bead packaging film prepared by the invention has good compatibility and degradability, good glossiness and transparency, and can also be anti-corrosive and anti-static. DETAILED DESCRIPTION

[0021] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0022] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0023] Embodiment 1: A laundry condensate packaging film, comprising the following components in percentage by mass:

[0024] Polylactic acid 25%; plasticizer 5%; surfactant 3%; stabilizer 2%; carbon black 1%.

[0025] The plasticizer is polyethylene glycol; the surfactant is fatty alcohol polyoxyethylene ether; and the stabilizer is sodium chloride.

[0026] A method for preparing a laundry condensate bead packaging film comprises the following steps:

[0027] S1 Amidation reaction: PLA and caprolactam are placed in a vacuum dryer for drying respectively. The drying temperature of PLA is 45°C and the drying temperature of caprolactam is 60°C. Both PLA and caprolactam need to be dried for 20 to 24 hours. The dried polylactic acid is added to the reactor, and then dimethyl sulfoxide is added for stirring and dissolving, the mass ratio of polylactic acid to dimethyl sulfoxide is 1:5, and when there are no solid particles in the reactor, caprolactam is added and continued to stir. After complete dissolution, the reactor is replaced with nitrogen three times, and then sodium methoxide and sodium glutamate are added, the mass ratio of polylactic acid to sodium methoxide is 1:0.01; the mass ratio of polylactic acid to sodium glutamate is 1:0.015; after the addition is completed, nitrogen replacement is performed three times, the reactor is sealed and then heated to 180°C, and the pressure is increased to 5MPa for amidation reaction, the reaction time is 3h, and the reaction liquid is obtained after the reaction is completed. The reaction liquid is concentrated under reduced pressure to obtain a solid, the obtained solid is transferred to a beaker, chloroform is added to completely dissolve it, and then the dissolved liquid is dropped into methanol to produce precipitation, wherein the temperature of the methanol needs to be kept at 0°C; then the filter cake is collected by vacuum filtration, and the filter cake is dried to obtain polylactic acid amidate.

[0028] S2 Preparation of packaging film for laundry beads: Add the polylactic acid amide, carbon black, polyethylene glycol, fatty alcohol polyoxyethylene ether and sodium chloride obtained in step S1 to a mixer in sequence, add deionized water and stir to mix, the mass ratio of polylactic acid amide to deionized water is 1:25; after being evenly mixed, heat to react at a temperature of 80°C and a reaction time of 1h. During the reaction, the reaction liquid needs to be stirred continuously. After the reaction is completed, filter while hot, collect the filtrate, introduce the filtrate into a mold, cool and solidify to form, and the cooling and solidification temperature is 15°C to finally obtain a packaging film for laundry beads.

[0029] Embodiment 2: A laundry condensate packaging film, comprising the following components in percentage by mass:

[0030] Polylactic acid 27%; plasticizer 5.5%; surfactant 3.2%; stabilizer 2.5%; carbon black 1.2%.

[0031] The plasticizer is polyethylene glycol; the surfactant is fatty alcohol polyoxyethylene ether; and the stabilizer is sodium chloride.

[0032] A method for preparing a laundry condensate bead packaging film comprises the following steps:

[0033] S1 Amidation reaction: PLA and caprolactam are placed in a vacuum dryer for drying respectively. The drying temperature of PLA is 45°C and the drying temperature of caprolactam is 60°C. Both PLA and caprolactam need to be dried for 20 to 24 hours. The dried polylactic acid is added to the reactor, and then dimethyl sulfoxide is added for stirring and dissolving, the mass ratio of polylactic acid to dimethyl sulfoxide is 1:6, and when there are no solid particles in the reactor, caprolactam is added and continued to stir. After complete dissolution, the reactor is replaced with nitrogen three times, and then sodium methoxide and sodium glutamate are added, the mass ratio of polylactic acid to sodium methoxide is 1:0.012; the mass ratio of polylactic acid to sodium glutamate is 1:0.016; after the addition is completed, nitrogen replacement is performed three times, the reactor is sealed and then the temperature is increased to 185°C, and the pressure is increased to 5.5MPa for amidation reaction, the reaction time is 3.5h, and the reaction liquid is obtained after the reaction is completed. The reaction liquid is concentrated under reduced pressure to obtain a solid, the obtained solid is transferred to a beaker, chloroform is added to completely dissolve it, and then the dissolved liquid is dropped into methanol to produce precipitation, wherein the temperature of the methanol needs to be kept at -1°C; then the filter cake is collected by vacuum filtration, and the filter cake is dried to obtain polylactic acid amidate.

[0034] S2 Preparation of packaging film for laundry beads: Add the polylactic acid amide, carbon black, polyethylene glycol, fatty alcohol polyoxyethylene ether and sodium chloride obtained in step S1 to a mixer in sequence, add deionized water and stir to mix, the mass ratio of polylactic acid amide to deionized water is 1:26; after being evenly mixed, heat to react, the heating reaction temperature is 85°C, and the reaction time is 1.2h. The reaction liquid needs to be stirred continuously during the reaction. After the reaction is completed, it needs to be filtered while hot, the filtrate is collected, and the filtrate is introduced into a mold, cooled and solidified to form, the cooling and solidification temperature is 14°C, and finally a packaging film for laundry beads is obtained.

[0035] Embodiment 3: A laundry condensate packaging film, comprising the following components in percentage by mass:

[0036] Polylactic acid 29%; plasticizer 6%; surfactant 3.4%; stabilizer 3%; carbon black 1.4%.

[0037] The plasticizer is polyethylene glycol; the surfactant is fatty alcohol polyoxyethylene ether; and the stabilizer is sodium chloride.

[0038] A method for preparing a laundry condensate bead packaging film comprises the following steps:

[0039] S1 Amidation reaction: PLA and caprolactam are placed in a vacuum dryer for drying respectively. The drying temperature of PLA is 47°C and the drying temperature of caprolactam is 63°C. Both PLA and caprolactam need to be dried for 20 to 24 hours. The dried polylactic acid is added to the reactor, and then dimethyl sulfoxide is added for stirring and dissolving, the mass ratio of polylactic acid to dimethyl sulfoxide is 1:7, and caprolactam is added and stirred when there are no solid particles in the reactor. After the dissolution is complete, the reactor is replaced with nitrogen three times, and then sodium methoxide and sodium glutamate are added, the mass ratio of polylactic acid to sodium methoxide is 1:0.014; the mass ratio of polylactic acid to sodium glutamate is 1:0.017; after the addition is completed, nitrogen replacement is performed three times, the reactor is sealed and then the temperature is increased to 190°C, and the pressure is increased to 6MPa for amidation reaction, the reaction time is 4h, and the reaction liquid is obtained after the reaction is completed. The reaction liquid is concentrated under reduced pressure to obtain a solid, the obtained solid is transferred to a beaker, chloroform is added to completely dissolve it, and then the dissolved liquid is dropped into methanol to produce precipitation, wherein the temperature of the methanol needs to be kept at -2°C; then the filter cake is collected by vacuum filtration, and the filter cake is dried to obtain polylactic acid amidate.

[0040] S2 Preparation of packaging film for laundry beads: Add the polylactic acid amide, carbon black, polyethylene glycol, fatty alcohol polyoxyethylene ether and sodium chloride obtained in step S1 to a mixer in sequence, add deionized water and stir to mix, the mass ratio of polylactic acid amide to deionized water is 1:27; after being evenly mixed, heat to react, the heating reaction temperature is 90°C, and the reaction time is 1.4h. The reaction liquid needs to be stirred continuously during the reaction, and after the reaction is completed, it needs to be filtered while hot, the filtrate is collected, and the filtrate is introduced into a mold, cooled and solidified to form, the cooling and solidification temperature is 13°C, and finally a packaging film for laundry beads is obtained.

[0041] Example 4: A laundry condensate packaging film, comprising the following components in percentage by mass:

[0042] Polylactic acid 31%; plasticizer 6.5%; surfactant 3.6%; stabilizer 3.5%; carbon black 1.6%.

[0043] The plasticizer is polyethylene glycol; the surfactant is fatty alcohol polyoxyethylene ether; and the stabilizer is sodium chloride.

[0044] A method for preparing a laundry condensate bead packaging film comprises the following steps:

[0045] S1 Amidation reaction: PLA and caprolactam are placed in a vacuum dryer for drying respectively. The drying temperature of PLA is 47°C and the drying temperature of caprolactam is 63°C. Both PLA and caprolactam need to be dried for 20 to 24 hours. The dried polylactic acid is added to the reactor, and then dimethyl sulfoxide is added for stirring and dissolving, the mass ratio of polylactic acid to dimethyl sulfoxide is 1:8, and caprolactam is added and stirred when there are no solid particles in the reactor. After the dissolution is complete, the reactor is replaced with nitrogen three times, and then sodium methoxide and sodium glutamate are added, the mass ratio of polylactic acid to sodium methoxide is 1:0.016; the mass ratio of polylactic acid to sodium glutamate is 1:0.018; after the addition is completed, nitrogen replacement is performed three times, the reactor is sealed and then the temperature is increased to 195°C, and the pressure is increased to 6.5MPa for amidation reaction, the reaction time is 4.5h, and the reaction liquid is obtained after the reaction is completed. The reaction liquid is concentrated under reduced pressure to obtain a solid, the obtained solid is transferred to a beaker, chloroform is added to completely dissolve it, and then the dissolved liquid is added dropwise to methanol to produce precipitation, wherein the temperature of the methanol needs to be kept at -3°C; then the filter cake is collected by vacuum filtration, and the filter cake is dried to obtain polylactic acid amidate.

[0046] S2 Preparation of packaging film for laundry beads: Add the polylactic acid amide, carbon black, polyethylene glycol, fatty alcohol polyoxyethylene ether and sodium chloride obtained in step S1 to a mixer in sequence, add deionized water and stir to mix, the mass ratio of polylactic acid amide to deionized water is 1:28; after being evenly mixed, heat to react, the heating reaction temperature is 93°C, and the reaction time is 1.6h. The reaction liquid needs to be stirred continuously during the reaction. After the reaction is completed, it needs to be filtered while hot, the filtrate is collected, and the filtrate is introduced into a mold, cooled and solidified to form, the cooling and solidification temperature is 12°C, and finally a packaging film for laundry beads is obtained.

[0047] Example 5: A laundry condensate packaging film, comprising the following components in percentage by mass:

[0048] Polylactic acid 33%; plasticizer 6.7%; surfactant 3.8%; stabilizer 3.7%; carbon black 1.8%.

[0049] The plasticizer is polyethylene glycol; the surfactant is fatty alcohol polyoxyethylene ether; and the stabilizer is sodium chloride.

[0050] A method for preparing a laundry condensate bead packaging film comprises the following steps:

[0051] S1 Amidation reaction: PLA and caprolactam are placed in a vacuum dryer for drying respectively. The drying temperature of PLA is 50°C and the drying temperature of caprolactam is 65°C. Both PLA and caprolactam need to be dried for 20 to 24 hours. The dried polylactic acid is added to the reactor, and then dimethyl sulfoxide is added for stirring and dissolving, the mass ratio of polylactic acid to dimethyl sulfoxide is 1:9, and when there are no solid particles in the reactor, caprolactam is added and continued to stir. After complete dissolution, the reactor is nitrogen replaced 3 times, and then sodium methoxide and sodium glutamate are added, the mass ratio of polylactic acid to sodium methoxide is 1:0.018; the mass ratio of polylactic acid to sodium glutamate is 1:0.019; after the addition is completed, nitrogen replacement is performed 3 times, the reactor is sealed and then the temperature is increased to 200°C, and the pressure is increased to 7MPa for amidation reaction, the reaction time is 5h, and after the reaction is completed, a reaction solution is obtained, and the reaction solution is concentrated under reduced pressure to obtain a solid, the obtained solid is transferred to a beaker, chloroform is added to completely dissolve it, and then the dissolved solution is dropped into methanol to produce precipitation, wherein the temperature of the methanol needs to be kept at -4°C; then the filter cake is collected by vacuum filtration, and the filter cake is dried to obtain polylactic acid amidate.

[0052] S2 Preparation of packaging film for laundry beads: Add the polylactic acid amide, carbon black, polyethylene glycol, fatty alcohol polyoxyethylene ether and sodium chloride obtained in step S1 to a mixer in sequence, add deionized water and stir to mix, the mass ratio of polylactic acid amide to deionized water is 1:29; after being evenly mixed, heat to react, the heating reaction temperature is 96°C, and the reaction time is 1.8h. During the reaction, the reaction liquid needs to be stirred continuously. After the reaction is completed, it needs to be filtered while hot, the filtrate is collected, and the filtrate is introduced into a mold, cooled and solidified to form, the cooling and solidification temperature is 11°C, and finally a packaging film for laundry beads is obtained.

[0053] Example 6: A laundry condensate packaging film, comprising the following components in percentage by mass:

[0054] Polylactic acid 35%; plasticizer 7%; surfactant 4%; stabilizer 4%; carbon black 2%.

[0055] The plasticizer is polyethylene glycol; the surfactant is fatty alcohol polyoxyethylene ether; and the stabilizer is sodium chloride.

[0056] A method for preparing a laundry condensate bead packaging film comprises the following steps:

[0057] S1 Amidation reaction: PLA and caprolactam are placed in a vacuum dryer for drying respectively. The drying temperature of PLA is 50°C and the drying temperature of caprolactam is 65°C. Both PLA and caprolactam need to be dried for 20 to 24 hours. The dried polylactic acid is added to the reactor, and then dimethyl sulfoxide is added for stirring and dissolving, the mass ratio of polylactic acid to dimethyl sulfoxide is 1:10, and when there are no solid particles in the reactor, caprolactam is added and continued to stir. After complete dissolution, the reactor is replaced with nitrogen three times, and then sodium methoxide and sodium glutamate are added, the mass ratio of polylactic acid to sodium methoxide is 1:0.02; the mass ratio of polylactic acid to sodium glutamate is 1:0.02; after the addition is completed, nitrogen replacement is performed three times, the reactor is sealed and then the temperature is increased to 200°C, and the pressure is increased to 7MPa for amidation reaction, the reaction time is 5h, and after the reaction is completed, a reaction solution is obtained, and the reaction solution is concentrated under reduced pressure to obtain a solid, the obtained solid is transferred to a beaker, chloroform is added to completely dissolve it, and then the dissolved solution is added dropwise to methanol to produce precipitation, wherein the temperature of the methanol needs to be kept at -5°C; then the filter cake is collected by vacuum filtration, and the filter cake is dried to obtain polylactic acid amidate.

[0058] S2 Preparation of packaging film for laundry beads: Add the polylactic acid amide, carbon black, polyethylene glycol, fatty alcohol polyoxyethylene ether and sodium chloride obtained in step S1 to a mixer in sequence, add deionized water and stir to mix, the mass ratio of polylactic acid amide to deionized water is 1:30; after being evenly mixed, heat to react, the heating reaction temperature is 100°C, the reaction time is 2h, the reaction liquid needs to be stirred continuously during the reaction, after the reaction is completed, filter while hot, collect the filtrate, introduce the filtrate into a mold, cool and solidify to form, the cooling and solidification temperature is 10°C, and finally the packaging film for laundry beads is obtained.

[0059] Comparative Example 1: A laundry condensate packaging film, comprising the following components in percentage by mass:

[0060] Polylactic acid 33%; plasticizer 6.7%; surfactant 3.8%; stabilizer 3.7%; carbon black 1.8%. The plasticizer is polyethylene glycol; the surfactant is fatty alcohol polyoxyethylene ether; the stabilizer is sodium chloride.

[0061] In the preparation method, the S1 amidation reaction step is eliminated, and polylactic acid is directly used as the raw material for preparing the packaging film of the laundry beads.

[0062] Add polylactic acid, carbon black, polyethylene glycol, fatty alcohol polyoxyethylene ether and sodium chloride to a mixer in sequence, add deionized water and stir to mix, the mass ratio of polylactic acid amide to deionized water is 1:29; after being evenly mixed, heat to react, the heating reaction temperature is 120°C, the reaction time is 1.8h, the reaction liquid needs to be stirred continuously during the reaction, after the reaction is completed, filter while hot, collect the filtrate, introduce the filtrate into a mold, cool and solidify to form, the cooling and solidification temperature is 11°C, and finally the laundry beads packaging film is obtained.

[0063] Comparative Example 2: A laundry condensate packaging film, comprising the following components in percentage by mass:

[0064] Polylactic acid 33%; plasticizer 6.7%; surfactant 3.8%; stabilizer 3.7%; carbon black 1.8%.

[0065] The plasticizer is polyethylene glycol; the surfactant is fatty alcohol polyoxyethylene ether; and the stabilizer is sodium chloride.

[0066] A method for preparing a laundry condensate bead packaging film comprises the following steps:

[0067] The amidation reaction of S1 is the same as that of Example 5.

[0068] S2 Preparation of packaging film for laundry beads: Add the polylactic acid amide, carbon black, polyethylene glycol, fatty alcohol polyoxyethylene ether and sodium chloride obtained in step S1 to a mixer in sequence, add deionized water and stir to mix, the mass ratio of polylactic acid amide to deionized water is 1:29; after being evenly mixed, heat to 120°C and filter directly after all the raw materials are dissolved, collect the filtrate, introduce the filtrate into a mold, cool and solidify to form, the cooling and solidifying temperature is 11°C, and finally the packaging film for laundry beads is obtained.

[0069] Comparative Example 3: Commercially available laundry detergent packaging film.

[0070] The performance of the laundry beads packaging films prepared in Examples 1 to 6 and Comparative Examples 1 to 3 was tested, and the test results are shown in the following table:

[0071]

[0072] From the test results in the above table, it can be seen that Examples 5 and 6 have the highest tensile strength, tear strength and transmittance, and the lowest weight gain and surface resistance, indicating that the laundry beads packaging films prepared in Examples 5 and 6 have the best performance.

[0073] Comparative Example 3 is a commercially available laundry condenser bead packaging film, which has lower tensile strength, tear strength and light transmittance than those in the examples, while its weight gain rate and surface resistance are higher than those in the examples. This indicates that the laundry condenser bead packaging film prepared by the present invention is more pressure-resistant and tear-resistant, more moisture-resistant, more anti-static, more glossy and more transparent, and has a better appearance than the commercially available laundry condenser bead packaging film.

[0074] Compared with Example 5, Comparative Example 1 does not subject polylactic acid to amidation treatment, but directly uses it as a raw material to prepare a laundry condenser bead packaging film. From the data in the above table, it can be seen that the laundry condenser bead packaging film prepared in Comparative Example 1 is slightly inferior to the laundry condenser bead packaging film prepared in Example 5 in terms of tensile strength, tear strength, surface resistance and light transmittance, but the weight gain rate of Comparative Example 1 is much lower than that of Example 5. The weight gain rate represents the moisture absorption capacity. The higher the weight gain rate, the stronger the moisture absorption capacity, and the worse the moisture resistance. Because polylactic acid itself is a substance with relatively poor water solubility, the laundry condenser bead packaging film directly prepared without amidation treatment will have poor water solubility, so the weight gain rate of Comparative Example 1 will be much lower than that of Example 5.

[0075] Compared with Example 5, Comparative Example 2 eliminates the heating and stirring steps in the preparation process of S2 laundry condensate packaging film, and directly pours it into the mold for cooling and solidification after all materials are added. From the experimental test results of the final product, the tensile strength, tear strength and light transmittance of the finished product obtained in Comparative Example 2 are lower than those in Example 5, and the weight gain rate and surface resistance are higher than those in Example 5, which shows that eliminating the heating and stirring steps will have a greater impact on the performance of the final product.

[0076] The solubility properties of the laundry beads packaging films prepared in Examples 1 to 6 and Comparative Examples 1 to 3 were tested at 25 to 30° C. The test results are shown in the following table:

[0077] Examples and Comparative Examples Water dissolution starting time (s) Complete dissolution time (s) Example 1 75 26 Example 2 78 25 Example 3 80 24 Example 4 81 22 Example 5 83 22 Example 6 83 22 Comparative Example 1 Insoluble Insoluble Comparative Example 2 60 20 Comparative Example 3 65 180

[0078] From the above table data, it can be seen that the water dissolution start time of Examples 1 to 6 is later than that of Comparative Examples 1 to 3, but the complete dissolution time is shorter than that of the Comparative Examples. This is because the laundry condenser bead packaging film prepared by Examples 1 to 6 has a higher moisture resistance, so the time to start water dissolution will be relatively long, but because the laundry condenser bead packaging film has good hydrolysis, it will dissolve completely very quickly after starting to dissolve. Comparative Example 1 is almost insoluble because the base material polylactic acid of the raw material has poor water solubility, and the laundry condenser bead packaging film prepared using this material as the base material will also have poor hydrolysis.

[0079] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A packaging film for laundry beads, characterized in that: It is composed of the following components in percentage by mass: Polylactic acid 25-35%; plasticizer 5-7%; surfactant 3-4%; stabilizer 2-5%; carbon black 1-2%.

2. A laundry condensate packaging film according to claim 1, characterized in that: The plasticizer is polyethylene glycol; the surfactant is fatty alcohol polyoxyethylene ether; and the stabilizer is sodium chloride.

3. A method for preparing a packaging film for laundry beads, characterized in that: The method comprises the following preparation steps: S1 Amidation reaction: polylactic acid and caprolactam are placed in a vacuum dryer for drying respectively, the dried polylactic acid is added to a reactor, and dimethyl sulfoxide is added for stirring and dissolving, and caprolactam is added and stirred when there are no solid particles in the reactor. After the dissolution is complete, the reactor is replaced with nitrogen three times, and then a catalyst is added. After the addition is completed, nitrogen is replaced three times again, the reactor is sealed, and then the temperature and pressure are increased to perform an amidation reaction. After the reaction is completed, a reaction solution is obtained, and the reaction solution is concentrated under reduced pressure to obtain a solid. The obtained solid is transferred to a beaker, and chloroform is added to completely dissolve it, and then the dissolved solution is added dropwise to methanol to produce a precipitate, and then the filter cake is collected by vacuum filtration, and the filter cake is dried to obtain a polylactic acid amidate; S2 Preparation of packaging film for laundry beads: Add the polylactic acid amide, carbon black, polyethylene glycol, fatty alcohol polyoxyethylene ether and sodium chloride obtained in step S1 to a mixer in sequence, add deionized water and stir to mix, heat to react after being evenly mixed, filter while hot after the reaction is completed, collect the filtrate, introduce the filtrate into a mold, cool and solidify to obtain a packaging film for laundry beads.

4. The method for preparing a laundry condensate packaging film according to claim 3, characterized in that: In the amidation reaction step S1, the drying temperature of the polylactic acid is 45-50°C; the drying temperature of caprolactam is 60-65°C.

5. The method for preparing a packaging film for laundry beads according to claim 3, characterized in that: In the amidation reaction step S1, the mass ratio of the polylactic acid to dimethyl sulfoxide is 1:(5-10).

6. The method for preparing a laundry beads packaging film according to claim 3, characterized in that: In the S1 amidation reaction step, the catalyst is a mixture of sodium methoxide and sodium glutamate.

7. The method for preparing a packaging film for laundry beads according to claim 3, characterized in that: In the amidation reaction step S1, the mass ratio of the polylactic acid to sodium methoxide is 1:(0.01-0.02); the mass ratio of the polylactic acid to sodium glutamate is 1:(0.015-0.02).

8. The method for preparing a packaging film for laundry beads according to claim 3, characterized in that: In the S1 amidation reaction step, the reaction temperature is 180-200° C.; the reaction pressure is 5-7 MPa; and the reaction time is 3-5 h.

9. The method for preparing a packaging film for laundry beads according to claim 3, characterized in that: In the amidation reaction step S1, the temperature of the methanol needs to be between -5 and 0°C.

10. The method for preparing a packaging film for laundry beads according to claim 3, characterized in that: In the S2 laundry beads packaging film preparation step, the mass ratio of the polylactic acid amide to deionized water is 1: (25-30); the heating reaction temperature is 80-100°C; the reaction time is 1-2h; and the cooling stability during the cooling and curing process is 10-15°C.

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