Low-temperature thermoplastic film and production method thereof

Abstract

The invention belongs to the technical field of thermoplastic molds. The invention provides a low-temperature thermoplastic film and a production method thereof, and the method comprises the following steps: S1, uniformly mixing 100 parts by weight of polyvinyl chloride resin, 11.7-12.2 parts by weight of di-n-octyl phthalate, 3.5-4 parts by weight of epoxy triglyceride, 8.5-9 parts by weight of a stabilizer, 1.2-1.5 parts by weight of thiosalicylic acid modified chlorinated paraffin and 1.5-1.8 parts by weight of ethylene bis stearamide to obtain a mixture; s2, putting the mixture obtained in the step S1 into a double-screw extruder, and extruding and granulating to obtain a granular material; and S3, putting the granules obtained in S2 into an injection molding machine, and carrying out injection molding to obtain the low-temperature thermoplastic film. The addition amount of the epoxy triglyceride is increased, so that the softening temperature of the prepared low-temperature thermoplastic film is reduced, and the tensile strength of the low-temperature thermoplastic film is further improved.

Description

Technical Field

[0001] This invention belongs to the field of thermoplastic molding technology, specifically relating to a low-temperature thermoplastic film and its production method. Background Technology

[0002] In the past, plaster casts were widely used in clinical treatments such as fractures and orthotics due to their malleability and relatively simple application. However, with continuous technological advancements and in-depth medical research, limitations of plaster casts have become apparent, such as their heavy weight and poor breathability. Against this backdrop, polymer fixation materials emerged and, with their numerous advantages, have gradually replaced traditional plaster casts, becoming the more commonly used choice in clinical practice. Among the many polymer fixation materials, low-temperature thermoplastic polymer resins stand out, playing a crucial role in various clinical settings due to their excellent properties. These low-temperature thermoplastic polymer resins possess good malleability; at relatively low temperatures, they become soft and easily shaped. Medical staff can precisely mold them into the desired shape according to the patient's specific condition and body part, thus providing stable and conforming support for fractures or areas requiring orthotics.

[0003] Beyond its applications in fracture treatment and orthopedics, low-temperature thermoplastic polymer resin materials have demonstrated unique value in radiotherapy. Radiotherapy, a common and crucial method for treating tumors, often faces the challenge of varying target shapes. Due to differences in tumor location, size, and overall health among patients, radiotherapy target areas exhibit diverse morphologies. This necessitates a custom-designed fixation mold tailored to the specific target shape to ensure accuracy and effectiveness. The use of low-temperature thermoplastic polymer resin materials, such as polyvinyl chloride (PVC) thermoplastic film, can create these fixation molds, immobilizing the patient and improving radiotherapy accuracy.

[0004] In existing technologies, polyvinyl chloride resin is used as the main material, with the addition of plasticizers di-n-octyl phthalate and epoxy triglyceride, as well as stabilizers, to prepare a low-temperature thermoplastic film through a thermoplastic molding process. Depending on the actual needs, the amount of epoxy triglyceride added can be increased to lower the softening temperature of the resulting low-temperature thermoplastic film. As the amount of epoxy triglyceride increases, the softening temperature of the resulting low-temperature thermoplastic film continues to decrease; however, this also leads to a decrease in its tensile strength. Summary of the Invention

[0005] To address the problems existing in the background art, the present invention provides a low-temperature thermoplastic film and its production method, which increases the amount of epoxy glycerol triester added to reduce the softening temperature of the obtained low-temperature thermoplastic film while further improving its tensile strength.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a method for producing a low-temperature thermoplastic film, comprising the following steps:

[0007] S1. By weight, 100 parts of polyvinyl chloride resin, 11.7-12.2 parts of di-n-octyl phthalate, 3.5-4 parts of epoxy glyceryl triester, 8.5-9 parts of stabilizer, 1.2-1.5 parts of thiosalicylic acid modified chlorinated paraffin, and 1.5-1.8 parts of ethylene bis-stearamide are mixed to obtain a mixture.

[0008] S2. The mixture obtained in S1 is fed into a twin-screw extruder and extruded and granulated to obtain granules;

[0009] S3. The granules obtained in S2 are put into an injection molding machine and injection molded to obtain the low-temperature thermoplastic film.

[0010] Furthermore, the preparation method of the thiosalicylic acid modified chlorinated paraffin is as follows:

[0011] A1. By weight, add 480-510 parts of acetone and 50 parts of chlorinated paraffin to the reactor, stir to dissolve, then add 37-42 parts of thiosalicylic acid and 42-45 parts of potassium carbonate, and react under inert gas protection to obtain the reactants.

[0012] A2. Extract the reactants obtained in A1 with ethanol, and then dry them under vacuum to obtain the extract.

[0013] A3. Pour the extract obtained in A2 into tetrahydrofuran, adjust the pH value to 4-4.2, then pour it into ethanol for extraction, and then vacuum dry to obtain the final product.

[0014] Furthermore, in A1, the reaction temperature is 50±2℃ and the reaction time is 12-13h.

[0015] Furthermore, in both A2 and A3, the drying temperature is 100±2℃ and the drying time is 2-2.5h.

[0016] Furthermore, in A3, the pH value is adjusted using hydrochloric acid.

[0017] Further, in S1, the stabilizer includes a composite lead salt, stearic acid, zinc stearate and calcium stearate, and the mass ratio of the four is (4.5-5):1:1:(1.5-2).

[0018] Furthermore, in S2, granulation is performed by extrusion at a temperature of 140-145°C.

[0019] Furthermore, in S3, injection molding is performed at a temperature of 140-145°C.

[0020] Secondly, the present invention provides a low-temperature thermoplastic film, which is produced by the above-described production method.

[0021] This application has the following beneficial effects:

[0022] This invention also introduces thiosalicylic acid-modified chlorinated paraffin and ethylene bis-stearamide; the two long-chain alkyl groups in the ethylene bis-stearamide molecule self-assemble into a layered crystal structure in the molten state, interspersed between the polyvinyl chloride resin molecular chains swollen by epoxy glycerol triester, forming physical cross-linking points, restricting chain segment slippage, and thus improving tensile strength.

[0023] The layered crystal network of ethylene bis-stearamide encapsulates thiosalicylic acid-modified chlorinated paraffin particles, transforming them from "defect sources" into "reinforcing nodes" and suppressing the aggregation effect of thiosalicylic acid-modified chlorinated paraffin in the system. The thiosalicylic acid-modified chlorinated paraffin retains carboxyl groups, which can interact with the amide groups of ethylene bis-stearamide through hydrogen bonding to construct a stable interfacial transition layer, enhancing the adhesion between the two phases and thus achieving a synergistic improvement in tensile strength. Attached Figure Description

[0024] Figure 1 This is a comparative trend chart of the softening point test data of the low-temperature thermoplastic films prepared in Examples 1-3 and Comparative Examples 1-4 of the present invention.

[0025] Figure 2 This is a comparative trend chart of the tensile strength test data of the low-temperature thermoplastic films prepared in Examples 1-3 and Comparative Examples 1-4 of the present invention. Detailed Implementation

[0026] The present application will be further described in detail below with reference to the embodiments.

[0027] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application are all commercially available.

[0028] Example 1: (a) The preparation method of thiosalicylic acid modified chlorinated paraffin is as follows:

[0029] A1. By weight, add 500 parts of acetone and 50 parts of chlorinated paraffin to the reactor, stir to dissolve, then add 40 parts of thiosalicylic acid and 44 parts of potassium carbonate. React under nitrogen protection at a temperature of 50°C for 12.5 hours to obtain the reactants.

[0030] A2. Extract the reactants obtained in A1 with ethanol, and then dry them under vacuum at 100°C for 2.2 hours to obtain the extract.

[0031] A3. Pour the extract obtained in A2 into tetrahydrofuran, adjust the pH value to 4.1 with hydrochloric acid, then extract in ethanol, and then vacuum dry at 100℃ for 2.2 hours to obtain thiosalicylic acid modified chlorinated paraffin.

[0032] (ii) A method for producing a low-temperature thermoplastic film, comprising the following steps:

[0033] S1. By weight, 100 parts of polyvinyl chloride resin, 12 parts of di-n-octyl phthalate, 3.7 parts of epoxy glyceryl triester, 8.7 parts of stabilizer (specifically 4.8 parts of composite lead salt, 1 part of stearic acid, 1 part of zinc stearate and 1.9 parts of calcium stearate), 1.3 parts of thiosalicylic acid modified chlorinated paraffin and 1.7 parts of ethylene bis-stearamide are mixed to obtain a mixture.

[0034] S2. The mixture obtained in S1 is fed into a twin-screw extruder for extrusion granulation; specifically, the temperature of the twin-screw extruder is raised to 142°C, the mixture obtained in S1 is added to the barrel, the twin-screw extruder is turned on, the mixture is extruded from the outlet, and after passing through a cooling water tank, it is granulated by a pelletizer to obtain granules.

[0035] S3. Put the granules obtained in S2 into the injection molding machine and injection mold them; specifically, spray the release agent onto the mold surface, then raise the temperature of the injection molding machine to 142℃, then add the granules obtained in S2, and injection mold them to obtain a low-temperature thermoplastic film.

[0036] Example 2: The difference between this example and Example 1 is that: a method for producing a low-temperature thermoplastic film includes the following steps:

[0037] S1. By weight, 100 parts of polyvinyl chloride resin, 11.7 parts of di-n-octyl phthalate, 3.5 parts of epoxy glyceryl triester, 8.5 parts of stabilizer (specifically 4.8 parts of composite lead salt, 1 part of stearic acid, 1 part of zinc stearate and 1.7 parts of calcium stearate), 1.2 parts of thiosalicylic acid modified chlorinated paraffin and 1.5 parts of ethylene bis-stearamide are mixed to obtain a mixture.

[0038] S2. The mixture obtained in S1 is fed into a twin-screw extruder for extrusion granulation; specifically, the temperature of the twin-screw extruder is raised to 142°C, the mixture obtained in S1 is added to the barrel, the twin-screw extruder is turned on, the mixture is extruded from the outlet, and after passing through a cooling water tank, it is granulated by a pelletizer to obtain granules.

[0039] S3. Put the granules obtained in S2 into the injection molding machine and injection mold them; specifically, spray the release agent onto the mold surface, then raise the temperature of the injection molding machine to 142℃, then add the granules obtained in S2, and injection mold them to obtain a low-temperature thermoplastic film.

[0040] Example 3: The difference between this example and Example 1 is that: a method for producing a low-temperature thermoplastic film includes the following steps:

[0041] S1. By weight, 100 parts of polyvinyl chloride resin, 12.2 parts of di-n-octyl phthalate, 4 parts of epoxy glyceryl triester, 9 parts of stabilizer (specifically 5 parts of composite lead salt, 1 part of stearic acid, 1 part of zinc stearate and 2 parts of calcium stearate), 1.5 parts of thiosalicylic acid modified chlorinated paraffin and 1.8 parts of ethylene bis-stearamide are mixed to obtain a mixture.

[0042] S2. The mixture obtained in S1 is fed into a twin-screw extruder for extrusion granulation; specifically, the temperature of the twin-screw extruder is raised to 142°C, the mixture obtained in S1 is added to the barrel, the twin-screw extruder is turned on, the mixture is extruded from the outlet, and after passing through a cooling water tank, it is granulated by a pelletizer to obtain granules.

[0043] S3. Put the granules obtained in S2 into the injection molding machine and injection mold them; specifically, spray the release agent onto the mold surface, then raise the temperature of the injection molding machine to 142℃, then add the granules obtained in S2, and injection mold them to obtain a low-temperature thermoplastic film.

[0044] Comparative Example 1: The difference between this comparative example and Example 1 is that the amount of epoxy glyceryl triester added is reduced to 3 parts; and thiosalicylic acid modified chlorinated paraffin and ethylene bis-stearamide are not added.

[0045] Specifically, a method for producing a low-temperature thermoplastic film includes the following steps:

[0046] S1. By weight, 100 parts of polyvinyl chloride resin, 12 parts of di-n-octyl phthalate, 3 parts of epoxy glycerol triester and 8.7 parts of stabilizer (specifically 4.8 parts of composite lead salt, 1 part of stearic acid, 1 part of zinc stearate and 1.9 parts of calcium stearate) are mixed to obtain a mixture.

[0047] S2. The mixture obtained in S1 is fed into a twin-screw extruder for extrusion granulation; specifically, the temperature of the twin-screw extruder is raised to 142°C, the mixture obtained in S1 is added to the barrel, the twin-screw extruder is turned on, the mixture is extruded from the outlet, and after passing through a cooling water tank, it is granulated by a pelletizer to obtain granules.

[0048] S3. Put the granules obtained in S2 into the injection molding machine and injection mold them; specifically, spray the release agent onto the mold surface, then raise the temperature of the injection molding machine to 142℃, then add the granules obtained in S2, and injection mold them to obtain a low-temperature thermoplastic film.

[0049] Comparative Example 2: The difference between this comparative example and Example 1 is that thiosalicylic acid-modified chlorinated paraffin and ethylene bis-stearamide are not added.

[0050] Specifically, a method for producing a low-temperature thermoplastic film includes the following steps:

[0051] S1. By weight, 100 parts of polyvinyl chloride resin, 12 parts of di-n-octyl phthalate, 3.7 parts of epoxy glycerol triester and 8.7 parts of stabilizer (specifically 4.8 parts of composite lead salt, 1 part of stearic acid, 1 part of zinc stearate and 1.9 parts of calcium stearate) are mixed to obtain a mixture.

[0052] S2. The mixture obtained in S1 is fed into a twin-screw extruder for extrusion granulation; specifically, the temperature of the twin-screw extruder is raised to 142°C, the mixture obtained in S1 is added to the barrel, the twin-screw extruder is turned on, the mixture is extruded from the outlet, and after passing through a cooling water tank, it is granulated by a pelletizer to obtain granules.

[0053] S3. Put the granules obtained in S2 into the injection molding machine and injection mold them; specifically, spray the release agent onto the mold surface, then raise the temperature of the injection molding machine to 142℃, then add the granules obtained in S2, and injection mold them to obtain a low-temperature thermoplastic film.

[0054] Comparative Example 3: The difference between this comparative example and Example 1 is that ethylene bis-stearamide is not added.

[0055] Specifically, a method for producing a low-temperature thermoplastic film includes the following steps:

[0056] S1. By weight, 100 parts of polyvinyl chloride resin, 12 parts of di-n-octyl phthalate, 3.7 parts of epoxy glyceryl triester, 8.7 parts of stabilizer (specifically 4.8 parts of composite lead salt, 1 part of stearic acid, 1 part of zinc stearate and 1.9 parts of calcium stearate) and 1.3 parts of thiosalicylic acid modified chlorinated paraffin are mixed to obtain a mixture.

[0057] S2. The mixture obtained in S1 is fed into a twin-screw extruder for extrusion granulation; specifically, the temperature of the twin-screw extruder is raised to 142°C, the mixture obtained in S1 is added to the barrel, the twin-screw extruder is turned on, the mixture is extruded from the outlet, and after passing through a cooling water tank, it is granulated by a pelletizer to obtain granules.

[0058] S3. Put the granules obtained in S2 into the injection molding machine and injection mold them; specifically, spray the release agent onto the mold surface, then raise the temperature of the injection molding machine to 142℃, then add the granules obtained in S2, and injection mold them to obtain a low-temperature thermoplastic film.

[0059] Comparative Example 4: The difference between this comparative example and Example 1 is that no thiosalicylic acid-modified chlorinated paraffin is added.

[0060] Specifically, a method for producing a low-temperature thermoplastic film includes the following steps:

[0061] S1. By weight, 100 parts of polyvinyl chloride resin, 12 parts of di-n-octyl phthalate, 3.7 parts of epoxy glyceryl triester, 8.7 parts of stabilizer (specifically 4.8 parts of composite lead salt, 1 part of stearic acid, 1 part of zinc stearate and 1.9 parts of calcium stearate) and 1.7 parts of ethylene bis-stearamide are mixed to obtain a mixture.

[0062] S2. The mixture obtained in S1 is fed into a twin-screw extruder for extrusion granulation; specifically, the temperature of the twin-screw extruder is raised to 142°C, the mixture obtained in S1 is added to the barrel, the twin-screw extruder is turned on, the mixture is extruded from the outlet, and after passing through a cooling water tank, it is granulated by a pelletizer to obtain granules.

[0063] S3. Put the granules obtained in S2 into the injection molding machine and injection mold them; specifically, spray the release agent onto the mold surface, then raise the temperature of the injection molding machine to 142℃, then add the granules obtained in S2, and injection mold them to obtain a low-temperature thermoplastic film.

[0064] Experimental Example: Test Subjects: Low-temperature thermoplastic films prepared in Examples 1-3 and Comparative Examples 1-4. Test Content: ① Softening Point (Softening Temperature): Under different temperature conditions, the hardness of the material was tested using a Shore hardness tester. Based on the hardness-temperature curve of the material, the start and end temperatures of the sudden change in hardness were determined, thereby analyzing the softening point of the material. ② Tensile Strength: The material was subjected to longitudinal axis tensile loading using an electronic universal testing machine, and the tensile strength properties of the material were analyzed. Test Results: See Table 1.

[0065] Table 1. Experimental Data

[0066] Softening point (°C) Tensile strength (MPa) Example 1 52.2 269.7 Example 2 52.5 269.2 Example 3 52.3 269.0 Comparative Example 1 53.6 266.4 Comparative Example 2 51.7 261.8 Comparative Example 3 52.0 259.2 Comparative Example 4 51.9 267.3

[0067] Results Analysis: Combining the data in Table 1 and... Figures 1-2 Analysis of Examples 1-3 shows that the low-temperature thermoplastic film prepared by the present invention (Examples 1-3) has a softening point as low as below 52.5℃ and a tensile strength as high as above 269.0MPa.

[0068] Combining the data in Table 1 and Figures 1-2Analysis of Example 1 and Comparative Examples 1-4:

[0069] Specifically, comparing Comparative Examples 1 and 2, it can be seen that compared to Comparative Example 1, which added 3 parts of epoxy triglyceride, Comparative Example 2 increased the amount of epoxy triglyceride to 3.7 parts. As a result, the softening point of the low-temperature thermoplastic film decreased from 53.6℃ (Comparative Example 1) to 51.7℃ (Comparative Example 2). However, at the same time, the tensile strength of the low-temperature thermoplastic film decreased from 266.4 MPa (Comparative Example 1) to 261.8 MPa (Comparative Example 2). This indicates that increasing the amount of epoxy triglyceride added from 3 parts to 3.7 parts (i.e., increasing the amount of epoxy triglyceride added) can lower the softening point of the low-temperature thermoplastic film, but at the same time, it will also lead to a decrease in its tensile strength.

[0070] Specifically, comparing Comparative Examples 2 and 3, it can be seen that, compared to Comparative Example 2, the addition of thiosalicylic acid-modified chlorinated paraffin in Comparative Example 3 alone did not significantly change the softening point of the low-temperature thermoplastic film, and the tensile strength decreased from 261.8 MPa (Comparative Example 2) to 259.2 MPa (Comparative Example 3). This indicates that simply adding thiosalicylic acid-modified chlorinated paraffin can actually lead to a decrease in the tensile strength of the low-temperature thermoplastic film.

[0071] This is mainly because, although thiosalicylic acid-modified chlorinated paraffin enhances the interfacial adhesion with polyvinyl chloride resin by introducing carboxyl groups (-COOH) and sulfur-containing groups, the thiosalicylic acid-modified chlorinated paraffin itself is still a rigid particle. In the epoxy glycerol triester system, the plasticizer has significantly weakened the intermolecular forces of polyvinyl chloride resin, causing the rigid particles of thiosalicylic acid-modified chlorinated paraffin to become stress concentration points, which easily triggers microcrack propagation and reduces tensile strength.

[0072] Specifically, comparing Comparative Examples 2 and 4, it can be seen that, compared to Comparative Example 2, the addition of ethylene bis-stearamide alone in Comparative Example 4 did not significantly change the softening point of the low-temperature thermoplastic film, but the tensile strength increased from 261.8 MPa (Comparative Example 2) to 267.3 MPa (Comparative Example 4). This indicates that the addition of ethylene bis-stearamide alone can improve the tensile strength of the prepared low-temperature thermoplastic film.

[0073] In comparison with Example 1, it can be seen that the simultaneous introduction of thiosalicylic acid-modified chlorinated paraffin and ethylene bis-stearamide can produce a synergistic effect, thereby synergistically improving the tensile strength of the prepared low-temperature thermoplastic film.

[0074] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0075] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for producing a low-temperature thermoplastic film, characterized in that, Includes the following steps: S1. By weight, 100 parts of polyvinyl chloride resin, 11.7-12.2 parts of di-n-octyl phthalate, 3.5-4 parts of epoxy glyceryl triester, 8.5-9 parts of stabilizer, 1.2-1.5 parts of thiosalicylic acid modified chlorinated paraffin, and 1.5-1.8 parts of ethylene bis-stearamide are mixed to obtain a mixture. S2. The mixture obtained in S1 is fed into a twin-screw extruder and extruded and granulated to obtain granules; S3. The granules obtained in S2 are put into an injection molding machine and injection molded to obtain the low-temperature thermoplastic film.

2. The method for producing low-temperature thermoplastic film according to claim 1, characterized in that, The preparation method of the thiosalicylic acid modified chlorinated paraffin is as follows: A1. By weight, add 480-510 parts of acetone and 50 parts of chlorinated paraffin to the reactor, stir to dissolve, then add 37-42 parts of thiosalicylic acid and 42-45 parts of potassium carbonate, and react under inert gas protection to obtain the reactants. A2. Extract the reactants obtained in A1 with ethanol, and then dry them under vacuum to obtain the extract. A3. Pour the extract obtained in A2 into tetrahydrofuran, adjust the pH value to 4-4.2, then pour it into ethanol for extraction, and then vacuum dry to obtain the final product.

3. The method for producing low-temperature thermoplastic film according to claim 2, characterized in that, In A1, the reaction temperature is 50±2℃ and the reaction time is 12-13h.

4. The method for producing low-temperature thermoplastic film according to claim 2, characterized in that, For both A2 and A3, the drying temperature is 100±2℃ and the drying time is 2-2.5h.

5. The method for producing low-temperature thermoplastic film according to claim 2, characterized in that, In A3, the pH value is adjusted using hydrochloric acid.

6. The method for producing low-temperature thermoplastic film according to claim 1, characterized in that, In S1, the stabilizer includes a composite lead salt, stearic acid, zinc stearate and calcium stearate, and the mass ratio of the four is (4.5-5):1:1:(1.5-2).

7. The method for producing low-temperature thermoplastic film according to claim 1, characterized in that, In S2, granulation is performed by extrusion at a temperature of 140-145℃.

8. The method for producing low-temperature thermoplastic film according to claim 1, characterized in that, In S3, injection molding is performed at a temperature of 140-145℃.

9. A low-temperature thermoplastic film, characterized in that, It is produced by the production method described in any one of claims 1 to 8.

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