A thermoreversible gel carrier and its preparation method and application

Abstract

The present invention provides a thermoreversible gel carrier, its preparation method, and application. The thermoreversible gel carrier comprises the following components, by weight: 1-5 parts K-carrageenan, 0.5-2 parts locust bean gum, 0.5-3 parts agar, and 100 parts water. The thermoreversible gel carrier exhibits suitable gel strength, low water extraction rate, and low melting point. It can be used as a mold for preparing products with complex cavity shapes and is easily separable.

Description

Technical Field

[0001] The invention belongs to the technical field of functional gels, and in particular relates to a thermoreversible gel carrier and a preparation method and application thereof. Background Art

[0002] The manufacture of medical devices such as balloon catheters, thin-walled envelopes, and tissue expanders can be done by dip coating, electrospinning, or spraying. These methods require the preparation of a dip-coated, electrospinned, or sprayed carrier first. That is, the carrier is used as a mold, and thin-walled products such as balloon catheters, thin-walled envelopes, and tissue expanders are formed on the surface of the carrier by dip coating, electrospinning, or spraying. Then, the carrier needs to be removed. Products with cavities can be prepared by removing the carrier after forming by dip coating, electrospinning, or spraying. However, the process design and carrier selection must be based on the material properties of the product during preparation. The separation of the product and the carrier after forming must be considered to avoid tearing or twisting the cavity during the preparation process, which would damage the product quality. Currently, carriers are usually made of metal, engineering plastics, or ceramics. However, when using materials with poor elasticity to prepare products with cavities, especially products with complex cavity shapes, carriers made of metal, engineering plastics, or ceramics cannot effectively separate the carrier and the product.

[0003] Thermoreversible materials such as carrageenan, gelatin, carboxymethyl cellulose, and sugars (such as glucose, fructose, sucrose, or maltose) have the characteristics of high-temperature dissolution and low-temperature solidification and do not react with organic solvents. However, these materials still have defects in practical applications, such as long solidification time and low molding efficiency; the formed carrier is soft, has poor elasticity, and insufficient mechanical properties; a high perfusion temperature needs to be maintained to ensure fluidity; the concentration required to form a gel is high, and the cost burden is high.

[0004] Therefore, it is necessary to develop a thermoreversible gel carrier with high molding efficiency, good mechanical properties, and easy separation from the product. Summary of the Invention

[0005] In response to the shortcomings of the prior art, the present invention provides a thermoreversible gel carrier, a preparation method, and applications thereof. The thermoreversible gel carrier exhibits suitable gel strength, excellent mechanical properties, low water extraction rate, and a low melting point. It can be used as a mold for preparing products with complex cavity shapes and is easily separable. The preparation method also boasts high molding efficiency.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a thermoreversible gel carrier, comprising the following components in parts by weight: 1 to 5 parts (e.g., 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, or 4.5 parts) of K-carrageenan, 0.5 to 2 parts (e.g., 0.7 parts, 0.9 parts, 1.1 parts, 1.3 parts, 1.5 parts, 1.7 parts, or 1.9 parts), 0.5 to 3 parts (e.g., 0.8 parts, 1.1 parts, 1.4 parts, 1.7 parts, 2.0 parts, 2.3 parts, 2.6 parts, or 2.9 parts), and 100 parts of water.

[0008] In the present invention, a thermoreversible gel carrier is prepared by compounding K-carrageenan, locust bean gum, agar and water. The thermoreversible gel carrier has suitable gel strength and good toughness, low concentration required for gel formation, low melting temperature, and is easy to separate from products with complex cavity shapes. It can be used as a carrier for processes such as dipping, electrospinning or spraying, and as a mold for preparing products with cavities. Among carrageenans, λ-carrageenan does not have gel properties, and the gel formed by l-carrageenan is soft, low in strength, and has poor effect, and cannot meet the performance requirements for preparing product molds. Compared with λ-carrageenan and l-carrageenan, K-carrageenan has a high gel temperature, fast gel speed, high gel strength, and better performance. However, the gel prepared by using only K-carrageenan has strong water extraction properties, and the gel structure is easy to collapse after molding, which cannot meet the requirements. Compounding it with locust bean gum and agar can significantly reduce water extraction and improve gel strength. Compared with locust bean gum, colloids such as gellan gum, xanthan gum or amidated low-ester pectin can suppress the water extraction problem of K-carrageenan, but will cause problems such as being too soft or generating bubbles. The double helix structure of the K-carrageenan and the side chain-free region of the locust bean gum can form a strong bond, so that the micelles are tightly wound and linked, and the generated thermoreversible gel carrier has a higher gel strength. The compounding of K-carrageenan and locust bean gum can not only improve elasticity and toughness, enhance cohesion, but also reduce the water extraction rate, showing a good synergistic effect. The perfusion glue formed by the K-carrageenan, locust bean gum, agar and water is injected into the mold, and after cooling to room temperature, the thermoreversible gel carrier is obtained and can be used without waiting or other post-processing. The preparation is simple and the molding efficiency is high.

[0009] In the present invention, the weight portion of locust bean gum is 0.5-2 parts. As the use and amount of locust bean gum increase, the water separation rate gradually decreases. Considering the requirements of gel strength and gel temperature, the weight portion of locust bean gum is further preferably 1-2 parts.

[0010] Preferably, the mass ratio of the locust bean gum to K-carrageenan is 1:(1-5), for example, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4 or 1:4.5.

[0011] In the present invention, the mass ratio of locust bean gum to K-carrageenan is preferably 1: (1-5). A mass ratio of locust bean gum to K-carrageenan that is too large or too small will affect the gel strength, and a high mass ratio of locust bean gum will cause the perfusion gel to be viscous and difficult to perfuse; a low mass ratio will have a poor effect on inhibiting the water precipitation of K-carrageenan.

[0012] Preferably, the weight portion of the agar is 1 to 3 parts.

[0013] Preferably, the gel strength of the thermoreversible gel carrier is 400-2000 g / cm 2 , for example 500 g / cm 2 , 700g / cm 2 , 900 g / cm 2 、1100 g / cm 2 、1300 g / cm 2 , 1500 g / cm 2 、1700 g / cm 2 or 1900 g / cm 2 etc., more preferably 500~1500 g / cm 2 .

[0014] It should be noted that the gel strength of the thermoreversible gel carrier is preferably 400~2000g / cm 2 If the gel strength is too low, the thermoreversible gel carrier will not be easily suspended on the dip-coating rod. If the gel strength is too high, the thermoreversible gel carrier will be hard and have poor elasticity, making it fragile during demolding. Those skilled in the art can determine the desired gel strength of the thermoreversible gel carrier based on the specific shape and size of the cavity of the product being manufactured.

[0015] Preferably, the melting temperature of the thermoreversible gel carrier is ≤90°C, such as 76°C, 78°C, 80°C, 82°C, 84°C, 86°C or 88°C.

[0016] In the present invention, the melting temperature of the thermoreversible gel carrier is preferably ≤90°C. Too high a melting temperature will prolong the demolding process and cause dislocation, stretching and breakage of the polymer material molecular chains in the product with a cavity, significantly affecting its physical and chemical properties.

[0017] Preferably, the water separation rate of the thermoreversible gel carrier after 2 hours is ≤7%, for example, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6% or 6.5%, etc., more preferably ≤5%.

[0018] In the present invention, water extraction refers to the phenomenon of water seeping from the surface of the thermoreversible gel carrier. If the water extraction rate of the thermoreversible gel carrier is too high, it will make it difficult for the dipping liquid to adhere to the surface of the thermoreversible gel carrier, and the coating film of the obtained product with a cavity will be separated from the thermoreversible gel carrier. In addition, a large amount of water extraction from the thermoreversible gel carrier will also cause structural collapse and shape deformation, resulting in dip coating failure or unsatisfactory results.

[0019] In a second aspect, the present invention provides a method for preparing the thermoreversible gel carrier according to the first aspect, the preparation method comprising the following steps:

[0020] (1) Mix K-carrageenan, locust bean gum, agar and water, heat and stir until the solution boils, and cool to the infusion temperature to obtain the infusion gel solution;

[0021] (2) The perfusion glue prepared in step (1) is injected into a mold and cooled to obtain the thermoreversible gel carrier.

[0022] Preferably, the mixing in step (1) includes any one of stirring mixing, centrifugal mixing or oscillating mixing.

[0023] Preferably, the rotation speed of the heating and stirring in step (1) is 200-500 rpm (for example, 230 rpm, 260 rpm, 290 rpm, 310 rpm, 340 rpm, 370 rpm, 400 rpm, 430 rpm, 460 rpm or 490 rpm, etc.).

[0024] In the present invention, K-carrageenan, locust bean gum and agar are further dissolved and hydrated by heating and stirring, and are fully mixed.

[0025] It should be noted that the heating and stirring described in the present invention can be performed by any conventional heating and stirring method in the art, such as using a constant temperature magnetic stirrer or an overhead powerful electronic stirrer for heating and stirring.

[0026] Preferably, step (1) further includes a preheating step before the heating and stirring.

[0027] Preferably, the preheating temperature is 70-85°C (for example, 72°C, 74°C, 76°C, 78°C, 80°C, 82°C or 84°C), and the preheating time is 10-40 min (for example, 13 min, 16 min, 19 min, 22 min, 25 min, 28 min, 31 min, 34 min or 37 min, etc.), more preferably 10-20 min.

[0028] In the present invention, the preheating temperature is preferably 70-85°C, and the preheating time is preferably 10-20 minutes, which can dissolve K-carrageenan and locust bean gum. The preheating temperature and time will affect the heating time of the preparation process of the thermoreversible gel carrier, thereby affecting the degree of dissolution and hydration of each component of the preparation raw materials, and slightly affecting the melting temperature of the final thermoreversible gel carrier. Short preheating time results in insufficient hydration and reduced strength, while long preheating time has no significant effect, but low efficiency. The preheating can improve the preparation efficiency of the thermoreversible gel carrier and allow each component of the preparation raw materials to fully absorb water and expand. If preheating is not performed, the preparation process is time-consuming, the dissolution or swelling effect is poor, and the gel properties are affected.

[0029] It should be noted that the preheating described in the present invention can be carried out by any conventional heating method in the art, such as water bath heating, oil bath heating or electric furnace heating.

[0030] In the present invention, the K-carrageenan is insoluble in cold water and only swells slowly in cold water, and begins to dissolve when the temperature is ≥70°C; locust bean gum only partially dissolves in cold water and needs to be heated to 85°C and maintained for more than 10 minutes to completely dissolve; agar begins to dissolve at 95°C, and by heating and stirring the solution until it boils, all of the K-carrageenan, locust bean gum, and agar can be completely dissolved, thereby enhancing the gel performance.

[0031] In the present invention, the cold water refers to water with a temperature of ≤40°C (eg, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C or 35°C, etc.).

[0032] Preferably, the perfusion temperature is 50-100°C (eg, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, or 95°C), more preferably 55-80°C.

[0033] In the present invention, the pouring temperature is preferably 50-100° C., and the formed pouring glue has good fluidity and is suitable for narrow mold flow channels without the need for additional pressurizing equipment.

[0034] It should be noted that the selection of the pouring temperature can be determined by those skilled in the art based on the shape, size, and complexity of the mold structure, taking into account the actual situation. Furthermore, while higher pouring temperatures improve fluidity, the higher the pouring temperature, the greater the volume shrinkage of the thermoreversible gel carrier formed after cooling. Excessively high pouring temperatures not only prolong the cooling wait time but also significantly shrink the volume of the formed thermoreversible gel carrier, affecting the desired shape.

[0035] For convenience, the preferred filling tool for injecting the glue solution into the mold is a syringe. Alternatively, a glue dispensing machine or a glue dispenser can be used. Those skilled in the art will appreciate the choice based on practical needs. To maintain a clean surface for the thermoreversible gel carrier, the preparation of the thermoreversible gel carrier can be performed while wearing smooth, powder-free gloves.

[0036] Preferably, the cooling in step (2) includes any one of cooling by immersion in a cooling medium, air cooling or natural cooling, and more preferably cooling by immersion in a cooling medium.

[0037] In the present invention, the cooling in step (2) can make the gel network structure of the thermoreversible gel carrier more orderly and uniform, improve the gel strength of the thermoreversible gel carrier, and accelerate the molding rate. Cooling by immersion in a cooling medium can provide a freer and more relaxed environment for the movement of macromolecules, prevent gel dehydration and shrinkage, and construct a solid gel network structure. Compared with cooling by immersion in a cooling medium, air cooling is more likely to cause water loss, affecting the shape of the thermoreversible gel carrier; and natural cooling is slow.

[0038] Preferably, the cooling medium comprises water.

[0039] Preferably, the temperature of the cooling medium is 4-35°C (eg, 5°C, 10°C, 15°C, 20°C, 25°C, or 30°C), more preferably 20-25°C.

[0040] Preferably, the cooling time during immersion in the cooling medium is 2 to 8 minutes, for example, 3 minutes, 4 minutes, 5 minutes, 6 minutes or 7 minutes.

[0041] In a third aspect, the present invention provides a use of the thermoreversible gel carrier as described in the first aspect in the manufacture of a product having a cavity.

[0042] Preferably, the product having a cavity includes a product with a complex cavity shape.

[0043] Illustratively, the product with a complex cavity shape includes a product with a convex or irregularly shaped cavity, such as a heart-shaped balloon or a product with a gourd-shaped cavity.

[0044] Preferably, the manufacturing process of the product having the cavity includes any one of dip coating, electrospinning or spray coating.

[0045] The present invention utilizes the characteristic that a thermoreversible gel carrier can achieve reverse phase transition within a certain temperature range, and uses it as a carrier for dip coating, electrospinning or spraying processes, and as a mold for preparing products with a cavity. The gel molding efficiency is high, it does not react with organic solvents, and the operation is simple.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] In the present invention, the thermoreversible gel carrier is prepared by compounding K-carrageenan, locust bean gum, agar and water. The thermoreversible gel carrier has high molding efficiency, suitable gel strength, low water separation rate, low concentration required for gel formation, low perfusion temperature, good surface adsorption capacity for dipping liquid, can be used as a mold for preparing products with cavities, has a low melting temperature, is easy to separate from products with cavities, and can easily separate even products with complex cavity shapes, thereby ensuring the integrity of products with cavities. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 A structural diagram of the thermoreversible gel carrier provided in Example 1;

[0049] Figure 2 Structural diagram of the balloon provided for Application Example 1. DETAILED DESCRIPTION

[0050] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0051] The sources of some components in the Examples and Comparative Examples are as follows:

[0052] K-carrageenan: CAS No. 9000-07-1, Adamas Life Sciences, a subsidiary of Titan Technologies;

[0053] l-Carrageenan: CAS No. 9062-07-1, Adamas Life Sciences, a subsidiary of Titan Technologies;

[0054] Locust bean gum: CAS number 9000-40-2, manufacturer Aladdin;

[0055] Agar: CAS No. 9002-18-0, Adamas Life Sciences, a subsidiary of Titan Technologies;

[0056] Low melting point agarose: CAS number 9012-36-6, manufacturer: Maclean.

[0057] Example 1

[0058] This embodiment provides a thermoreversible gel carrier and a preparation method thereof. The preparation method of the thermoreversible gel carrier is as follows:

[0059] (1) Add 100 parts by weight of deionized water to a beaker and stir. Then slowly add 3 parts by weight of K-carrageenan, 1 part by weight of locust bean gum, and 1 part by weight of agar in sequence. Stir at room temperature (25°C) to avoid agglomeration. Then heat to 82°C for 15 min. After preheating, heat and stir until the solution boils at a stirring speed of 250 rpm. Then cool to 75°C in a water bath to obtain the injection glue solution.

[0060] (2) Use a 50mL syringe to inject the perfusion glue prepared in step (1) into the mold, insert a stainless steel dip-coating rod into the perfusion glue while it is hot, and then immerse it in deionized water at 25°C for cooling for 5 minutes. Allow the perfusion glue to cool and set, take it out and hang it in a clean area to obtain the thermoreversible gel carrier, as shown in FIG. Figure 1 shown.

[0061] Example 2

[0062] This embodiment provides a thermoreversible gel carrier and a preparation method thereof. The only difference between this embodiment and Example 1 is that the weight portion of K-carrageenan is adjusted to 1 part, and other conditions are the same as those in Example 1.

[0063] Example 3

[0064] This embodiment provides a thermoreversible gel carrier and a preparation method thereof. The only difference between this embodiment and Example 1 is that the weight portion of K-carrageenan is adjusted to 5 parts, and other conditions are the same as those in Example 1.

[0065] Example 4

[0066] This embodiment provides a thermoreversible gel carrier and a preparation method thereof. The only difference between this embodiment and Example 1 is that the weight portion of locust bean gum is adjusted to 0.5 parts, and other conditions are the same as those in Example 1.

[0067] Example 5

[0068] This embodiment provides a thermoreversible gel carrier and a preparation method thereof. The only difference between this embodiment and Example 1 is that the weight portion of locust bean gum is adjusted to 2 parts, and other conditions are the same as those in Example 1.

[0069] Example 6

[0070] This embodiment provides a thermoreversible gel carrier and a preparation method thereof. The only difference between this embodiment and Example 1 is that the weight portion of agar is adjusted to 0.5 parts, and other conditions are the same as those in Example 1.

[0071] Example 7

[0072] This embodiment provides a thermoreversible gel carrier and a preparation method thereof. The only difference between this embodiment and Example 1 is that the weight portion of agar is adjusted to 2 parts, and other conditions are the same as those in Example 1.

[0073] Example 8

[0074] This embodiment provides a thermoreversible gel carrier and a preparation method thereof. The difference between this embodiment and embodiment 1 is that the preheating temperature in step (1) is adjusted to 60° C., and other conditions are the same as those in embodiment 1.

[0075] Example 9

[0076] This embodiment provides a thermoreversible gel carrier and a preparation method thereof. The difference between this embodiment and embodiment 1 is that the preheating temperature in step (1) is adjusted to 70° C., and other conditions are the same as those in embodiment 1.

[0077] Example 10

[0078] This embodiment provides a thermoreversible gel carrier and a preparation method thereof. The difference between this embodiment and embodiment 1 is that the preheating temperature in step (1) is adjusted to 85° C., and other conditions are the same as those in embodiment 1.

[0079] Example 11

[0080] This embodiment provides a thermoreversible gel carrier and a preparation method thereof. The difference between this embodiment and embodiment 1 is that the preheating temperature in step (1) is adjusted to 90° C., and other conditions are the same as those in embodiment 1.

[0081] Example 12

[0082] This embodiment provides a thermoreversible gel carrier and a preparation method thereof. The difference between this embodiment and embodiment 1 is that step (1) does not include a preheating step, and other conditions are the same as those in embodiment 1.

[0083] Example 13

[0084] This embodiment provides a thermoreversible gel carrier and a preparation method thereof. The only difference between this embodiment and embodiment 6 is that the cooling method in step (2) is adjusted to natural cooling at room temperature of 25°C. Other conditions are the same as those in embodiment 6.

[0085] Example 14

[0086] This embodiment provides a thermoreversible gel carrier and a preparation method thereof. The only difference between this embodiment and embodiment 1 is that the cooling method in step (2) is adjusted to natural cooling at room temperature of 25°C. Other conditions are the same as those in embodiment 1.

[0087] Example 15

[0088] This embodiment provides a thermoreversible gel carrier and a preparation method thereof. The only difference between this embodiment and embodiment 7 is that the cooling method in step (2) is adjusted to natural cooling at room temperature of 25°C. Other conditions are the same as those in embodiment 7.

[0089] Comparative Example 1

[0090] This comparative example provides a thermoreversible gel carrier and a preparation method thereof, which differs from Example 1 only in that K-carrageenan is replaced with l-carrageenan of the same mass, and other conditions are the same as those in Example 1.

[0091] Comparative Example 2

[0092] This comparative example provides a thermoreversible gel carrier and a preparation method thereof, which differs from Example 1 only in that K-carrageenan and locust bean gum are not added, the weight portion of agar is adjusted to 5 parts, and other conditions are the same as Example 1.

[0093] Comparative Example 3

[0094] This comparative example provides a thermoreversible gel carrier and a preparation method thereof, which differs from Example 1 only in that agar is not added, the weight portion of K-carrageenan is adjusted to 4 parts, and other conditions are the same as Example 1.

[0095] Comparative Example 4

[0096] This comparative example provides a thermoreversible gel carrier and a preparation method thereof. The only difference between the comparative example and Example 1 is that 3 parts by weight of K-carrageenan, 1 part by weight of locust bean gum, and 1 part by weight of agar are replaced with 5 parts by weight of low-melting-point agarose. Other conditions are the same as those in Example 1.

[0097] Comparative Example 5

[0098] This comparative example provides a thermoreversible gel carrier and a preparation method thereof, which differs from Example 1 only in that locust bean gum is not added, and other conditions are the same as those in Example 1.

[0099] Application Example 1

[0100] This application example provides a balloon, which is prepared by the following method:

[0101] The thermoreversible gel carrier provided in Example 1 was immersed in the dipping solution for dipping, taken out, dried, and immersed in the dipping solution again for dipping. The dipping was repeated 4 times. After the balloon shell layer was formed by the dipping process, demolding was performed, that is, the thermoreversible gel carrier with the balloon shell layer was placed in water and heated to 70°C. The stainless steel dipping rod was removed to generate a balloon hole. The melted liquid of the thermoreversible gel carrier was gently squeezed to discharge the melted liquid of the thermoreversible gel carrier from the balloon hole. Finally, 85°C hot water was drawn with a syringe to repeatedly rinse the inside of the balloon shell 5 times to completely remove the residual thermoreversible gel to obtain the balloon. The balloon was a heart-shaped balloon, as shown in FIG. Figure 2 shown.

[0102] The dipping solution is a mixture of dichloromethane and PLCL, and the concentration of PLCL in the dipping solution is 15% (w / v).

[0103] Application Examples 2~15

[0104] Application Examples 2 to 15 provide a balloon, which differs from Application Example 1 only in that the thermoreversible gel carriers provided in Examples 2 to 15 are used to replace the thermoreversible gel carrier provided in Example 1, and other conditions are the same as those in Application Example 1.

[0105] Comparative Application Examples 1 to 5

[0106] Comparative Application Examples 1 to 5 provide a balloon, which differs from Application Example 1 only in that the thermoreversible gel carrier provided in Example 1 is replaced by the thermoreversible gel carrier provided in Comparative Examples 1 to 5, and other conditions are the same as those in Application Example 1.

[0107] Performance Testing

[0108] The perfusion gel solutions provided in Examples 1 to 12 and Comparative Examples 1 to 4 were treated as follows to test the gelation temperature and the melting temperature of the thermoreversible gel carrier.

[0109] (1) Gel temperature: Pour 10 mL of the perfusion glue into a test tube, insert a temperature probe so that its temperature sensing element is below the liquid surface, and place the test tube containing the perfusion glue in a water bath to cool it down. The water level should be at least 2 cm above the top of the perfusion glue. The initial temperature of the water bath is 60 °C. Place it in a 25 °C environment and let it cool down naturally until the test tube is tilted at a 90° angle and the perfusion glue does not flow. This is the solidification temperature.

[0110] (2) Melting temperature: Pour 10 mL of the perfusion gel into a test tube with an inner diameter of 16 mm. Immerse the part of the test tube containing the perfusion gel in deionized water at 25°C and cool it for 5 minutes. The water level should be at least 2 cm above the top of the perfusion gel to quickly reduce the overall temperature. This will prepare a thermoreversible gel carrier. Place a small steel ball with a diameter of 8 mm on the thermoreversible gel carrier. Place the test tube at room temperature for 2 hours, then heat it in a 30°C water bath for 10 minutes. Then increase the temperature at a rate of 1°C per minute. When the small steel ball falls to the bottom of the test tube, the temperature at this time is the melting temperature.

[0111] The perfusion gel solutions provided in Examples 1 to 15 and Comparative Examples 1 to 4 were treated as follows to test the gel strength of the thermoreversible gel carrier.

[0112] A 90 mm diameter Petri dish was filled with the perfusion gel, which was cooled to prepare a thermoreversible gel carrier. The test was then placed at room temperature (25°C) for 2 hours. The test was performed using an Instron 34 TM-5 tensile testing machine mold, a stainless steel cylindrical probe with a diameter of 10 mm, a pre-test speed of 1.50 mm / s, a trigger force of 10 g, and a test speed of 1.00 mm / s. The maximum force measured when the probe entered the thermoreversible gel carrier to a depth of 4 mm was used to calculate the gel strength of the sample. The test was repeated three times, with the test points spaced >2 cm apart, and the results were averaged.

[0113] During the tests of Examples 1-12 and Comparative Examples 1-4, the cooling step was to immerse the portion of the test tube containing the grouting solution in deionized water at 25°C for 5 minutes, with the water level at least 2 cm above the top of the grouting solution, so that the overall temperature dropped rapidly.

[0114] During the testing of Examples 13-15, the cooling was performed naturally at room temperature of 25°C.

[0115] The perfusion gel solutions provided in Example 1, Example 4 and Comparative Example 5 were treated as follows to test the water extraction rate of the thermoreversible gel carrier.

[0116] A cylindrical mold with an inner diameter of 3.1 cm and a height of 2.9 cm was filled with the potting glue. The mold was then immersed in 25°C deionized water and cooled for 5 minutes. The water level was at least 2 cm above the top of the potting glue to rapidly reduce the overall temperature, thereby preparing a thermoreversible gel carrier. A water leaching rate test was then conducted. The test environment was maintained at 25°C ± 2 and a relative humidity of 50% ± 5%. The prepared thermoreversible gel carrier was weighed and recorded as the initial mass m1 (g). After a period of time, the sample was gently squeezed with a paper towel to remove moisture and weighed again. The mass was recorded as m2 (g). The water leaching rate was calculated according to the following formula:

[0117] Water separation rate (%) = [(m1-m2) / m1] × 100%;

[0118] The water extraction rates after 1 hour and 2 hours of storage were tested respectively. The smaller the water extraction rate, the better the water holding capacity of the thermoreversible gel carrier.

[0119] The test results are shown in Tables 1 and 2 below:

[0120] Table 1

[0121]

[0122] In Table 1, “ / ” means that the test was not performed.

[0123] Table 2

[0124]

[0125] In the present invention, the thermoreversible gel carrier prepared in Example 1 (such as Figure 1 ) as a mold, a balloon with the same cavity shape as the thermoreversible gel carrier can be prepared (e.g. Figure 2 ).

[0126] From the test results in Table 1, it can be seen from the comparison of Examples 1 to 3 that with the increase of K-carrageenan content, the gelation temperature of the thermoreversible gel carrier gradually increases and the gel strength also gradually increases. The K-carrageenan content can be selected to match the gelation temperature requirements.

[0127] Comparison of Examples 1, 4, and 5 shows that the gel strength decreases gradually with the increase of locust bean gum.

[0128] Comparison of Examples 1, 6, and 7 shows that the gel strength gradually increases with the increase of agar, but the melting temperature increases. The gel strength can be adjusted by adjusting the amount of agar.

[0129] From the comparison of Examples 1 and 8 to 11, it can be seen that with the increase of preheating temperature, the gel strength first increases and then decreases, but the range of change of gel strength is not large, and the gel strength can be adjusted more accurately by the preheating temperature.

[0130] Comparison between Examples 1 and 12 shows that without preheating, the gel strength of the obtained thermoreversible gel carrier will be adversely affected to a certain extent.

[0131] A comparison between Example 6 and Example 13, a comparison between Example 1 and Example 14, and a comparison between Example 7 and Example 15 shows that natural cooling and cooling by immersion in water have little effect on the gel strength. The gel strength of the thermoreversible gel carrier prepared by natural cooling is slightly improved, but cooling by immersion in water can accelerate the cooling and shaping of the thermoreversible gel carrier and improve efficiency.

[0132] Compared with Example 1, it can be seen that when K-carrageenan is replaced with l-carrageenan of the same mass (Comparative Example 1), the gel strength is greatly reduced. Therefore, it can be seen that the thermoreversible gel carrier prepared by compounding K-carrageenan with locust bean gum and agar in the present invention has better gel strength performance.

[0133] Comparison between Example 1 and Comparative Example 2 shows that the thermoreversible gel carrier prepared by compounding K-carrageenan, locust bean gum and agar in the present invention has a higher gel temperature, a lower melting temperature and a more suitable gel strength.

[0134] Compared with Example 1, it can be seen that if the thermoreversible gel carrier prepared without adding agar (Comparative Example 3) has too low gel strength, the gel strength is too low, and it will deform when hung on the dipping rod, and may even be punctured or broken when hung, which cannot meet the use requirements.

[0135] Comparison between Example 1 and Comparative Example 4 shows that the thermoreversible gel carrier prepared using low-melting-point agarose in Comparative Example 4 exhibits excessively high gel strength and poor elasticity. Furthermore, the wall thickness of the balloon prepared using this carrier (Application Example 4) is only 86.5 μm, significantly lower than the 132.6 μm wall thickness of the balloon prepared using the thermoreversible gel carrier provided in Example 1 (Application Example 1), resulting in low adsorption capacity for the dipping solution. The wall thickness of the balloons prepared in Application Examples 2 to 15 is similar to that of Application Example 1. This demonstrates that the thermoreversible gel carrier prepared by compounding K-carrageenan, locust bean gum, and agar in the present invention exhibits high gelation temperature, suitable gel strength, and good adsorption capacity for the dipping solution.

[0136] As shown in Table 2, compared with Example 1, the absence of locust bean gum (Comparative Example 5) results in a higher water extraction rate for the resulting thermoreversible gel carrier. A comparison of Comparative Example 5 with Examples 1 and 4 shows that the water extraction rate decreases with the addition and amount of locust bean gum.

[0137] It can be seen from Application Examples 1-15 that by utilizing the characteristic that the thermoreversible gel carrier can realize reverse phase transition within a certain temperature range, it can be used as a carrier for the dip coating process and for preparing molds for products with cavities. It has the characteristics of high gel molding efficiency, no reaction with organic solvents, easy separation from the product, and simple operation.

[0138] In summary, the thermoreversible gel carrier prepared by compounding K-carrageenan, locust bean gum, agar and water in the present invention has high molding efficiency, appropriate gel strength, low water extraction rate, low concentration required for gel formation, high gel temperature, good surface adsorption capacity for dipping liquid, can be used as a mold for preparing products with a cavity, has a low melting temperature, and is easy to separate from the product with a cavity.

[0139] The applicant states that while the above-described embodiments illustrate the process of the present invention, the present invention is not limited to the above-described process steps, nor does it imply that the present invention must rely on the above-described process steps for implementation. Those skilled in the art will appreciate that any improvements to the present invention, equivalent substitutions for the raw materials used, additions of auxiliary components, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A thermoreversible gel carrier, characterized in that: The thermoreversible gel carrier comprises the following components by weight: 1-5 parts of K-carrageenan, 0.5-2 parts of locust bean gum, 0.5-3 parts of agar, and 100 parts of water. After the product having the cavity is formed, the thermoreversible gel carrier can be easily separated from the product by melting to avoid physical damage to the product. The water extraction rate of the thermoreversible gel carrier after being left for 2 hours is ≤7%. The mass ratio of the locust bean gum to K-carrageenan is 1:(1-5); The thermoreversible gel carrier is prepared by the following method: (1) K-carrageenan, locust bean gum, agar, and water are mixed, heated and stirred until the solution boils, and cooled to the perfusion temperature to obtain a perfusion gel; (2) injecting the perfusion glue obtained in step (1) into a mold and cooling it to obtain the thermoreversible gel carrier; The gel strength of the thermoreversible gel carrier is 400 to 2000 g / cm 2 ; The melting temperature of the thermoreversible gel carrier is ≤90°C.

2. A method for preparing the thermoreversible gel carrier according to claim 1, characterized in that: The preparation method comprises the following steps: (1) K-carrageenan, locust bean gum, agar, and water are mixed, heated and stirred until the solution boils, and cooled to the perfusion temperature to obtain a perfusion gel; (2) injecting the perfusion glue obtained in step (1) into a mold and cooling it to obtain the thermoreversible gel carrier.

3. The preparation method according to claim 2, characterized in that The mixing in step (1) includes any one of stirring mixing, centrifugal mixing or oscillating mixing; The rotation speed of the heating and stirring in step (1) is 200 to 500 rpm.

4. The preparation method according to claim 2, characterized in that The step (1) further includes a preheating step before the heating and stirring; The preheating temperature is 70-85° C., and the preheating time is 10-40 minutes.

5. The preparation method according to claim 2, characterized in that The perfusion temperature is 50-100°C.

6. The preparation method according to claim 2, characterized in that The cooling in step (2) includes cooling by immersion in a cooling medium, air cooling or natural cooling.

7. The preparation method according to claim 6, characterized in that The cooling medium includes water; The temperature of the cooling medium is 4 to 35°C; The cooling time by immersing in the cooling medium is 2 to 8 minutes.

8. Use of the thermoreversible gel carrier according to claim 1 in the manufacture of products with a cavity.

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