Thermal reversible gel carrier as well as preparation method and application thereof

Abstract

The invention provides a thermal reversible gel carrier as well as a preparation method and application thereof. The thermal reversible gel carrier is prepared from the following components in parts by weight: 1 to 5 parts of K-carrageenan, 0.5 to 2 parts of locust bean gum, 0.5 to 3 parts of agar and 100 parts of water. The thermal reversible gel carrier disclosed by the invention is proper in gel strength, low in bleeding rate and low in melting temperature, can be used as a mold for preparing a product with a complicated cavity shape, and is easy to separate.

Description

Technical Field

[0001] The invention belongs to the technical field of functional gels, and in particular relates to a thermally reversible 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 manufactured by dip-coating, electrospinning, or spraying. These methods require the preparation of dip-coating, electrospinning, or spraying carriers, 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, and then the carrier needs to be removed. The method of removing the carrier after forming by dip-coating, electrospinning, or spraying can prepare products with cavities, but the process design and carrier selection must be carried out according to the material properties of the product during preparation, and the separation of the product and the carrier after molding must be considered to avoid tearing or twisting the cavity during the preparation process, resulting in damage to the product quality. At present, the carrier is usually made of metal, engineering plastics, or ceramics, but when using materials with poor elasticity to prepare products with cavities, especially products with complex cavity shapes, the carrier made of metal, engineering plastics, or ceramics cannot effectively achieve the separation of the carrier and the product.

[0003] Thermoreversible materials such as carrageenan, gelatin, carboxymethyl cellulose, sugar substances (such as glucose, fructose, sucrose or maltose), etc., have the characteristics of high temperature dissolution, low temperature solidification, and no reaction 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, with 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 view of the shortcomings of the prior art, the present invention aims to provide a thermoreversible gel carrier and a preparation method and application thereof. The thermoreversible gel carrier has suitable gel strength, good mechanical properties, low water separation rate, and low melting temperature, can be used as a mold for preparing products with complex cavity shapes and is easy to separate, and the preparation method has 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, 2, 2.5, 3, 3.5, 4 or 4.5 parts) of K-carrageenan, 0.5 to 2 parts (e.g., 0.7, 0.9, 1.1, 1.3, 1.5, 1.7 or 1.9 parts) of locust bean gum, 0.5 to 3 parts (e.g., 0.8, 1.1, 1.4, 1.7, 2.0, 2.3, 2.6 or 2.9 parts) of agar, 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, 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 effects, and cannot meet the performance requirements of a mold for preparing products. Compared with λ-carrageenan and l-carrageenan, K-carrageenan has a high gel temperature, a fast gel speed, a high gel strength, and better performance. However, the gel made of only K-carrageenan has strong water separation, and the gel structure is easy to collapse after molding, which cannot meet the needs. Its compounding with locust bean gum and agar can significantly reduce water separation and improve gel strength. Compared with locust bean gum, colloids such as gellan gum, xanthan gum or amidated low-ester pectin can inhibit the water precipitation 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 precipitation 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 can be used without waiting or other post-processing, and the preparation is simple and the molding efficiency is high.

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

[0011] In the present invention, the mass ratio of locust bean gum to K-carrageenan is preferably 1: (1-5). Too large or too small a mass ratio of locust bean gum to K-carrageenan 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 proportion of the agar is 1 to 3 parts.

[0013] Preferably, the gel strength of the thermoreversible gel carrier is 400-2000 g / cm 2 , e.g. 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 to 1500 g / cm 2 .

[0014] It should be noted that the gel strength of the thermoreversible gel carrier is preferably 400-2000 g / cm 2 If the gel strength is too low, the thermoreversible gel carrier is not easy to be suspended on the dip coating rod; if the gel strength is too high, the thermoreversible gel carrier is hard and has poor elasticity, and is easily broken when demolded. Those skilled in the art can determine the gel strength of the thermoreversible gel carrier to be selected according to the specific shape and size of the cavity of the product to be prepared.

[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 demoulding process and cause dislocation, stretching and breakage of the polymer material molecular chains in the product with the cavity, significantly affecting its physical and chemical properties.

[0017] Preferably, the water separation rate of the thermoreversible gel carrier after being placed for 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., and more preferably ≤5%.

[0018] In the present invention, water extraction refers to the phenomenon that water seeps out 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 as described in the first aspect, the preparation method comprising the following steps:

[0020] (1) K-carrageenan, locust bean gum, agar and water are mixed, heated and stirred until the solution boils, and cooled to the infusion temperature to obtain an infusion gel solution;

[0021] (2) Injecting the injection glue obtained in step (1) into a mold and cooling it 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 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 then fully mixed.

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

[0026] Preferably, the 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, etc.), 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 time is preferably 10-20 min, 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, and then affect the dissolution and hydration degree of each component of the preparation raw material, and have a slight effect on the melting temperature of the thermoreversible gel carrier finally obtained; if the preheating time is short, the hydration is insufficient, the strength decreases, and if the preheating time is long, the effect is not obvious, but the efficiency is low. The preheating can improve the preparation efficiency of the thermoreversible gel carrier and make each component of the preparation raw material fully absorb water and expand. If preheating is not performed, the preparation process takes a long time, the dissolution or swelling effect is poor, and the gel performance is 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 will only slowly swell in cold water, and will not start to dissolve until the temperature is ≥70°C; locust bean gum is only partially dissolved in cold water and needs to be heated to 85°C and maintained for more than 10 minutes to be completely dissolved; agar begins to dissolve at 95°C, and all K-carrageenan, locust bean gum and agar can be completely dissolved by heating and stirring until the solution boils, 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, etc.), 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, is suitable for narrow mold flow channels, and does not require additional pressurizing equipment.

[0034] It should be noted that the selection of the infusion temperature can be made by a person skilled in the art according to the shape, size, complexity, etc. of the mold structure in combination with the actual situation. In addition, although the higher the infusion temperature, the better the fluidity, the higher the infusion temperature, the greater the volume shrinkage of the thermoreversible gel carrier formed after cooling. If the infusion temperature is too high, on the one hand, the cooling waiting time is prolonged, and on the other hand, the volume shrinkage of the thermoreversible gel carrier formed is large, which affects the target shape.

[0035] In the present invention, for convenience, the filling tool for injecting the glue solution into the mold is preferably a syringe, and a glue filling machine or a glue dispensing machine can also be used. Those skilled in the art can choose according to actual conditions. In order to keep the surface of the thermoreversible gel carrier clean, 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 prone to water loss, affecting the shape of the thermoreversible gel carrier; and the natural cooling speed 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, etc.), more preferably 20-25°C.

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

[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 having a complex cavity shape.

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

[0044] Preferably, the manufacturing process of the product having a 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 spray coating 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 force to dipping liquid, can be used as a mold for preparing products with cavities, has 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 the 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 This is a 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 specific implementation methods. It should be understood by those skilled in the art that the embodiments are only 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 embodiments and comparative examples are as follows:

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

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

[0054] Locust bean gum: CAS No. 9000-40-2, manufacturer Aladdin;

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

[0056] Low melting point agarose: CAS No. 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 caking. 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 an injection glue solution.

[0060] (2) Use a 50 mL 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. to cool for 5 min. Allow the perfusion glue to cool and set, take it out and hang it in a clean area to obtain the thermoreversible gel carrier, such as Figure 1 shown.

[0061] Example 2

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

[0063] Example 3

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

[0065] Example 4

[0066] This embodiment provides a thermoreversible gel carrier and a preparation method thereof. The difference between this embodiment and embodiment 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 embodiment 1.

[0067] Example 5

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

[0069] Example 6

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

[0071] Example 7

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

[0073] Example 8

[0074] This embodiment provides a thermoreversible gel carrier and a preparation method thereof, which is different from Embodiment 1 only in 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, which is different from Embodiment 1 only in 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, which is different from Embodiment 1 only in that the preheating temperature in step (1) is adjusted to 85° C., and other conditions are the same as those in Embodiment 1.

[0079] Embodiment 11

[0080] This embodiment provides a thermoreversible gel carrier and a preparation method thereof, which is different from Embodiment 1 only in 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 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., and other conditions are the same as those in embodiment 6.

[0085] Embodiment 14

[0086] This embodiment provides a thermoreversible gel carrier and a preparation method thereof. The 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., and other conditions are the same as those in embodiment 1.

[0087] Embodiment 15

[0088] This embodiment provides a thermoreversible gel carrier and a preparation method thereof. The 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., and 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 is different 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 is different 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 is different 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, which is different from Example 1 only in 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 by 5 parts by weight of low-melting-point agarose, and 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 is different 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 is immersed in the dipping solution for dipping, taken out, dried, and immersed in the dipping solution again for dipping. The dipping is repeated 4 times. After the balloon shell layer is formed by the dipping process, demolding is performed, that is, the thermoreversible gel carrier with the balloon shell layer is placed in water and heated to 70°C, and the stainless steel dipping rod is removed to generate balloon holes. The melted liquid of the thermoreversible gel carrier is gently squeezed to discharge the melted liquid of the thermoreversible gel carrier from the balloon holes. Finally, 85°C hot water is sucked 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, which is a heart-shaped balloon, such as Figure 2 shown.

[0102] The above-mentioned 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 carrier provided in Examples 2 to 15 is 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 1~5

[0106] The comparative application examples 1 to 5 provide a balloon, which differs from application example 1 only in that the thermoreversible gel carrier provided in comparative examples 1 to 5 is used to replace the thermoreversible gel carrier provided in embodiment 1, and other conditions are the same as those in application example 1.

[0107] Performance Testing

[0108] The perfusion gel solutions provided in the above-mentioned Examples 1 to 12 and Comparative Examples 1 to 4 were treated as follows to test the gel 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. 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 cool it down naturally until the test tube is tilted at 90° 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 make the overall temperature drop rapidly. A thermoreversible gel carrier is prepared. A small steel ball with a diameter of 8 mm is placed on the thermoreversible gel carrier. The test tube is placed at room temperature for 2 hours, then placed in a 30°C water bath for 10 minutes, and then heated 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 the above-mentioned 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 culture dish was filled with the perfusion glue, and the perfusion glue was cooled to prepare a thermoreversible gel carrier, and then placed at room temperature (25°C) for 2 hours for testing. The test used 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. Repeat three times, the spacing between the test points was >2 cm, and the results were averaged;

[0113] When testing Examples 1-12 and Comparative Examples 1-4, the above cooling is to immerse the part of the test tube containing the injection glue solution in deionized water at 25°C for cooling for 5 minutes, and the water level is at least 2 cm above the top of the injection glue solution, so that the overall temperature drops rapidly;

[0114] When testing Examples 13-15, the above cooling was natural cooling at room temperature of 25°C.

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

[0116] Fill a cylindrical mold with an inner diameter of 3.1 cm and a height of 2.9 cm with the injection glue, immerse the cylindrical mold with the injection glue 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 injection glue, so that the overall temperature drops rapidly to prepare a thermoreversible gel carrier. Then, the water precipitation rate test is carried out. The test environment is maintained at: 25°C ± 2, and the relative humidity is within the range of 50% ± 5%. The prepared thermoreversible gel carrier is weighed and recorded as the initial mass m1 (g); after a period of time, the sample is gently squeezed with a paper towel to remove the water and weighed again. The mass is recorded as m2 (g). The water precipitation rate is calculated according to the following formula;

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

[0118] The water precipitation rates after 1 hour and 2 hours of storage were tested respectively. The smaller the water precipitation rate, the better the water retention 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 conducted.

[0123] Table 2

[0124]

[0125] In the present invention, the thermoreversible gel carrier (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 gel temperature of the thermoreversible gel carrier gradually increases, and the gel strength also gradually increases. The matching K-carrageenan ratio can be selected according to the gel temperature requirements.

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

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

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

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

[0131] By comparing Example 6 with Example 13, by comparing Example 1 with Example 14, and by comparing Example 7 with Example 15, it can be seen that natural cooling and cooling immersed 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] By comparing Example 1 with Comparative Example 2, it can be seen 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 agar is not added (Comparative Example 3), the thermoreversible gel carrier prepared has too low gel strength. If the gel strength is too low, it will deform when hung on the dipping rod, and may even be punctured or ruptured when hung, and cannot meet the use requirements.

[0135] By comparing Example 1 with Comparative Example 4, it can be seen that the gel strength of the thermoreversible gel carrier prepared by low melting point agarose in Comparative Example 4 is too high, the elasticity is poor, and the wall thickness of the balloon (Application Example 4) prepared by using it is only 86.5 μm, which is much lower than the wall thickness of 132.6 μm of the balloon (Application Example 1) prepared by using the thermoreversible gel carrier provided in Example 1, and the adsorption capacity to the dipping liquid is low. The wall thickness of the balloon prepared by Application Examples 2 to 15 is similar to that of Application Example 1, which shows that the thermoreversible gel carrier prepared by compounding K-carrageenan, locust bean gum and agar in the present invention has a high gel temperature, suitable gel strength, and good adsorption capacity to the dipping liquid.

[0136] It can be seen from Table 2 that, compared with Example 1, if locust bean gum is not added (Comparative Example 5), the water separation rate of the obtained thermoreversible gel carrier is high. From the comparison between Comparative Example 5, Examples 1 and 4, it can be seen that with the use and increase of the amount of locust bean gum, the water separation rate gradually decreases.

[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, suitable gel strength, low water separation 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 declares that the present invention illustrates the process method of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned process steps, that is, it does not mean that the present invention must rely on the above-mentioned process steps to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A thermoreversible gel carrier, characterized in that: The thermoreversible gel carrier comprises the following components in parts 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.

2. The thermoreversible gel carrier according to claim 1, characterized in that: The mass ratio of the locust bean gum to K-carrageenan is 1:(1-5).

3. The thermoreversible gel carrier according to claim 1, characterized in that: The gel strength of the thermoreversible gel carrier is 400-2000 g / cm 2 ; The melting temperature of the thermoreversible gel carrier is ≤90°C; The water separation rate of the thermoreversible gel carrier after being placed for 2 hours is ≤7%.

4. A method for preparing a thermoreversible gel carrier according to any one of claims 1 to 3, 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 infusion temperature to obtain an infusion gel solution; (2) Injecting the injection glue obtained in step (1) into a mold and cooling it to obtain the thermoreversible gel carrier.

5. The preparation method according to claim 4, characterized in that: The mixing in step (1) includes any one of stirring mixing, centrifugal mixing or oscillating mixing; The heating and stirring in step (1) is performed at a speed of 200-500 rpm.

6. The preparation method according to claim 4, 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 min.

7. The preparation method according to claim 4, characterized in that: The perfusion temperature is 50-100°C.

8. The preparation method according to claim 4, characterized in that: The cooling in step (2) includes any one of cooling by immersion in a cooling medium, air cooling or natural cooling.

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

10. Use of the thermoreversible gel carrier according to any one of claims 1 to 3 in the manufacture of a product with a cavity.

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