High-stripping-force medical silica gel and preparation method thereof

Abstract

The invention discloses medical silica gel with high stripping force and a preparation method thereof. The medical silica gel is prepared from the following raw materials in parts by mass: 41 to 46 parts of vinyl-terminated polydimethylsiloxane, 22 to 28 parts of hydroxyl-terminated polydimethylsiloxane, 13 to 10 parts of hydrogen-terminated polymethylsiloxane B, 13 to 22 parts of hydrogen-terminated polymethylsiloxane B, 4 to 10 parts of MQ silicon resin and 0.15 to 0.18 part of vinyl single end socket. The invention relates to a high-temperature-resistant coating which is prepared from the following components in parts by mass: 0.5 to 0.6 part of vinyl silazane, 1.2 to 1.5 parts of hexamethyl disilazane, 0 to 0.5 part of platinum catalyst and 0.01 to 0.05 part of inhibitor. By reducing the addition amount of the silicon resin and carrying out bridging treatment and dehydroxylation treatment between the silicon resin and the silicone oil, the silicone oil is pre-connected to a silicon resin network so as to improve the compatibility of the silicon resin and the silicone oil, and meanwhile, the storage stability of the whole silicon gel system is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of silicone gel, in particular to a high-peeling-strength medical silicone gel and a preparation method thereof BACKGROUND

[0002] The adhesion of silicone gel to the substrate and skin is achieved by using the incomplete curing and adhesion of silicone gel. To obtain a medical adhesive silicone gel with high peeling strength, there are generally two ways. One is to increase the thickness of the silicone gel coating layer to 200-400 microns, and the other is to add a high content of methyl MQ silicone resin (35%) to achieve the above-mentioned effect. However, both methods have certain disadvantages. In the first method, although the peeling strength can be improved, the preparation cost of the product is increased, and the air permeability is poor during use. In the second method, the addition of a high content of methyl MQ silicone resin also increases the cost of the product, and on the other hand, since the methyl MQ silicone resin does not participate in the reaction, it leads to poor compatibility with the silicone oil system, thereby affecting the adhesion of the silicone gel to the substrate, and the adhesive layer is easily peeled off from the surface of the substrate. At the same time, the addition of a large amount of silicone resin causes obvious pain when the skin is torn.

[0003] CN109415563B discloses a skin-adhesive silicone gel and a precursor composition thereof, which comprises a vinyl-containing organopolysiloxane, a Si-H functional chain extender CE, and a crosslinker XL (containing 15.1%-40.0% Si-H), and strictly controls three key molar ratio parameters, namely, RHAlk (total Si-H / Vi≥4.5), RH CE V (chain extender Si-H / Vi≥4.5), and the proportion of chain extender Si-H (≥90%). The obtained gel has excellent skin adhesion (peeling energy≥14 mJ / cm 2 ), strong substrate adhesion, and moderate softness (penetration 80-300 mm / 10), and is suitable for medical dressings, breast prostheses, and medical sensor fixation, etc. It does not require additional adhesive primer treatment, and has good biocompatibility and use comfort. However, it does not mention how to achieve a silicone gel with high peeling strength.

[0004] CN108350339B discloses a silicone gel that can be applied in the medical field or in the electronics department. By controlling the use of long-chain end-side hydrogen-containing silicone oil and end-hydrogen silicone oil, the long-chain crosslinker has a low Si-H density, the number of SiH groups is 2.5-3.5 per molecule, and the hydrogen content is ≤0.025%, and a vinyl MQ silicone resin is used to enhance the network strength, balance the adhesion and mechanical properties, and achieve a silicone gel with high adhesion and no residue. The invention tests the 90° peeling strength. However, experiments show that the 90° peeling strength is at least 100 g / in larger than the 180° peeling strength in numerical value. Therefore, it still does not achieve high peeling strength.

[0005] CN112063330B discloses a medical pressure-sensitive silicone gel and its preparation method and application, which raw materials include 90-97% of methyl vinyl siloxane-dimethyl siloxane copolymer, 2.5-7.5% of polymethyl hydrogen siloxane, 0.5-5% of MQ silicone resin and not more than 5% of catalyst, which are mixed in proportion to prepare A and B glue, the viscosity of the silicone gel is 11500-13200 mPa·s, the penetration is 155-200 (1 / 10 mm), the weight is 200 g / m 2 The peel strength is 250-860 g / cm at a coating amount, and the silicone gel has the advantages of stable structure, strong cohesion, high viscosity, soft comfort, less skin irritation and the like, and can be used to prepare medical adhesive tape and other gel products loaded on substrates such as non-woven fabric and PU film. Although the patent relates to a silicone gel with high peel strength, it does not involve specific material types and special requirements. SUMMARY

[0006] The present application provides a high peel strength medical silicone gel, which solves the compatibility problem of silicone resin and silicone oil system by bridging, improves the cohesion strength of the silicone gel itself, makes the silicone gel not easy to drop glue in the cutting and peeling process, and at the same time can realize thin coating of silicone gel to obtain high peel strength.

[0007] The technical scheme provided by the present application is as follows: a high peel strength medical silicone gel is prepared from the following raw materials:

[0008] Vinyl-terminated polydimethylsiloxane 41-46 parts by mass, hydroxyl-terminated polydimethylsiloxane 22-28 parts by mass, hydrogen-terminated polymethylsiloxane B 13-10 parts by mass, hydrogen-terminated polymethylsiloxane B2 13-22 parts by mass, methyl MQ silicone resin 4-10 parts by mass, vinyl single seal head 0.15-0.18 parts by mass, vinyl silazane 0.5-0.6 parts by mass, hexamethyl disilazane 1.2-1.5 parts by mass, platinum catalyst 0-0.5 parts by mass, inhibitor 0.01-0.05 parts by mass.

[0009] In the experiment of the silicone gel, the inventor found that when using a single hydrogen-terminated silicone oil, it is difficult to adjust the crosslinking network spacing of the silicone gel system, resulting in unstable silicone gel system. By selecting two kinds of hydrogen-terminated silicone oils, the hydrogen content can be well adjusted, and the crosslinking density can be dispersed, so that the silicone gel maintains good skin friendliness.

[0010] Another object of the present application is to provide a preparation method of the high peel strength medical silicone gel.

[0011] The preparation method of the high peel strength medical silicone gel comprises the following steps:

[0012] (1) Preparation of 20% silicone resin oil solution:

[0013] The hydroxyl-terminated polydimethylsiloxane is taken in the above-mentioned proportion, then the vinyl single end cap is added, after stirring for 15 min, the acetic acid solution is added, the temperature is raised to 50-55°C under reflux, and the reaction is carried out for 20 min; the methyl MQ silicone resin in 50% ethyl acetate solution is added, stirring is carried out for 1 hour, the vinyl silazane and hexamethyl disilazane are added, stirring is carried out for 1 hour, then the temperature is raised to 90°C, the reaction is carried out for 1 hour, the temperature is continuously raised to 130°C, the nitrogen gas is started to be passed at 0.5 L / min, and vacuum is applied to remove the ethyl acetate and excess ammonia, when the tail gas pH = 7, the heating and vacuum are stopped, and filtration is carried out to obtain 20% silicone resin solution oil;

[0014] (2) Silicone gel preparation:

[0015] The vinyl-terminated polydimethylsiloxane is taken in the above-mentioned proportion, and is mixed uniformly with 20% silicone resin solution oil, the inhibitor and platinum gold catalyst are added and uniformly mixed, and finally the hydrogen-terminated polymethylsiloxane B1 and hydrogen-terminated polymethylsiloxane B2 are added, and vacuum degassing is carried out.

[0016] In an optional embodiment,

[0017] The viscosity of the vinyl-terminated polydimethylsiloxane is 20-280 million mPa·s, preferably 2-20 million mPa·s, and more preferably 2-16 million mPa·s.

[0018] The viscosity of the hydroxyl-terminated polydimethylsiloxane is 5,000-20,000 mPa·s, preferably 6,000-15,000 mPa·s, and more preferably 8,000-15,000 mPa·s.

[0019] The hydrogen-terminated polymethylsiloxane B1 is a hydrogen-terminated silicone oil prepared by using a cationic resin as a catalyst, and the viscosity is 10-220 mPa·s, preferably 80-220 mPa·s, and more preferably 100-220 mPa·s.

[0020] The hydrogen-terminated polymethylsiloxane B2 is a hydrogen-terminated silicone oil prepared by using a cationic resin as a catalyst, and the viscosity is 300-800 mPa·s, preferably 350-800 mPa·s, and more preferably 400-800 mPa·s.

[0021] The methyl MQ silicone resin has a number average molecular weight of 3,000-3,800, an M / Q value of 0.7, and a hydroxyl content of 3-8%, preferably 3-6%, and more preferably 3-5%.

[0022] The platinum gold catalyst is a Karstedt platinum gold catalyst with a content of 2,000-20,000 ppm, preferably 3,000-5,000 ppm, and more preferably 4,500-5,000 ppm.

[0023] The inhibitor is one or more of ethynylcyclohexanol, tetramethyldivinylsiloxane, tetramethyltetraethenylcyclotetrasiloxane, and more preferably tetramethyldivinylsiloxane.

[0024] Advantages of the present application:

[0025] The preparation method of the thin coating high peel strength silicone gel provided by the present application reduces the amount of silicone resin added, performs bridging treatment and dehydroxy treatment between the MQ silicone resin and the silicone oil (hydroxyl-terminated polydimethylsiloxane), so that the silicone oil is pre-connected to the silicone resin network and the compatibility of the silicone resin and the silicone oil is improved, while the storage stability of the entire silicone gel system is ensured. The silicone resin oil in the present application is not a mixture of silicone resin and silicone oil in the traditional sense, but a self-made silicone resin oil system that bonds the silicone oil system and the silicone resin together through chemical reaction.

[0026] In the present application, the hydroxyl-terminated polydimethylsiloxane is first partially end-capped to obtain a single-end hydroxyl vinyl silicone oil, then a high-hydroxyl-content methyl MQ silicone resin is added, and under acid catalysis, the silicone oil and the methyl MQ silicone resin are condensed to graft the silicone oil to the molecular chain of the methyl MQ silicone resin, then vinyl silazane and hexamethyldisilazane are added to remove the residual hydroxyl groups in the silicone resin to obtain an MQ silicone resin oil, and the flexible chain segment is connected to the silicone resin system to change the rigid structure of the silicone resin, which can also play a role in dispersing the crosslinking density in the silicone gel.

[0027] In the present application, the amount of pure silicone resin accounts for only 4-10% of the entire system, which can achieve the effect of thin coating and high peel strength of 150 g / in.

[0028] In conventional silicone gel formulations, end-hydrogen plus side-hydrogen or end-side hydrogen-containing silicone oil is used as a crosslinking agent, but due to the slow reaction rate of side hydrogen in the reaction system, the side hydrogen cannot be completely reacted in the process of online coating due to the short time, which leads to the continuous reaction of side hydrogen with the vinyl group in the system during the later storage process, resulting in the phenomenon of reduced adhesion and peel strength of the silicone gel. In the present application, no side chain containing hydrogen is added, and methyl MQ silicone resin oil is used to match end-vinyl silicone oil, and two high and low viscosity end-hydrogen silicone oils are used. The silicone resin oil provides a basic crosslinking network function, and the presence of the chain-extending end hydrogen can average the network to achieve the same or even better reinforcement effect, realizing thin coating of the silicone gel to obtain high peel strength, and the phenomenon of adhesion decay during storage does not occur. DETAILED DESCRIPTION

[0029] The detailed description of the various exemplary embodiments of the present application should not be considered as limiting the present application, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present application.

[0030] Coating:

[0031] The silicone gel was coated on the surface of the substrate by a 50-micron coater, and after baking at 120°C for 10 min, the release film was wound

[0032] 180° peel force test:

[0033] The adhesive tape was cut into 125 mm * 25 mm and attached to the surface of a smooth steel plate, and after standing at room temperature for 20 min, the 180° peel force test was performed.

[0034] The mass of the gel was measured using a penetrometer according to the needle penetration method according to standard ISO-2137, in which the total weight of the rod and cone was fixed at 150 g. The cone penetration of the silicone gel was determined by measuring the depth of penetration of the cone into the sample at 25°C, which was obtained by releasing the cone assembly and allowing the cone to act for 5 seconds. The result was expressed in 1 / 10 mm.

[0035] Example 1

[0036] Vinyl-terminated polydimethylsiloxane: 100,000 mPa-s, vinyl content 0.07%, 43.6 parts by mass;

[0037] Hydroxyl-terminated polydimethylsiloxane: 10,000 mPa-s, 0.14% hydroxyl content, 26.4 parts by mass;

[0038] Hydrogen-terminated polymethylsiloxane:

[0039] Hydrogen-terminated polymethylsiloxane B1: 120 mPa-s, hydrogen content 0.034%, 3.18 parts by mass;

[0040] Hydrogen-terminated polymethylsiloxane B2: 480 mPa-s, hydrogen content 0.015%, 20 parts by mass;

[0041] Methyl MQ silicone resin: hydroxyl content 3.5%, number average molecular weight 3500, M / Q value 0.7, 6.6 parts by mass;

[0042] Vinyl monoblock: 0.2 parts by mass;

[0043] Vinyl silazane: 0.65 parts by mass;

[0044] Hexamethyldisilazane: 1.59 parts by mass;

[0045] 5000 ppm platinum gold catalyst: 0.2 parts by mass;

[0046] Tetramethyldivinyl disiloxane: 0.02 parts by mass.

[0047] Take 26.4 parts by mass of 10000 mPa·s hydroxyl silicone oil, then add 0.2 parts by mass of vinyl single end cap, stir for 15 min, then add 0.13 parts by mass of acetic acid solution, then reflux to 50-55℃, react for 20 min. Add 13.2 parts by mass of 50% methyl MQ silicone resin in ethyl acetate solution into a three-necked flask, stir for 1 hour, add 0.65 parts by mass of vinyl silazane and 1.59 parts by mass of hexamethyl disilazane, stir for 1 hour, then stir to 90℃, react for 1 hour, continue to heat to 130℃, start nitrogen flow 0.5L / min, and vacuum, remove ethyl acetate and excess ammonia, when the tail gas PH = 7, stop heating and vacuum, filter to get 20% silicone resin solution oil.

[0048] Then mix the vinyl-terminated polydimethylsiloxane with the obtained silicone resin solution oil under the action of a high-speed disperser, add inhibitor tetramethyl divinyl disiloxane and platinum gold catalyst, continue to mix uniformly, finally add hydrogen-terminated polymethylsiloxane, stir uniformly, and vacuum degassing for 3 min.

[0049] Coat the silicone gel on the surface of the substrate through a 50-micron coater, and bake at 120℃ for 10 min.

[0050] Prepare 150 g of silicone gel, mix uniformly, vacuum degassing, load into a standard measuring cup, take out at 120℃*60 min, test the cone penetration after standing at room temperature for 24 H.

[0051] Example 2

[0052] Vinyl-terminated polydimethylsiloxane: 150,000 mPa·s, vinyl content 0.024%, 41.5 parts by mass;

[0053] Hydroxyl-terminated polydimethylsiloxane: 10,000 mPa·s, 0.14% hydroxyl content, 26.4 parts by mass;

[0054] Hydrogen-terminated polymethylsiloxane:

[0055] Hydrogen-terminated polymethylsiloxane B1: 120 mPa·s, hydrogen content 0.034%, 3.3 parts by mass;

[0056] Hydrogen-terminated polymethylsiloxane B2: 750 mPa·s, hydrogen content 0.011%, 22 parts by mass;

[0057] Methyl MQ silicone resin: hydroxyl content 3.5%, number average molecular weight 3500, M / Q value 0.7, 6.6 parts by mass;

[0058] Vinyl single end cap: 0.2 parts by mass;

[0059] Vinyl silazane: 0.65 parts by mass;

[0060] Hexamethyldisilazane: 1.59 parts by mass;

[0061] 5000 ppm platinum catalyst: 0.2 parts by mass;

[0062] Tetramethyldivinyl disiloxane: 0.02 parts by mass.

[0063] Take 26.4 parts by mass of 10000 mPa-s hydroxyl silicone oil, then add 0.2 parts by mass of vinyl monoblock, after stirring for 15 min, add 0.13 parts by mass of acetic acid solution, then reflux to 50-55℃, react for 20 min. Add 13.2 parts by mass of 50% methyl MQ silicone resin in ethyl acetate solution into a three-necked flask, stir for 1 hour, add 0.65 parts by mass of vinyl silazane and 1.59 parts by mass of hexamethyldisilazane, stir for 1 hour, then stir to 90℃, react for 1 hour, continue to heat to 130℃, start nitrogen flow 0.5 L / min, and vacuum, remove ethyl acetate and excess ammonia, when the tail gas PH = 7, stop heating and vacuum, filter to obtain 20% silicone resin solution.

[0064] Then mix the vinyl-terminated polydimethylsiloxane with the obtained silicone resin solution under the action of a high-speed disperser, add the inhibitor tetramethyldivinyl disiloxane and platinum catalyst, continue to mix uniformly, finally add the hydrogen-terminated polymethylsiloxane, stir uniformly, and vacuum degassing for 3 min.

[0065] Coat the silicone gel on the surface of the substrate through a 50-micron coater, and bake at 120℃ for 10 min.

[0066] Prepare 150 g of silicone gel, mix uniformly, vacuum degassing, load into a standard measuring cup, take out at 120℃*60 min, and test the cone penetration after standing at room temperature for 24 H.

[0067] Example 3

[0068] Vinyl-terminated polydimethylsiloxane: 60,000 mPa-s, vinyl content 0.08%, 45 parts by mass;

[0069] Hydroxyl-terminated polydimethylsiloxane: 10,000 mPa-s, 0.14% hydroxyl, 26.4 parts by mass;

[0070] Hydrogen-terminated polymethylsiloxane:

[0071] Hydrogen-terminated polymethylsiloxane B1: 200 mPa-s, hydrogen content 0.025%, 6.82 parts by mass;

[0072] Hydrogen-terminated polymethylsiloxane B2: 480 mPa-s, hydrogen content 0.016%, 15 parts by mass;

[0073] Methyl MQ silicone resin: hydroxyl content 3.5%, number average molecular weight 3500, M / Q value 0.7, 6.6 parts by mass;

[0074] Vinyl mono-capped: 0.2 parts by mass;

[0075] Vinyl silazane: 0.65 parts by mass;

[0076] Hexamethyl disilazane: 1.59 parts by mass;

[0077] 5000 ppm platinum catalyst: 0.2 parts by mass;

[0078] Tetramethyl divinyl disiloxane: 0.02 parts by mass.

[0079] Take 26.4 parts by mass of 10000 mPa-s hydroxyl silicone oil, then add 0.2 parts by mass of vinyl mono-capped, stir for 15 min, then add 0.13 parts by mass of acetic acid solution, then reflux to 50-55°C, react for 20 min. Add 13.2 parts by mass of 50% methyl MQ silicone resin in ethyl acetate to a three-necked flask, stir for 1 h, then add 0.65 parts by mass of vinyl silazane and 1.59 parts by mass of hexamethyl disilazane, stir for 1 h, then stir to 90°C, continue to heat to 130°C, start nitrogen flow at 0.5 L / min, and vacuum, remove ethyl acetate and excess ammonia, when the tail gas PH = 7, stop heating and vacuum, filter to obtain 20% silicone resin solution.

[0080] Then mix the vinyl-capped polydimethylsiloxane with the obtained silicone resin solution in a high-speed disperser, add the inhibitor tetramethyl divinyl disiloxane and platinum catalyst, continue to mix uniformly, finally add the hydrogen-terminated polymethylsiloxane, stir uniformly, and vacuum degassing for 3 min.

[0081] Coat the silicone gel on the surface of the substrate through a 50-micron coater, and bake at 120°C for 10 min.

[0082] Prepare 150 g of silicone gel, mix uniformly, vacuum degassing, load into a standard measuring cup, take out at 120°C*60 min, and test the cone penetration after standing at room temperature for 24 h.

[0083] Comparative Example 1

[0084] Vinyl-capped polydimethylsiloxane: 100,000 mPa-s, vinyl content 0.07%, 43.6 parts by mass;

[0085] Vinyl-capped polydimethylsiloxane: 10,000 mPa-s, vinyl content 0.14%, 26.4 parts by mass;

[0086] End-hydrogen polymethylsiloxane:

[0087] End-hydrogen polymethylsiloxane B1: 120 mPa-s, hydrogen content 0.034%, 3.17 parts by mass;

[0088] End-hydrogen polymethylsiloxane B2: 480 mPa-s, hydrogen content 0.015%, 20 parts by mass;

[0089] Methyl vinyl MQ silicone resin: vinyl content 1.1%, number average molecular weight 3500, hydroxyl content ≤0.5%, M / Q value 0.7, 6.6 parts by mass;

[0090] 5000 ppm platinum catalyst: 0.2 parts by mass;

[0091] Tetramethyldivinyl disiloxane: 0.02 parts by mass.

[0092] Take 26.4 parts by mass of 10000 mPa-s vinyl silicone oil, add 13.2 parts by mass of a 50% vinyl MQ silicone resin ethyl acetate solution to a three-necked flask, stir for 1H, warm to 90°C and stir for 1 hour, continue to warm to 130°C, start nitrogen flow at 0.5L / min, and vacuum, remove the ethyl acetate, stop heating and vacuum, and filter to obtain a 20% silicone resin oil.

[0093] Then mix the vinyl-terminated polydimethylsiloxane with the obtained silicone resin oil under the action of a high-speed disperser, add the inhibitor tetramethyldivinyl disiloxane and platinum catalyst, continue to mix uniformly, finally add end-hydrogen polymethylsiloxane, stir uniformly, and vacuum degassing for 3 minutes.

[0094] Coat the silicone gel on the surface of the substrate through a 50-micron coater, and bake at 120°C for 10 minutes.

[0095] Prepare 150 g of silicone gel, mix uniformly, vacuum degassing, load into a standard measuring cup, take out at 120°C*60min, and test the cone penetration after standing at room temperature for 24H.

[0096] Comparative Example 2

[0097] Vinyl-terminated polydimethylsiloxane: 100,000 mPa-s, vinyl content 0.07%, 16.6 parts by mass;

[0098] Vinyl-terminated polydimethylsiloxane: 10,000 mPa-s, vinyl content 0.14%, 30 parts by mass;

[0099] End-hydrogen polymethylsiloxane:

[0100] Hydrogen-terminated polydimethylsiloxane B1 : 45 mPa-s, hydrogen content 0.034%, 3.17 parts by mass;

[0101] Hydrogen-terminated polydimethylsiloxane B2: 480 mPa-s, hydrogen content 0.015%, 20 parts by mass;

[0102] Methyl MQ silicone resin: number average molecular weight 3500, hydroxyl content <0.5%, M / Q value 0.7, 25 parts by mass;

[0103] 5000 ppm platinum catalyst: 0.2 parts by mass;

[0104] Tetramethyldivinyl disiloxane: 0.02 parts by mass.

[0105] Take 26.4 parts by mass of 10000 mPa-s vinyl silicone oil, add 50 parts by mass of an ethyl acetate solution containing 50% methyl MQ silicone resin to a three-necked flask, stir for 1 H, warm to 90°C and stir for 1 hour, continue to warm to 130°C, start nitrogen flow at 0.5 L / min, and vacuum, remove the ethyl acetate, stop heating and vacuum, filter to obtain 48.6% silicone resin oil.

[0106] Then mix the vinyl-terminated polydimethylsiloxane with the obtained silicone resin oil under the action of a high-speed disperser, add the inhibitor tetramethyldivinyl disiloxane and platinum catalyst, continue to mix uniformly, finally add hydrogen-terminated polydimethylsiloxane, stir uniformly, and vacuum degassing for 3 min.

[0107] Coat the silicone gel on the surface of the substrate by a 50-micron coater, and bake at 120°C for 10 min.

[0108] Prepare 150 g of silicone gel, mix uniformly, vacuum degassing, load into a standard measuring cup, take out at 120°C*60 min, and test the cone penetration after standing at room temperature for 24 H.

[0109] Table 1:

[0110]

[0111] As can be seen from Table 1, the present application bonds the silicone oil system and the silicone resin together to form self-made silicone resin dissolving oil, and matches different end hydrogen-containing silicone oils to adjust the crosslinking network spacing of the silicone gel system, disperse the crosslinking density, make the silicone gel cone penetration higher, keep certain softness, thus achieve better skin-friendly feeling, and the more dispersed silicone resin system gets higher peel strength. Comparative Examples 1-2 are both simple mixing of silicone resin and silicone oil without chemical reaction. Comparative Example 1 uses vinyl silicone resin, and the final obtained silicone gel has higher crosslinking density, smaller cone penetration, and cannot get higher peel strength. In order to get higher peel strength, Comparative Example 2 adds a large amount of methyl silicone resin, although the peel strength is improved, but the adhesion to the substrate is poor, there are residual glue on the steel plate and the skin surface, and the skin-friendly feeling of the glue is poor, and there is a tight feeling.

[0112] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application should be equivalent replacement methods, and are all included in the protection scope of the present application.

Claims

1. A high-peel-strength medical silicone gel, characterized in that, It is prepared from the following raw materials: The composition includes: 41-46 parts by weight of vinyl-terminated polydimethylsiloxane, 22-28 parts by weight of hydroxyl-terminated polydimethylsiloxane, 3-10 parts by weight of hydrogen-terminated polymethylsiloxane B1, 3-22 parts by weight of hydrogen-terminated polymethylsiloxane B2, 4-10 parts by weight of MQ silicone resin, 0.15-0.18 parts by weight of vinyl-terminated polydimethylsiloxane, 0.5-0.6 parts by weight of vinylsilazane, 1.2-1.5 parts by weight of hexamethyldisilazane, 0-0.5 parts by weight of platinum catalyst, and 0.01-0.05 parts by weight of inhibitor.

2. The high peel strength medical silicone gel according to claim 1, characterized in that, The vinyl-terminated polydimethylsiloxane has a viscosity of 20,000-280,000 mPa·s.

3. The high peel strength medical silicone gel according to claim 1, characterized in that, The hydroxyl-terminated polydimethylsiloxane has a viscosity of 5000-20000 mPa·s.

4. The high peel strength medical silicone gel according to claim 1, characterized in that, The terminal hydrogen polymethylsiloxane B1 is a terminal hydrogen silicone oil prepared by using cationic resin as a catalyst, and its viscosity is 10-220 mPa·s.

5. The high peel strength medical silicone gel according to claim 1, characterized in that, The terminal hydrogen polymethylsiloxane B2 is a terminal hydrogen silicone oil prepared by using cationic resin as a catalyst, and its viscosity is 300-800 mPa·s.

6. The high peel strength medical silicone gel according to claim 1, characterized in that, The MQ silicone resin has a number average molecular weight of 3000-3800, an M / Q value of 0.7, and a hydroxyl content of 3-8%.

7. The high peel strength medical silicone gel according to claim 1, characterized in that, The platinum catalyst is a 2000-20000 ppm castor platinum catalyst.

8. The high peel strength medical silicone gel according to claim 1, characterized in that, The inhibitor is one or more of acetylenecyclohexanol, tetramethyldivinylsiloxane, and tetramethyltetravinylcyclotetrasiloxane.

9. A method for preparing the high peel strength medical silicone gel according to any one of claims 1-8, characterized in that, Includes the following steps: (1) Preparation of 20% silicone resin solvent: Take hydroxyl-terminated polydimethylsiloxane according to the above proportion, then add vinyl-terminated polydimethylsiloxane, stir for 15 min, add acetic acid solution, reflux and heat to 50-55℃, react for 20 min; add ethyl acetate solution containing 50% methyl MQ silicone resin, stir for 1 hour, add vinylsilazane and hexamethyldisilazane, stir for 1 hour, heat to 90℃ and react for 1 hour, continue to heat to 130℃, start to purge nitrogen gas at 0.5 L / min and evacuate to remove ethyl acetate and excess ammonia. When the pH of the tail gas is 7, stop heating and vacuuming, filter to obtain 20% silicone resin oil; (2) Preparation of silica gel: According to the above proportion, vinyl-terminated polydimethylsiloxane is first mixed evenly with the 20% silicone resin solvent. After adding the inhibitor and platinum catalyst and continuing to mix evenly, hydrogen-terminated polymethylsiloxane B1 and hydrogen-terminated polymethylsiloxane B2 are finally added, and vacuum degassing is performed to obtain the final product.

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