Pressure-sensitive adhesive for skin bonding and its products

Abstract

The present invention relates to the field of adhesive technology, and in particular to a pressure-sensitive adhesive for skin bonding and its products. The pressure-sensitive adhesive for skin bonding comprises the following components in parts by weight: 70 to 90 parts of acrylic resin, 10 to 30 parts of nitrile rubber, 0.1 to 0.5 parts of initiator, 10 to 40 parts of tackifying resin and 0.05 to 0.5 parts of cross-linking agent; wherein the total amount of the acrylic resin and the nitrile rubber is 100 parts. The pressure-sensitive adhesive of the present invention has excellent air permeability, sebum resistance and bonding performance. It will not cause abnormal skin symptoms when worn on the skin for more than two weeks, and it will not fall off, which can meet the requirements of most application scenarios.

Description

Technical Field

[0001] The invention relates to the technical field of adhesives, in particular to a pressure-sensitive adhesive for skin bonding and a product thereof. Background Art

[0002] With the development of medical device technology, more and more electronic sensor products are used to monitor multiple life and health indicators in human medicine. Generally, it is a simpler solution to use adhesive sheets to fix such sensors at specific locations on the skin for monitoring. Adhesives that can generally be used for such adhesive sheets include polyacrylate, rubber, silicone and polyurethane pressure-sensitive adhesives.

[0003] Such medical adhesive sheets need to meet the following requirements: (1) Since the adhesive sheet directly adheres to the skin, it should not contain or contain less than a limited range of substances that are allergenic to the skin; (2) It must pass cytotoxicity tests and meet the standards for use of medical devices; (3) It must have good air permeability to avoid adverse effects on the skin caused by long-term adhesion; (4) It must be able to withstand human secretions such as sweat and sebum, and its bonding performance can be guaranteed. However, it is difficult for adhesive sheets currently used for skin adhesion to meet the above requirements at the same time.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The first aspect of the present invention provides a pressure-sensitive adhesive for skin bonding, which can simultaneously meet the requirements of an adhesive sheet for skin bonding with respect to sensitization, toxicity, air permeability, adhesion and sebum resistance.

[0006] The second aspect of the present invention provides a pressure-sensitive adhesive product made from the skin bonding pressure-sensitive adhesive provided by the first aspect of the present invention.

[0007] In order to achieve the above-mentioned purpose of the present invention, the present invention provides a pressure-sensitive adhesive for skin bonding, comprising the following components in parts by weight: 70 to 90 parts of acrylic resin, 10 to 30 parts of nitrile rubber, 0.1 to 0.5 parts of initiator, 10 to 40 parts of tackifying resin and 0.05 to 0.5 parts of cross-linking agent; wherein the total amount of the acrylic resin and the nitrile rubber is 100 parts.

[0008] Furthermore, the acrylonitrile content in the nitrile rubber is 16% to 20%.

[0009] Furthermore, the initiator includes an organic peroxide initiator.

[0010] Furthermore, the tackifying resin includes at least one of hydrogenated rosin resin, terpene resin, terpene phenolic resin and petroleum resin.

[0011] Furthermore, the softening point of the tackifying resin is higher than 100°C.

[0012] Furthermore, the crosslinking agent is selected from multifunctional acrylate monomers, such as a monomer with a functionality of 2-6.

[0013] Furthermore, the multifunctional acrylate monomer includes at least one of 1,6-hexanediol diacrylate, ethoxylated trimethylolpropane triacrylate and dipentaerythritol hexaacrylate.

[0014] The present invention also provides a method for preparing any one of the above-mentioned pressure-sensitive adhesives, comprising the following steps:

[0015] Put the acrylic resin, nitrile rubber, initiator and solvent weighed in proportion into the reactor and heat to react for 4 to 8 hours; after cooling to room temperature, add the tackifying resin and cross-linking agent in proportion, mix and stir evenly, let stand to defoam, and the pressure-sensitive adhesive to be coated can be obtained.

[0016] The second aspect of the present invention provides a pressure-sensitive adhesive product, comprising a base layer and an adhesive layer disposed on at least one side of the base layer; the adhesive layer comprises the pressure-sensitive adhesive described in the first aspect of the present invention.

[0017] Furthermore, the substrate comprises a spunlace nonwoven fabric substrate.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) The pressure-sensitive adhesive of the present invention is grafted with nitrile rubber and acrylic resin, and the oil resistance of the cyanide group introduced in the nitrile rubber can be utilized. The cross-linking degree of the pressure-sensitive adhesive system can be improved by combining a tackifying resin and a cross-linking agent, thereby improving the sebum resistance, cohesive strength and bonding strength of the pressure-sensitive adhesive and extending the service life of the adhesive sheet. In addition, the acrylic resin is a UV hot-melt acrylic resin, which can reduce the residual acrylate monomer in the pressure-sensitive adhesive, so that the pressure-sensitive adhesive meets the sensitization requirements.

[0020] (2) The pressure-sensitive adhesive product made using the pressure-sensitive adhesive of the present invention has excellent air permeability, sebum resistance and adhesion performance. It can be worn on the skin for more than two weeks without causing any abnormal skin symptoms and will not fall off, thus meeting the requirements of most application scenarios. DETAILED DESCRIPTION

[0021] The technical scheme of the present invention will be clearly and completely described below in conjunction with specific embodiments, but it will be appreciated by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work, all belong to the scope of protection of the present invention. If specific conditions are not indicated in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0022] Existing pressure-sensitive adhesives for skin bonding mostly use polyacrylate adhesives, taking into account the performance requirements and cost control of pressure-sensitive adhesives. However, studies have found that polyacrylate adhesives also have some difficult-to-solve problems. For example, there are often unreacted monomers in the polyacrylate adhesive system, and most of these monomers are allergenic substances that can cause skin discomfort; and the long-chain alkyl side chain structure of acrylates leads to poor resistance to non-polar solvents, and thus poor resistance to sebum. After being bonded to the skin, it is easy to cause rapid decay of bonding strength and a short service life.

[0023] Based on this, the first aspect of the present invention provides a pressure-sensitive adhesive for skin bonding, comprising the following components in parts by weight: 70 to 90 parts of acrylic resin, 10 to 30 parts of nitrile rubber, 0.1 to 0.5 parts of initiator, 10 to 40 parts of tackifying resin and 0.05 to 0.5 parts of cross-linking agent; wherein the total amount of the acrylic resin and the nitrile rubber is 100 parts.

[0024] The pressure-sensitive adhesive of the present invention is grafted onto an acrylic resin by introducing an appropriate amount of nitrile rubber. The oil resistance of the cyanide group in the nitrile rubber can enhance the sebum resistance, sweat resistance and other properties of the pressure-sensitive adhesive, thereby extending the service life. The inventors of the present invention have found that if the amount of nitrile rubber is small, the improvement of the sebum resistance, sweat resistance and other properties is not obvious; and when the amount of nitrile rubber is too large, due to the difference in polarity between the nitrile rubber and the acrylic resin system, too much nitrile rubber causes the system compatibility to deteriorate and cannot be used.

[0025] The pressure-sensitive adhesive of the present invention is based on the use of nitrile rubber grafted onto acrylic resin, and a certain amount of tackifying resin and cross-linking agent are added to improve the sebum resistance and air permeability of the adhesive, while ensuring or even improving the cohesive strength and bonding strength of the pressure-sensitive adhesive. In addition, the pressure-sensitive adhesive of the present invention further reduces the cost while meeting the requirements of sensitization, air permeability, adhesion and sebum resistance, and is more conducive to large-scale application.

[0026] The acrylic resin in the present invention adopts UV hot-melt acrylic resin, which can reduce the residual acrylate monomers in the pressure-sensitive adhesive, thereby meeting the sensitization requirements.

[0027] In a specific embodiment of the present invention, the UV hot-melt acrylic resin is at least one of acResin® A 250 UV and acResin® A 260 UV produced by BASF.

[0028] The amount of acrylic resin in the pressure-sensitive adhesive of the present invention is 70 to 90 parts. In different embodiments, it can be 70 parts, 72 parts, 75 parts, 78 parts, 80 parts, 82 parts, 85 parts, 88 parts, 90 parts or any value in between.

[0029] In a specific embodiment of the present invention, the acrylonitrile content in the nitrile rubber is 16% to 20%. For example, in different embodiments, the acrylonitrile content in the nitrile rubber can be 16%, 17%, 18%, 19%, 20% or any value between the two end values. The inventors of the present invention have found that by controlling the acrylonitrile content in the nitrile rubber within this range, the product has better sebum resistance, sweat resistance and processing performance; if the cyanide content is too low, the strengthening effect is not obvious, and if the cyanide content is too high, the nitrile rubber has poor solubility and is difficult to process.

[0030] The amount of nitrile rubber in the pressure-sensitive adhesive of the present invention is 10 to 30 parts. In a specific embodiment, it can be 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, 28 parts, 30 parts or any value between the two ends.

[0031] In the present invention, the total amount of acrylic resin and nitrile rubber is 100 parts.

[0032] In a specific embodiment of the present invention, the initiator may be an organic peroxide initiator, but is not limited thereto, as long as it can initiate a grafting reaction between the nitrile rubber and the acrylic resin.

[0033] The organic peroxide initiator includes at least one of dibenzoyl peroxide, lauroyl peroxide, tert-butyl benzoyl peroxide and cumene peroxide.

[0034] The amount of the initiator in the pressure-sensitive adhesive of the present invention is 0.1 to 0.5 parts. In a specific embodiment, it can be 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts or any value between the two end values.

[0035] In a specific embodiment of the present invention, the tackifying resin comprises at least one of hydrogenated rosin resin, terpene resin, terpene phenolic resin and petroleum resin, wherein the petroleum resin is preferably C5 petroleum resin and C9 petroleum resin. The tackifying resin is preferably terpene phenolic resin.

[0036] In a specific embodiment of the present invention, the softening point of the tackifying resin is higher than 100° C. The use of a tackifying resin with a higher softening point in the present invention can enhance the cohesive strength of the pressure-sensitive adhesive, thereby improving the adhesive performance of the pressure-sensitive adhesive. If the softening point is lower than 100° C., the cohesion of the tape product is relatively poor, and the temperature resistance is also relatively poor.

[0037] The amount of the tackifying resin in the pressure-sensitive adhesive of the present invention is 10 to 40 parts. In a specific embodiment, it can be 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts or any value between the two ends, preferably 20 to 30 parts.

[0038] In a specific embodiment of the present invention, the crosslinking agent is selected from multifunctional acrylate monomers. For example, in different embodiments, the functionality of the crosslinking agent can be 2, 3, 4, 5 or 6. By introducing multifunctional acrylate monomers, the crosslinking degree of the pressure-sensitive adhesive system can be further increased, thereby improving the cohesive stability of the pressure-sensitive adhesive.

[0039] In a specific embodiment of the present invention, the multifunctional acrylate monomer includes at least one of 1,6-hexanediol diacrylate, ethoxylated trimethylolpropane triacrylate and dipentaerythritol hexaacrylate.

[0040] The amount of the crosslinking agent used in the present invention is 0.05 to 0.5 parts. In a specific embodiment, it can be 0.05 parts, 0.1 parts, 0.25 parts, 0.3 parts, 0.4 parts, 0.5 parts or any value between the two end values.

[0041] The pressure-sensitive adhesive of the present invention can be prepared in the presence of a solvent. In a specific embodiment of the present invention, the solvent includes at least one of ethyl acetate, toluene and butanone. The amount of solvent in the pressure-sensitive adhesive of the present invention can be 100 to 300 parts, and in a specific embodiment, it can be 100 parts, 150 parts, 200 parts, 250 parts or 300 parts, or any value between the two end values. The conventional adjustment of the amount of solvent can be performed according to the uniformity of the pressure-sensitive adhesive reaction and the coating viscosity requirements.

[0042] The pressure-sensitive adhesive system of the present invention may also be added with different conventional additives in the art, such as antimicrobial agents, catalysts, stabilizers, etc., according to different needs. The amount of additives added may be adjusted according to different needs.

[0043] The present invention also provides a method for preparing the pressure-sensitive adhesive, comprising the following steps:

[0044] Put the acrylic resin, nitrile rubber, initiator and solvent weighed in proportion into the reactor and heat to react for 4 to 8 hours; after cooling to room temperature, add the tackifying resin and cross-linking agent in proportion, mix and stir evenly, let stand to defoam, and the pressure-sensitive adhesive to be coated can be obtained.

[0045] In a preferred preparation method, the heating temperature can be adjusted according to the type of initiator to initiate graft polymerization, such as 70-90°C, specifically 70°C, 75°C, 80°C, 85°C or 90°C, or any value between the two end values, but not limited to these.

[0046] In a preferred preparation method, the temperature is raised to the reaction temperature under a protective atmosphere (such as nitrogen), and then an initiator is added to carry out the reaction.

[0047] The second aspect of the present invention provides a pressure-sensitive adhesive product, comprising a base layer and an adhesive layer disposed on at least one side of the base layer; the adhesive layer comprises the pressure-sensitive adhesive described in the first aspect of the present invention.

[0048] In a specific embodiment of the present invention, the base layer is a spunlace nonwoven material. The spunlace nonwoven is soft and entangled, has high strength, low linting, and good air permeability. It is used for the base layer, is skin-friendly, and does not affect the bonding performance.

[0049] In a specific embodiment of the present invention, a release film layer is provided on the side of the adhesive layer facing away from the base layer, wherein the release film layer may include polyethylene terephthalate (PET) film, polyimide (PI) film, polyethylene (PE) film, oriented stretch polypropylene (OPP) film, composite release film and other materials.

[0050] The present invention also provides a method for preparing such a pressure-sensitive adhesive product. In actual operation, the adhesive layer can be obtained by coating the adhesive on the surface of the release film, drying and curing it, and then laminating the adhesive layer and the spunlace non-woven fabric base layer through a rubber roller. The coating method is not limited, and roller coating, scraper coating or dip coating can be used. In actual operation, coating can be applied by a coater. The thickness of the adhesive layer can be freely selected according to actual needs, without special limitation, for example, it can be set to 25 to 100 μm, specifically 25 μm, 30 μm, 40 μm, 50 μm, 80 μm, 100 μm or any value between the two end values.

[0051] The pressure-sensitive adhesive product of the present invention can be used for skin adhesion, and specific product types may include but are not limited to tapes, adhesive sheets, labels, and films, and can be cut into products of different shapes according to different needs.

[0052] Some embodiments of the present invention will now be described in detail in the following examples. In the following examples, 1 g represents 1 part.

[0053] The chemical raw materials, reagents and their sources used in the following specific examples are shown in Table 1.

[0054] Table 1 Raw material information

[0055]

[0056] Examples and Comparative Examples

[0057] The proportions of the components of the pressure-sensitive adhesives of the embodiments and comparative examples are shown in Table 2, and they are all prepared according to the following method:

[0058] In a reactor, acrylic resin, nitrile rubber and solvent were added in a mass ratio, stirred thoroughly to dissolve the materials, nitrogen was passed for 1 hour, the temperature was raised to 80 °C and kept warm; then an initiator was added, the reaction was carried out for 6 hours, and then cooled to room temperature; then tackifying resin and cross-linking agent were added in a mass ratio, mixed thoroughly, and allowed to stand for defoaming to obtain a pressure-sensitive adhesive to be coated.

[0059] Table 2 Types and proportions of various material components in the examples and comparative examples (g)

[0060]

[0061] Comparative Example 5

[0062] This comparative example was carried out with reference to Example 1, and a commercially available medical tape with similar uses was used for the following tests.

[0063] Test Case

[0064] The pressure-sensitive adhesive prepared in the above embodiments and comparative examples was coated on a 50 μm PET release film by an applicator and baked in a 120°C oven for 5 min. After being taken out, a spunlace non-woven fabric was covered on the side of the adhesive layer facing away from the release film layer. The release film was then placed facing an ultraviolet light source for UV irradiation curing with a total energy of 3000 mj to obtain a test sample.

[0065] In order to compare and illustrate the performance differences of the pressure-sensitive adhesives of different embodiments and comparative examples, the above test samples were tested. The test results are shown in Table 3. The test methods are referenced as follows.

[0066] 1. 180° peel strength test: Cut the sample into 2.5 cm wide strips, and the test method is carried out in accordance with the international standard ASTMD3330 "Standard for Peel Strength Test of Pressure-Sensitive Tapes", and the test panel is polyethylene (PE). The room temperature peel strength test refers to the test after the adhesive layer is bonded to the panel and placed under the test temperature and humidity conditions for 20 minutes, and the average adhesion required to tear the strip off the panel is recorded, expressed in gf / 25mm.

[0067] 2. Water vapor permeability test: The water vapor permeability test is carried out in accordance with the industry standard YY / T 0148-2006 "General Requirements for Medical Tapes";

[0068] 3. Sebum resistance test: Cut the sample into 25 mm wide strips, stick them on a PE board, let them stand for 20 minutes, then evenly apply sebum on the surface of the tape, let them stand for 30 minutes, wipe off the sebum, and test the 180° peel strength.

[0069] 4. Actual test: Conduct actual test on human skin. Cut the tape into a circle with a diameter of about 3 cm, stick it on the skin, soak it for 20 minutes, and observe the time it takes for it to fall off naturally.

[0070] Table 3 Performance test results

[0071]

[0072] According to the test results in Table 3, the products made of the pressure-sensitive adhesive provided by the present invention have good air permeability, adhesion and sebum resistance. In the actual fitting test, they can be fitted for 18 days or more without falling off, which fully meets the market demand.

[0073] The test results of Example 4 and Comparative Example 2 show that the pressure-sensitive adhesive of the present invention uses a tackifying resin with a softening point above 100°C, which has better product performance; when a low softening point resin is used, the cohesion of the adhesive film is relatively poor, the sebum resistance is poor, and the number of days of adhesion to the skin is short.

[0074] It can be seen from the test results of comparative example 1a that if the amount of nitrile rubber added in the present invention is relatively large relative to the amount of acrylic resin added, the polarity of the two will differ greatly and the compatibility will be limited, and excessive use of nitrile rubber will cause the system to turn white and become unusable; the test results of comparative example 1b show that when the content of nitrile rubber is relatively low relative to the acrylic resin, the polarity of the film is low, the cohesion is poor, the sebum resistance is relatively poor, and the number of days of adhesion to the skin decays rapidly.

[0075] From the test results of Comparative Example 3, it can be seen that when no initiator is contained, the polymer chains cannot be cross-linked, the nitrile rubber and the acrylic resin are only physically mixed, the degree of cross-linking of the system decreases, the sebum resistance is poor, and the number of days of skin adhesion decreases rapidly; from the test results of Comparative Example 4, it can be seen that when no cross-linking agent is contained, the degree of cross-linking of the system decreases, resulting in poor cohesive performance, poor sebum resistance, and a rapid decrease in the number of days of skin adhesion.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A pressure-sensitive adhesive for skin bonding, characterized in that: The invention comprises the following components by weight: 70 to 90 parts of acrylic resin, 10 to 30 parts of nitrile rubber, 0.1 to 0.5 parts of initiator, 10 to 40 parts of tackifying resin and 0.05 to 0.5 parts of crosslinking agent; wherein the total amount of the acrylic resin and the nitrile rubber is 100 parts; The tackifying resin comprises at least one of hydrogenated rosin resin, terpene resin, terpene phenolic resin and petroleum resin; The softening point of the tackifying resin is higher than 100°C.

2. The skin bonding pressure-sensitive adhesive according to claim 1, characterized in that: The acrylonitrile content in the nitrile rubber is 16% to 20%.

3. The skin bonding pressure-sensitive adhesive according to claim 1, characterized in that: The initiator includes an organic peroxide initiator.

4. The skin bonding pressure-sensitive adhesive according to claim 1, characterized in that: The acrylic resin is a UV hot melt type.

5. The skin bonding pressure-sensitive adhesive according to claim 1, characterized in that: The crosslinking agent is selected from multifunctional acrylate monomers.

6. The skin bonding pressure-sensitive adhesive according to claim 5, characterized in that: The multifunctional acrylate monomer includes at least one of 1,6-hexanediol diacrylate, ethoxylated trimethylolpropane triacrylate and dipentaerythritol hexaacrylate.

7. A pressure-sensitive adhesive product, characterized in that: It comprises a base layer and an adhesive layer arranged on at least one side of the base layer; the adhesive layer comprises the pressure-sensitive adhesive according to any one of claims 1 to 6.

Images