Hot-melt pressure-sensitive adhesive suitable for medical adhesive tape and preparation method of hot-melt pressure-sensitive adhesive

Abstract

The invention relates to the field of adhesives, in particular to the field of C09J155 / 00, and particularly relates to a hot-melt pressure-sensitive adhesive suitable for a medical adhesive tape and a preparation method of the hot-melt pressure-sensitive adhesive. The hot-melt pressure-sensitive adhesive suitable for the medical adhesive tape is prepared from the following raw materials in parts by mass: 30-40 parts of a main polymer, 30-50 parts of tackifying resin, 5-10 parts of a tackifier, 10-30 parts of rubber oil and 0.1-3 parts of a functional aid, wherein the main polymer comprises linear SIS and star SIS; the hot-melt pressure-sensitive adhesive provided by the invention is excellent in initial adhesion and persistent adhesion performance, is peelable, and is especially suitable for being applied to medical adhesive tapes, and the raw materials of all the components are nontoxic and harmless.

Description

Technical Field

[0001] The invention relates to the field of adhesives, in particular to the field of C09J155 / 00, and specifically to a hot-melt pressure-sensitive adhesive suitable for medical tape and a preparation method thereof. Background Art

[0002] Hot melt pressure sensitive adhesive is a common adhesive, which is mainly made by mixing synthetic rubber, resin and rubber oil under heating conditions. The finished hot melt pressure sensitive adhesive can be heated into a molten state and coated on different substrates such as cotton paper, medical non-woven fabrics or engineering plastic films to make tapes for different purposes.

[0003] Medical tape is a common medical auxiliary device similar to a "band-aid" and is often used for wound dressing. Its main raw materials include medical non-woven fabrics and medical adhesives. Medical adhesives usually need to have low allergy, good air permeability, high initial adhesion, high sustained adhesion and other properties, and also need to be easy to apply. Medical adhesives used in daily medical tapes also need to have certain peelability. At present, some medical tapes on the market have defects such as easy detachment at joints and short service life due to their general sustained adhesion during use.

[0004] Prior art CN104056296B discloses a medical tape, the raw materials for its preparation mainly include: 2-3 parts of methyl methacrylate, 20-30 parts of organic silicone latex, 80-100 parts of acrylic pressure-sensitive adhesive and non-woven fabric; those skilled in the art know that acrylic pressure-sensitive adhesive is better than hot-melt pressure-sensitive adhesive in terms of weather resistance. The medical adhesive prepared with hot-melt pressure-sensitive adhesive is attached to non-woven fabric for aging test. At 60°C, there will be obvious wrinkling, while the acrylic pressure-sensitive adhesive tape will not wrinkle. However, at the same time, the initial adhesion and lasting adhesion of hot-melt pressure-sensitive adhesive are relatively better. Specifically combined with the application of medical tape, the use temperature of medical tape is generally not too high, and it is often used at room temperature. Therefore, there is no need to consider the weather resistance problem too much. In contrast, hot-melt pressure-sensitive adhesive is obviously more suitable for use in medical tape. Based on this, the present invention aims to develop a hot-melt pressure-sensitive adhesive that can be bonded to the skin and can be bonded again after removal, which is suitable for medical tape. Summary of the invention

[0005] In order to solve the above technical problems, the first aspect of the present invention provides a hot melt pressure-sensitive adhesive suitable for medical tape, the raw materials for its preparation, calculated by weight, include: 30-40 parts of a main polymer, 30-50 parts of a tackifying resin, 5-10 parts of a tackifier, 10-30 parts of rubber oil, and 0.1-3 parts of a functional additive.

[0006] Preferably, the main polymer includes: SBS, SIS, SEBS, SEPS or a combination of several thereof.

[0007] More preferably, the host polymer is SIS.

[0008] Preferably, the S:I block ratio of the SIS is (15-20):(80-85).

[0009] Preferably, the viscosity of the SIS at 25° C. and 25% toluene solution is 500-1000 mPa·s (the viscosity at 25° C. and 25% toluene solution represents that SIS is used as solute and toluene is used as solvent, and SIS is dissolved in toluene to prepare a solution with a mass concentration of 25%).

[0010] Preferably, the SIS includes at least two of: linear SIS, coupled linear SIS, and star SIS.

[0011] Further preferably, the SIS includes: linear SIS and star SIS, with a mass ratio of 1:(1-1.5); as an implementable case, the S:I block ratio of the linear SIS is 15:85, the viscosity at 25°C, 25% toluene solution is 900 mPa·s, and the model is YH-1106; the S:I block ratio of the star SIS is 18:82, the viscosity at 25°C, 25% toluene solution is 500 mPa·s, and the model is YH-4016.

[0012] The present invention preferably uses SIS as the main polymer. SIS has good cohesion, which is mainly due to the combined effect of the styrene hard segment and the isoprene soft segment in its molecular structure. The hard segment provides physical crosslinking points to enhance cohesion; the soft segment gives the hot melt pressure-sensitive adhesive good elasticity and adhesion, so SIS has excellent adhesion performance and can form a firm bond with medical non-woven fabrics and skin; by adjusting the block ratio S:I of styrene to isoprene in SIS, the initial tack, sustained tack, melt viscosity and softening point of the hot melt pressure-sensitive adhesive can be significantly affected; as the block ratio S:I increases, the sustained tack of the hot melt pressure-sensitive adhesive increases, the softening point increases, but the initial tack may be somewhat Therefore, in the present invention, the preferred S:I block ratio is (15-20): (80-85), and the viscosity of SIS in 25% toluene solution at 25°C is 500-1000mPa·s, which can achieve a balance between initial adhesion and sustained adhesion. In addition, in order to further improve the bonding strength, the present invention preferably compounds linear SIS and star-shaped SIS, the star-shaped structure has better fluidity or dispersibility, and the linear structure has better mechanical property stability; after compounding, the hot melt pressure-sensitive adhesive can have more balanced physical properties, and the chemical stability of the hot melt pressure-sensitive adhesive can be optimized by adjusting the ratio of linear and star-shaped molecules, thereby reducing performance fluctuations caused by a single structure.

[0013] Preferably, the tackifying resin comprises a first tackifying resin and a second tackifying resin, and the mass ratio of the two components is (5-10):(1-3); wherein the first tackifying resin and the second tackifying resin are both one of petroleum resin, phenolic resin, rosin resin, and coumarone resin.

[0014] Further preferably, the first tackifying resin and the second tackifying resin are both petroleum resins.

[0015] Preferably, the petroleum resin includes: one of C5 petroleum resin, hydrogenated C5 petroleum resin, C5 / C9 copolymerized petroleum resin, C9 petroleum resin, hydrogenated C9 petroleum resin, and dicyclopentadiene resin.

[0016] Further preferably, the first tackifying resin and the second tackifying resin are both hydrogenated C5 petroleum resins.

[0017] More preferably, the first tackifying resin is Wingtack10, and the second tackifying resin is H5-1000.

[0018] Hydrogenated C5 petroleum resin has good compatibility with SIS, which makes it an effective tackifying resin in hot melt pressure-sensitive adhesives to improve the bonding strength and adhesion of hot melt pressure-sensitive adhesives. When used in medical tapes, hydrogenated C5 petroleum resin has a wetting effect on the adhered surface and can enhance the adhesion of hot melt pressure-sensitive adhesives through surface diffusion. In the present invention, two different grades of petroleum resins are selected as tackifying resins, wherein the softening point of H5-1000 is about 100° C. The petroleum resin with a high softening point can improve the adhesive strength of the adhesive, making the bonding more firm and reliable, while ensuring that the adhesive has high hardness and wear resistance. However, if the softening point is too high, it may require higher temperature and pressure to soften and shape it during processing, which increases the difficulty and cost of processing. Therefore, the inventors added Wingtack10 with a softening point of 10° C. The low softening point of Wingtack10 can reduce processing time and energy consumption, reduce the exudation of rubber oil, improve production efficiency, achieve better coating performance and adhesive performance, and thus the hot melt pressure-sensitive adhesive has better adhesion and durability. However, the mass ratio of Wingtack10 to H5-1000 needs to be limited to (5-10): (1-3), otherwise it is difficult for the hot melt pressure-sensitive adhesive to achieve an optimal balance between processing performance and adhesive performance.

[0019] Preferably, the tackifier includes one or more of polybutadiene, polybutylene and polyisobutylene.

[0020] Further preferably, the tackifier is polyisobutylene, and the number average molecular weight of polyisobutylene is 350-1000; as an implementable case, the number average molecular weight of polyisobutylene is 950, and the brand is Korea Dalin PB950.

[0021] Polyisobutylene has good adhesion and bonding ability, which can greatly improve the adhesive performance and bonding strength of the hot melt pressure-sensitive adhesive, so that the hot melt pressure-sensitive adhesive can adhere more firmly to medical non-woven fabrics and skin. However, the number average molecular weight of polyisobutylene should not exceed 1000. If the number average molecular weight of polyisobutylene is too high, the bulk viscosity of the hot melt pressure-sensitive adhesive may increase significantly, hindering the flow and wetting properties of the hot melt pressure-sensitive adhesive during the coating process, thereby causing uneven coating and affecting the bonding effect.

[0022] Preferably, the rubber oil is naphthenic oil and / or white mineral oil.

[0023] Further preferably, the rubber oil is cycloparaffinic oil, and the kinematic viscosity of cycloparaffinic oil at 40° C. is 120-140 cSt; as an implementable case, the cycloparaffinic oil is KN4010, purchased from PetroChina.

[0024] The present invention does not further limit the functional additives. If the aging resistance of the hot melt pressure-sensitive adhesive needs to be improved, an antioxidant can be added; if the UV protection of the hot melt pressure-sensitive adhesive needs to be improved, an anti-UV agent can be added; the specific requirements can be flexibly adjusted according to actual production requirements, and no further details will be given here.

[0025] The second aspect of the present invention provides a method for preparing a hot melt pressure-sensitive adhesive suitable for medical tape, comprising:

[0026] S1. Put the rubber oil into a stirring kettle, heat it to 100-120℃ and stir it, then add the main polymer and functional additives, and heat and stir them evenly at 130-140℃;

[0027] S2, add the first tackifying resin, then add the tackifier and the second tackifying resin, evacuate and continue stirring for 30-40 minutes, extrude, and obtain the material.

[0028] Beneficial Effects

[0029] (i) The hot melt pressure-sensitive adhesive prepared by the present invention using SIS and petroleum resin as the main raw materials has better bonding performance and peelability than acrylic glue, and is more suitable for application in medical tapes.

[0030] (ii) The compounding of two SISs with specific viscosities and block ratios in the present invention is beneficial to the bonding performance and mechanical stability of the hot melt pressure-sensitive adhesive.

[0031] (III) In order to further improve the bonding performance of the hot melt pressure-sensitive adhesive in the present invention, two hydrogenated C5 petroleum resins with different softening points are preferably compounded, which is beneficial for the adhesive to achieve the optimal balance between processing performance and sustained adhesion performance; in addition, the compounding of hydrogenated C5 petroleum resin and SIS can effectively reduce the occurrence of rubber oil seepage and increase the service life of the product.

[0032] (IV) The present invention selects polyisobutylene with a number average molecular weight of less than 1000, which can ensure the fluidity and wettability of the hot melt pressure-sensitive adhesive and further improve the bonding performance of the product.

[0033] (V) The raw materials for preparing the hot melt pressure-sensitive adhesive in the present invention are from a wide range of sources, and the preparation method is relatively simple. It can be prepared by simply adding the raw material components into the reaction system in a certain order at a certain temperature. No organic solvent is required, which reduces VOCs emissions in the production workshop and makes the process more environmentally friendly. DETAILED DESCRIPTION

[0034] Example 1

[0035] In the first aspect of this example, a hot melt pressure-sensitive adhesive suitable for medical tape is provided, and the raw materials for its preparation include, by weight: 35 parts of a main polymer, 35 parts of a tackifying resin, 10 parts of a tackifier, 19.5 parts of rubber oil, and 0.5 parts of a functional additive.

[0036] The main polymer is SIS, model YH-1106 and YH-4016, the mass ratio of the two components is 1:1, both purchased from Yueyang Petrochemical; YH-1106 is a linear SIS, the S:I block ratio is 15:85, and the viscosity is 900mPa·s at 25°C and 25% toluene solution; YH-4016 is a star SIS, the S:I block ratio is 18:82; the viscosity is 500mPa·s at 25°C and 25% toluene solution.

[0037] The tackifying resin includes a first tackifying resin and a second tackifying resin in a mass ratio of 5:2; the first tackifying resin and the second tackifying resin are both hydrogenated C5 petroleum resins, wherein the first tackifying resin is brand H5-1000, purchased from Henghe Materials; the second tackifying resin is brand Wingtack10, purchased from Crayville.

[0038] The tackifier is polyisobutylene with a number average molecular weight of 950 and a brand name of Dalin PB950 from Korea.

[0039] The rubber oil is naphthenic oil with a brand name of KN4010 and a kinematic viscosity of 140 cSt at 40° C., purchased from PetroChina.

[0040] The functional additive is antioxidant 1010, purchased from Lionlon.

[0041] The second aspect of this example provides a method for preparing a hot melt pressure-sensitive adhesive suitable for medical tape, comprising:

[0042] S1. Put the rubber oil into a stirring kettle, heat it to 120℃ and stir it, then add the main polymer and functional additives, and stir them evenly at 140℃;

[0043] S2, add the first tackifying resin, then add the tackifier and the second tackifying resin, evacuate and continue stirring for 30 minutes, extrude, and obtain the material.

[0044] Comparative Example 1

[0045] In the first aspect of this example, a hot melt pressure-sensitive adhesive suitable for medical tape is provided, and the raw materials for its preparation include, by weight: 35 parts of a main polymer, 35 parts of a tackifying resin, 10 parts of a tackifier, 19.5 parts of rubber oil, and 0.5 parts of a functional additive.

[0046] The main polymer is SIS, the models are Jinhai 8152 and YH-4016, the mass ratio of the two components is 1:1, YH-4016 is purchased from Yueyang Petrochemical, and Jinhai 8152 is purchased from Hunan Jinhai Technology Co., Ltd.

[0047] The tackifying resin includes a first tackifying resin and a second tackifying resin in a mass ratio of 5:2; the first tackifying resin and the second tackifying resin are both hydrogenated C5 petroleum resins, wherein the first tackifying resin is brand H5-1000, purchased from Henghe Materials; the second tackifying resin is brand Wingtack10, purchased from Crayville.

[0048] The tackifier is polyisobutylene with a number average molecular weight of 950 and a brand name of Dalin PB950 from Korea.

[0049] The rubber oil is naphthenic oil with a brand name of KN4010 and a kinematic viscosity of 140 cSt at 40° C., purchased from PetroChina.

[0050] The functional additive is antioxidant 1010, purchased from Lionlon.

[0051] The second aspect of this example provides a method for preparing a hot melt pressure-sensitive adhesive suitable for medical tape, comprising:

[0052] S1. Put the rubber oil into a stirring kettle, heat it to 120°C and stir it, then add the main polymer and functional additives, and stir them evenly at 140°C;

[0053] S2, add the first tackifying resin, then add the tackifier and the second tackifying resin, evacuate and continue stirring for 30 minutes, extrude, and obtain the material.

[0054] In the process of preparing the product in this example, the melt viscosity increased sharply, which affected the cohesion of the hot melt pressure-sensitive adhesive and the requirements of the subsequent coating. Jinhai 8152 was used, and its melt viscosity at 140°C was 24000mPa·s; while Example 1 used YH-1106, and its melt viscosity at 140°C was 18000cps.

[0055] Performance Evaluation

[0056] Test method: The substrate is a PET film with a thickness of 50 μm and the glue coating amount is 30 ± 5 gsm.

[0057] 180° peel strength: Refer to standard GB / T 2792-2014 Test method for peel strength of adhesive tape.

[0058] Ring tack: Refer to standard GB / T 31125-2014 Adhesive tape initial tack test method (ring method).

[0059] Stickiness: Refer to the test method for stickiness of adhesive tapes in standard GB / T 4851-2014.

[0060] The test results are shown in Table 1. The hot melt pressure-sensitive adhesive prepared in Comparative Example 1 cannot be normally coated due to its high viscosity and is not very practical, so the test object is Example 1.

[0061] Table 1

[0062] Test items Example 1 <![CDATA[Ring tack N / in 2 > 36 180° peel force N / in 35 Stickiness hrs / 1kg ＞72h

Claims

1. A hot melt pressure sensitive adhesive suitable for medical tape, characterized in that: The raw materials for preparation include, by weight: 30-40 parts of a main polymer, 30-50 parts of a tackifying resin, 5-10 parts of a tackifier, 10-30 parts of rubber oil, and 0.1-3 parts of a functional additive; The tackifying resin comprises a first tackifying resin and a second tackifying resin, and the mass ratio of the two components is (5-10): (1-3).

2. The hot melt pressure sensitive adhesive suitable for medical tape according to claim 1, characterized in that: The main polymer includes: one or a combination of SBS, SIS, SEBS and SEPS.

3. The hot melt pressure sensitive adhesive suitable for medical tape according to claim 2, characterized in that: The S:I block ratio of the SIS is (15-20):(80-85).

4. The hot melt pressure sensitive adhesive suitable for medical tape according to claim 2, characterized in that: The viscosity of the SIS at 25° C. and 25% toluene solution is 500-1000 mPa·s.

5. The hot melt pressure sensitive adhesive suitable for medical tape according to claim 2, characterized in that: The SIS includes at least two types: linear SIS, coupled linear SIS, and star SIS.

6. The hot melt pressure sensitive adhesive suitable for medical tape according to any one of claims 1 to 5, characterized in that: The first tackifying resin and the second tackifying resin are both one of petroleum resin, phenolic resin, rosin resin and coumarone resin.

7. The hot melt pressure sensitive adhesive suitable for medical tape according to claim 6, characterized in that: The petroleum resin includes one of: C5 petroleum resin, hydrogenated C5 petroleum resin, C5 / C9 copolymerized petroleum resin, C9 petroleum resin, hydrogenated C9 petroleum resin and dicyclopentadiene resin.

8. The hot melt pressure sensitive adhesive suitable for medical tape according to claim 1, characterized in that: The tackifier includes one or more of polybutadiene, polybutylene and polyisobutylene.

9. The hot melt pressure sensitive adhesive suitable for medical tape according to claim 8, characterized in that: The number average molecular weight of the polyisobutylene is 350-1000.

10. A method for preparing a hot melt pressure sensitive adhesive suitable for medical tape according to any one of claims 1 to 9, characterized in that: include: S1. Put the rubber oil into a stirring kettle, heat it to 100-120℃ and stir it, then add the main polymer and functional additives, and heat and stir them evenly at 130-140℃; S2, add the first tackifying resin, then add the tackifier and the second tackifying resin, evacuate and continue stirring for 30-40 minutes, extrude, and obtain the material.