Pressure-sensitive hot melt adhesive for medical tape and preparation method thereof

Abstract

The present invention relates to the field of hot melt adhesive technology, in particular to the field of IPC C09J7, and more specifically to a pressure-sensitive hot melt adhesive for medical tape and a preparation method thereof. The pressure-sensitive hot melt adhesive for medical tape, in parts by weight, comprises: 20-45 parts of block copolymer, 20-55 parts of tackifying resin, 5-25 parts of aliphatic mineral oil, and 0.05-2 parts of antioxidant. The pressure-sensitive hot melt adhesive for medical tape has high shear strength, tack retention and weather resistance, as well as a certain tack retention force, and does not cause allergic reactions with the skin.

Description

Technical Field

[0001] The present invention relates to the technical field of hot melt adhesives, in particular to the field of IPC C09J7, and more specifically to a pressure-sensitive hot melt adhesive for medical tape and a preparation method thereof. Background Art

[0002] Pressure-sensitive hot-melt adhesive is a kind of adhesive that is applied to the adherend in a molten state, and can be bonded by pressing with fingers after cooling and solidification. Due to its advantages such as environmental protection, solvent-free and pollution-free, and easy to use, it is widely used in tapes, packaging, construction, decoration, etc., and can even be used in the medical and health industry. However, pressure-sensitive hot-melt adhesives for medical labels and tapes have higher requirements on the performance of the adhesive, requiring not only high shear strength, lasting adhesion and weather resistance, but also a certain degree of lasting adhesion and no allergic reaction to the skin.

[0003] In the prior art, the patent application document with application publication number CN105086893A discloses a medical hot melt adhesive and a preparation method thereof, wherein the raw materials include: a graft product of SIS and PEG, cyclohexane oil, an antioxidant, a hydrogenated petroleum resin, and SAP. A medical hot melt adhesive with good sweat resistance and good air permeability is prepared, but it has a slight tingling sensation when peeled and has a low peel strength.

[0004] The patent application document with application publication number CN103740305A discloses a medical hot melt adhesive and a preparation method thereof. The hot melt adhesive has good bonding effect and flexibility when used at low temperatures, but its peel strength and holding force performance are poor.

[0005] Styrene-based thermoplastic elastomers have a unique two-phase structure and are compatible with all types of tackifying resins. The pressure-sensitive hot melt adhesive produced thereby has both the properties of a hot melt adhesive and a pressure-sensitive adhesive, but it itself is not sticky. Therefore, the present application prepares a pressure-sensitive hot melt adhesive for medical tape based on styrene-based thermoplastic elastomer. The pressure-sensitive hot melt adhesive has high shear strength, long-lasting adhesion and weather resistance, as well as a certain degree of long-lasting adhesion and does not cause allergic reactions to the skin. Summary of the invention

[0006] In order to solve the above problems, the first aspect of the present invention provides a pressure-sensitive hot melt adhesive for medical tape. The raw materials for preparation include, by weight: 20-45 parts of block copolymer, 20-55 parts of tackifying resin, 5-25 parts of aliphatic mineral oil, and 0.05-2 parts of antioxidant.

[0007] Preferably, the block copolymer is selected from one or more of styrene-isoprene-styrene block copolymer (SIS block copolymer), styrene-butadiene block copolymer, styrene-butadiene-styrene block copolymer (SBS block copolymer), styrene-butadiene-3-chloropropylene block copolymer; further preferably, it is SIS block copolymer.

[0008] Preferably, the block ratio (S / I) of the block copolymer is 15 / 85-30 / 70, and the diblock (SI) content is 0-50%; further preferably, the block ratio S / I of the block copolymer is 15 / 85, and the diblock SI content is 16.7%.

[0009] In some preferred embodiments, the block copolymer may be commercially available, such as YH 1106 produced by Hunan Yuehua Chemical Industry Co., Ltd.

[0010] In some preferred embodiments, the block copolymer is selected from SIS block copolymer, in which both ends of SIS are hard plastic phases and the middle is a soft rubber phase, so it has both thermoplasticity and solubility, flexibility and elasticity, and has multiple side methyl structures, which can provide strong adhesion for pressure-sensitive hot melt adhesive. Ordinary medical pressure-sensitive hot melt adhesive has low viscosity and is easy to fall off from the skin. The applicant unexpectedly found that the use of SIS block copolymers with a block ratio S / I of 15 / 85-30 / 70 and a diblock SI content of 0-50% as block polymers can enhance the viscosity and toughness of medical pressure-sensitive hot melt adhesives. This is because the polystyrene phase (S phase) in the SIS block copolymer is a hard segment and the polyisoprene phase (I phase) is a soft segment. When the block ratio increases, the S phase increases and the physical cross-linking sites increase, thereby increasing the cohesion of the pressure-sensitive hot melt adhesive, but reducing its viscosity. When the block ratio decreases and the I phase increases, the cross-linking sites will be reduced, affecting the cross-linking degree of the polymer and the strength of the medical pressure-sensitive hot melt adhesive. The diblock SI has certain "network defects" in its microstructure, and an increase in its content will lead to an increase in the viscosity of the pressure-sensitive hot melt adhesive, but The reduction of cohesion will lead to a decrease in its sustained adhesion, and the reduction of diblock SI will reduce the viscosity of the system. When SIS block copolymers with a block ratio S / I of 15 / 85-30 / 70 and a diblock SI content of 0-50% are selected as block polymers, the viscosity of the medical pressure-sensitive hot melt adhesive can be increased while its sustained adhesion can be increased. However, the SIS block copolymer itself is not sticky, so a certain amount of tackifying resin, aliphatic mineral oil and antioxidant need to be added to increase the fluidity and adhesion of the medical pressure-sensitive hot melt adhesive.

[0011] Preferably, the tackifying resin is selected from one or more of rosin resin, petroleum resin, terpene resin, terpene-phenolic resin; more preferably, it is petroleum resin.

[0012] Preferably, the petroleum resin is selected from one or more of aliphatic petroleum resin and aromatic petroleum resin; further preferably, it is aliphatic petroleum resin.

[0013] Preferably, the aliphatic petroleum resin is a hydrogenated aliphatic petroleum resin.

[0014] Preferably, the softening point of the hydrogenated aliphatic petroleum resin is 95-110° C., and the yellowness index is 3.0-9.5; further preferably, the softening point is 90-105° C., and the yellowness index is 4.5-6.9.

[0015] In some preferred embodiments, the hydrogenated aliphatic petroleum resin may be commercially available, such as H5-1000 produced by Zhejiang Henghe Petrochemical Group Co., Ltd.

[0016] Pressure-sensitive hot melt adhesives for medical tapes have high requirements for adhesive performance. They need to have a certain degree of stickiness and no residue when torn off. The applicant found that the use of hydrogenated aliphatic petroleum resin as a tackifying resin can not only improve the bonding strength and peel strength of medical pressure-sensitive hot melt adhesives, but also reduce melt viscosity and reduce residue. This may be because aliphatic petroleum resins have low solubility parameters, low polarity, and excellent compatibility with SIS, which can improve the viscosity of medical pressure-sensitive hot melt adhesives. In addition, hydrogenating aliphatic petroleum resins to convert unsaturated hydrocarbons into saturated hydrocarbons can improve the weather resistance of medical pressure-sensitive hot melt adhesives. The applicant unexpectedly discovered that the use of hydrogenated aliphatic petroleum resin with a softening point of 95-110°C and a yellowness index of 3.0-9.5 can also improve the cohesion of medical pressure-sensitive hot melt adhesives. This is because it has a high softening point and exists in an aggregated state in the system, thereby being able to increase the viscosity of the medical pressure-sensitive hot melt adhesive while also increasing cohesion, having good weather resistance and less residue. In addition, hydrogenated aliphatic petroleum resins are cheap, which can effectively reduce production costs and greatly improve economic benefits.

[0017] Preferably, the weight ratio of the block copolymer to the tackifying resin is 1:(0.5-2); further preferably, it is 1:1.

[0018] Pressure-sensitive hot melt adhesives are used in the medical field. It is not enough to have high viscosity alone. They also need to have a certain holding force. The applicant unexpectedly discovered that when the weight ratio of the block copolymer to the tackifying resin is 1: (0.5-2), the prepared medical pressure-sensitive hot melt adhesive not only has a high peel strength, but also has a high holding force. This may be due to the addition of increasing or decreasing values, which can improve the wettability and cohesion of the pressure-sensitive hot melt adhesive, so that the medical pressure-sensitive hot melt adhesive can well infiltrate the adherend, thereby improving the peel strength and having a high holding force, so that it can be well used in the medical field. However, with the increase in the amount of tackifying resin, it becomes the main phase in the system, which makes the hardness of the pressure-sensitive hot melt adhesive too large, and it is not easy to wet the surface of the adherend, which will reduce the peel strength, and the low SIS content will reduce the cross-linking effect, thereby reducing the intermolecular force and reducing the holding force.

[0019] Preferably, the aliphatic mineral oil is selected from one or more of aromatic rubber oil, paraffin rubber oil and cycloalkyl rubber oil; more preferably, it is cycloalkyl rubber oil.

[0020] Preferably, the cycloalkyl rubber oil has a kinematic viscosity of 9-11 mm at 100°C. 2 / s; further preferably, 10.29mm 2 / s.

[0021] In some preferred embodiments, the cycloalkyl rubber oil may be commercially available, such as KN4010 produced by Jinan Shanhai Chemical Technology Co., Ltd.

[0022] The applicant unexpectedly discovered that adding a certain amount of cycloalkyl rubber oil as aliphatic mineral oil can improve the adhesion of medical pressure-sensitive hot melt adhesives, reduce the melt viscosity of medical pressure-sensitive hot melt adhesives, and further reduce the residue of medical pressure-sensitive hot melt adhesives. This may be because cycloalkyl rubber oil not only has the characteristics of paraffin base, but also has the characteristics of aromatic base, and has good compatibility with block copolymers and tackifying resins. It can reduce the intermolecular force of block polymers to improve the activity of molecular chains, thereby increasing the flexibility of medical pressure-sensitive hot melt adhesives, improving its processing performance, reducing the residue of medical pressure-sensitive hot melt adhesives, and appropriately reducing costs. Pressure-sensitive hot melt adhesives are used in the fields of medical tapes, labels, etc., and are required to be non-toxic and harmless, and will not cause skin allergies. Cycloalkyl rubber oil is non-toxic and non-polluting. When the mass ratio of cycloalkyl rubber oil to block copolymers is 1: (1-5), it can not only improve the performance of medical pressure-sensitive hot melt adhesives, but also be non-toxic and non-sensitizing, and have good biocompatibility.

[0023] Preferably, the antioxidant is selected from one or more of hindered phenol antioxidants, phosphite antioxidants, thioether antioxidants, and hydroxylamine antioxidants; more preferably, it is a hindered phenol antioxidant.

[0024] Preferably, the melting point of the hindered phenol antioxidant is 100-150°C; more preferably, it is 110-125°C.

[0025] In some preferred embodiments, the antioxidant may be commercially available, such as the antioxidant produced by BASF Corporation of the United States. 1010.

[0026] A second aspect of the present invention provides a method for preparing the pressure-sensitive hot melt adhesive as described above, comprising the following steps:

[0027] The tackifying resin, aliphatic mineral oil and antioxidant are mixed and heated to 120-180°C, stirred until the solution is homogeneous and transparent, and then the block polymer is added and stirred continuously until the solution is homogeneous and transparent.

[0028] Beneficial effects:

[0029] 1. By selecting a SIS block copolymer with a block ratio S / I of 15 / 85-30 / 70 and a diblock SI content of 0-50% as a block polymer, the viscosity of the medical pressure-sensitive hot melt adhesive can be increased while increasing its holding power.

[0030] 2. Select hydrogenated aliphatic petroleum resin with a softening point of 95-110℃ and a yellowness index of 3.0-9.5, which can improve the viscosity of medical pressure-sensitive hot melt adhesive while also improving cohesion, good weather resistance and less residue, and can effectively reduce production costs, greatly improving economic benefits.

[0031] 3. The medical pressure-sensitive hot melt adhesive prepared by selecting a block copolymer and a tackifying resin in a weight ratio of 1: (0.5-2) has not only high peel strength but also high holding force.

[0032] 4. Selecting cycloalkyl rubber oil with a weight ratio of 1: (1-5) to block copolymer as aliphatic mineral oil can improve the adhesion of medical pressure-sensitive hot melt adhesive, reduce the melt viscosity of medical pressure-sensitive hot melt adhesive, further reduce the residual medical pressure-sensitive hot melt adhesive, and the raw material is non-toxic and non-sensitizing, and has good biocompatibility.

[0033] 5. The pressure-sensitive hot-melt adhesive for medical tape prepared by the present invention is not only suitable for medical fields such as medical labels and tapes, but also suitable for women's products, packaging, shoemaking, decoration and other fields. DETAILED DESCRIPTION

[0034] Example

[0035] Example 1

[0036] Example 1 provides a pressure-sensitive hot melt adhesive for medical tape, and its preparation raw materials include, by weight: 35 parts of block copolymer, 35 parts of tackifying resin, 15 parts of aliphatic mineral oil, and 0.1 parts of antioxidant.

[0037] The block copolymer is a styrene-isoprene-styrene block copolymer (SIS block copolymer).

[0038] The block copolymer had a block ratio (S / I) of 15 / 85 and a diblock (SI) content of 16.7%.

[0039] The block copolymer was purchased from a supplier, Hunan Yuehua Chemical Industry Co., Ltd., and produced YH 1106.

[0040] The tackifying resin is petroleum resin.

[0041] The petroleum resin is an aliphatic petroleum resin.

[0042] The aliphatic petroleum resin is a hydrogenated aliphatic petroleum resin.

[0043] The softening point of the hydrogenated aliphatic petroleum resin is 90-105° C., and the yellowness index is 4.5-6.9.

[0044] The hydrogenated aliphatic petroleum resin was purchased from a supplier, Zhejiang Henghe Petrochemical Group Co., Ltd., and was produced as H5-1000.

[0045] The aliphatic mineral oil is cycloalkyl rubber oil.

[0046] The kinematic viscosity of the naphthenic rubber oil at 100°C is 10.29 mm 2 / s.

[0047] The cycloalkyl rubber oil was purchased from a supplier, Jinan Shanhai Chemical Technology Co., Ltd., and produced KN4010.

[0048] The antioxidant is a hindered phenol antioxidant.

[0049] The melting point of the hindered phenol antioxidant is 110-125°C.

[0050] The antioxidant was purchased from BASF Corporation in the United States. 1010.

[0051] A method for preparing a pressure-sensitive hot melt adhesive for medical tape comprises the following steps:

[0052] The tackifying resin, aliphatic mineral oil and antioxidant are mixed and heated to 150° C., and stirred until the solution is homogeneous and transparent. Then, the block polymer is added and stirred continuously until the solution is homogeneous and transparent.

[0053] Example 2

[0054] Example 2 provides a pressure-sensitive hot melt adhesive for medical tape. The specific implementation method is the same as that of Example 1, except that: 20 parts of block copolymer, 20 parts of tackifying resin, 5 parts of aliphatic mineral oil, and 0.05 parts of antioxidant.

[0055] Example 3

[0056] Example 3 provides a pressure-sensitive hot melt adhesive for medical tape. The specific implementation method is the same as that of Example 1, except that: 45 parts of block copolymer, 55 parts of tackifying resin, 25 parts of aliphatic mineral oil, and 2 parts of antioxidant.

[0057] Example 4

[0058] Example 4 provides a pressure-sensitive hot melt adhesive for medical tape. The specific implementation method is the same as that of Example 1, except that its preparation raw materials include: 15 parts of block copolymer, 45 parts of tackifying resin, 15 parts of aliphatic mineral oil, and 0.1 parts of antioxidant.

[0059] Example 5

[0060] Example 5 provides a pressure-sensitive hot melt adhesive for medical tape. The specific implementation method is the same as that of Example 1, except that the aliphatic mineral oil is an aromatic rubber oil.

[0061] The aliphatic mineral oil was purchased from the aromatic rubber oil produced by Hebei Jiale Petroleum Technology Co., Ltd.

[0062] Performance Testing Methods

[0063] The medical tape prepared in Example 1-5 was evenly coated on the anti-adhesive layer with the pressure-sensitive hot melt adhesive at a coating temperature of 130° C. and a coating thickness of 80 μm. After cooling to 25° C., the backing material was pressed to obtain the medical tape.

[0064] 1. Peel strength

[0065] The peel strength of the medical tapes prepared in Examples 1-5 was measured using the national standard GB / T 2792-2014, and the results are recorded in Table 1.

[0066] 2. Residue test

[0067] The medical tapes prepared in Examples 1-5 were tested for peel strength using the national standard GB / T 2792-2014, and the adhesive residue on the surface of the steel plate was visually inspected. The tapes were qualified if there was no residue. The results are recorded in Table 1.

[0068] 3. Maintaining stickiness

[0069] The medical tapes prepared in Examples 1-5 were tested for their adhesive properties using the national standard GB / T 4851-1998. The results are recorded in Table 1.

[0070] 4. Biocompatibility

[0071] For the medical tapes prepared in Examples 1-5, the cytotoxicity test of the medical tapes was carried out using the ISO 10993-5:2009 method, and the 100% sample extract was compared with the blank control. Cell viability exceeding 80% was considered to have passed the biocompatibility test. The results are recorded in Table 1.

[0072] Table 1

[0073]

Claims

1. A pressure-sensitive hot melt adhesive for medical tape, It is characterized in that The raw materials for its preparation include, by weight: 35 parts of block copolymer, 35 parts of tackifying resin, 15 parts of aliphatic mineral oil, and 0.1 parts of antioxidant; The block copolymer is a styrene-isoprene-styrene block copolymer; the block ratio (S / I) of the block copolymer is 15 / 85, and the diblock (SI) content is 16.7%; The tackifying resin is a hydrogenated aliphatic petroleum resin, the softening point of the hydrogenated aliphatic petroleum resin is 90-105° C., and the yellowness index is 4.5-6.9; The aliphatic mineral oil is a cycloalkyl rubber oil; the kinematic viscosity of the cycloalkyl rubber oil at 100°C is 10.29 mm 2 / s; The antioxidant is a hindered phenol antioxidant; the melting point of the hindered phenol antioxidant is 110-125°C.

2. A pressure-sensitive hot melt adhesive for medical tape, It is characterized in that The raw materials for its preparation include, by weight: 20 parts of block copolymer, 20 parts of tackifying resin, 5 parts of aliphatic mineral oil, and 0.05 parts of antioxidant; The block copolymer is a styrene-isoprene-styrene block copolymer; the block ratio (S / I) of the block copolymer is 15 / 85, and the diblock (SI) content is 16.7%; The tackifying resin is a hydrogenated aliphatic petroleum resin, the softening point of the hydrogenated aliphatic petroleum resin is 90-105° C., and the yellowness index is 4.5-6.9; The aliphatic mineral oil is a cycloalkyl rubber oil; the kinematic viscosity of the cycloalkyl rubber oil at 100°C is 10.29 mm 2 / s; The antioxidant is a hindered phenol antioxidant; the melting point of the hindered phenol antioxidant is 110-125°C.

3. A pressure-sensitive hot melt adhesive for medical tape, It is characterized in that The raw materials for its preparation include, by weight: 45 parts of block copolymer, 55 parts of tackifying resin, 25 parts of aliphatic mineral oil, and 2 parts of antioxidant; The block copolymer is a styrene-isoprene-styrene block copolymer; the block ratio (S / I) of the block copolymer is 15 / 85, and the diblock (SI) content is 16.7%; The tackifying resin is a hydrogenated aliphatic petroleum resin, the softening point of the hydrogenated aliphatic petroleum resin is 90-105° C., and the yellowness index is 4.5-6.9; The aliphatic mineral oil is a cycloalkyl rubber oil; the kinematic viscosity of the cycloalkyl rubber oil at 100°C is 10.29 mm 2 / s; The antioxidant is a hindered phenol antioxidant; the melting point of the hindered phenol antioxidant is 110-125°C.

4. A method for preparing a pressure-sensitive hot melt adhesive for medical tape according to any one of claims 1 to 3, It is characterized in that The following steps are involved: Mix the tackifying resin, aliphatic mineral oil and antioxidant and heat to 120-180°C, stir until the solution is homogeneous and transparent, add the block polymer and continue stirring until the solution is homogeneous and transparent, and cool to 20-30°C to obtain the product.

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