SIS pressure-sensitive hot melt adhesive green cleaning agent as well as preparation method and application thereof

Abstract

The invention provides an SIS pressure-sensitive hot melt adhesive green cleaning agent. The SIS pressure-sensitive hot melt adhesive green cleaning agent is composed of the following components in percentage by volume: 0-10% of ester compounds, 35-50% of natural terpene compounds, 35-50% of alkane compounds and 2-8% of 95% ethanol. The SIS pressure-sensitive hot melt adhesive cleaning agent can efficiently dissolve solid SIS pressure-sensitive hot melt adhesive, and the situation that a factory needs to input a large amount of manpower and material resources to clean residual hot melt adhesive on equipment after hot melt adhesive production is finished is avoided; the cleaning agent depends on the theoretical basis of material chemistry and polymer chemistry, and by utilizing the polarity similar dissolvability principle and the Hansen solubility parameter rule (according to the Hansen solubility parameter theory, the closer the dispersion components of the two are, the higher the mutual dissolution degree is), it is ensured that the cleaning agent efficiently dissolves the SIS pressure-sensitive hot melt adhesive; the SIS pressure-sensitive hot melt adhesive can be removed in a simple, non-destructive, low-toxicity and comfortable-smell manner; the SIS pressure-sensitive hot melt adhesive disclosed by the invention is good in cleaning effect and free from obvious peculiar smell, and can better meet the increasing requirements of domestic factories on cleaning of SIS pressure-sensitive hot melt adhesives left on production equipment.

Description

Technical Field

[0001] The invention relates to a green cleaning agent for SIS pressure-sensitive hot-melt adhesive. Background Art

[0002] Hot melt adhesive patches belong to a category of transdermal absorption preparations. Their preparation process generally involves using high temperature to mix and melt the excipient matrix, softener, tackifier, active pharmaceutical ingredient (API), etc., stirring to form a uniform paste, which is then evenly coated on the surface of a non-woven fabric through an applicator and used after cooling and solidification. SIS hot melt adhesive is a hot melt pressure-sensitive adhesive based on styrene-isoprene-styrene block copolymer. The paste needs to go through steps such as heating, melting, mixing, and coating in the production process. After each production is completed, a large amount of colloid will remain in the relevant equipment. Before the next production, the residual colloid in the equipment needs to be cleaned. Although organic solvents such as toluene or xylene can effectively remove hot melt adhesive colloid, such solvents are extremely toxic and will significantly affect the health of operators. Therefore, they cannot be used in production practice. In addition to toluene solvents, other single organic solvents used in the industry have low cleaning efficiency, high cost, and require a lot of manpower, which is extremely inconvenient. Therefore, it is urgent to develop an excellent green cleaning agent for SIS pressure-sensitive hot melt adhesive so that it can be better applied in actual production.

[0003] Typically, SIS is a styrene-isoprene-styrene ternary block copolymer, exhibiting the dual properties of rubber and plastic. Its structure consists of two incompatible phases, with PS dispersed within the continuous polyisoprene phase, providing both vulcanization and reinforcement. The polyisoprene blocks within its structure, with multiple methyl side chains, provide strong adhesion and high elasticity, but are susceptible to aging and resistance to water, alcohol, weak acids, and weak bases. However, esters, ketones, aliphatic hydrocarbons, aromatic hydrocarbons, and ether-based organic solvents such as tetrahydrofuran can dissolve or swell SIS. Because this cleaning agent is used in medical pressure-sensitive hot-melt adhesives, its ingredients must comply with green chemistry standards. The formulation needs to be mild in odor, low in toxicity to humans, and easy to clean.

[0004] At present, there are relatively few domestic studies on green cleaning agents for SIS pressure-sensitive hot melt adhesives. This will effectively fill the technical gap in the field of hot melt adhesive cleaning, and will also promote safer production in downstream application areas such as packaging and medical dressings, with significant economic benefits and social value.

[0005] Therefore, it is quite necessary to develop a green cleaning agent that can fully remove SIS pressure-sensitive hot melt adhesive. Summary of the Invention

[0006] The invention provides an SIS pressure-sensitive hot-melt adhesive green cleaning agent, a preparation method thereof, and an application thereof.

[0007] The present invention provides a SIS pressure-sensitive hot melt adhesive green cleaning agent, which is composed of the following components in percentage by volume:

[0008] Ester compounds 0% to 10%, natural terpenes 35% to 50%, alkanes 35% to 50%, 95% ethanol 2% to 8%;

[0009] The ester compound is selected from one or more of ethyl acetate, propyl acetate, n-butyl acetate, and amyl acetate; the natural terpene compound is one or two of D-limonene and menthone; and the alkane compound is selected from one or two of cyclohexane and isododecane.

[0010] Preferably, it is composed of the following components in percentage by volume:

[0011] Ester compounds 3% to 6%, natural terpene compounds 42% to 48%, alkane compounds 42% to 48%, 95% ethanol 3% to 6%.

[0012] More preferably, it is composed of the following components in percentage by volume:

[0013] Butyl acetate 6%, D-limonene 45%, cyclohexane 45%, 95% ethanol 4%; or,

[0014] Butyl acetate 3%, D-limonene 47%, cyclohexane 45%, 95% ethanol 5%; or,

[0015] Propyl acetate 5%, D-limonene 45%, cyclohexane 45%, 95% ethanol 5%; or,

[0016] Ethyl acetate:butyl acetate = 2:8 5%, D-limonene 45%, isododecane 46%, 95% ethanol 4%; or,

[0017] Propyl acetate 5%, menthone 47%, isododecane 43%, 95% ethanol 5%; or,

[0018] Amyl acetate:butyl acetate = 1:1 6%, D-limonene 44%, isododecane 46%, 95% ethanol 4%; or,

[0019] Amyl acetate 4%, D-limonene 45%, cyclohexane 47%, 95% ethanol 4%; or,

[0020] Propyl acetate:butyl acetate = 1:1 6%, D-limonene 43%, cyclohexane 47%, 95% ethanol 4%.

[0021] The present invention provides a SIS pressure-sensitive hot melt adhesive green cleaning agent, which comprises the following steps:

[0022] a. Take the components in each volume percentage;

[0023] b. Add ester compounds, natural terpene compounds, alkane compounds and 95% ethanol in sequence, and mix thoroughly with ultrasound.

[0024] The hot melt adhesive cleaning agent described in the present invention is suitable for cleaning hot melt adhesive residues based on styrene-isoprene-styrene (SIS) block copolymers. The cleaning agent formulation has excellent applicability for cleaning SIS block copolymers and can effectively remove residues from a variety of SIS pressure-sensitive hot melt adhesive systems, including but not limited to a specific composite hot melt adhesive system (the specific system composition includes: 40±2% SIS block copolymer, 14.5±0.5% polybutene, 0.5±0.1% butylated hydroxytoluene, and 45±2% high-viscosity liquid paraffin). In this specific composite system, the performance and effect of the cleaning agent are fully exerted and the advantages are significant. However, for other SIS block copolymer systems, after reasonable adjustment of the formulation parameters, the cleaning agent formulation can also show relatively good cleaning effects.

[0025] To this end, the present invention provides a green cleaning agent formula for SIS pressure-sensitive hot melt adhesive, which aims to solve equipment problems caused by SIS pressure-sensitive hot melt adhesive residue in existing industrial production, including the inability to use the reactor normally, blockage of pipelines and roller glue coating points, and damage to the equipment service life caused by traditional cleaning methods (such as scraping or high-temperature burning).

[0026] The solubility parameters of the screened alkane compounds are highly matched with the styrene segment in SIS and the liquid paraffin in the hot melt adhesive component, which conforms to the solubility parameter matching principle. According to the Hansen solubility parameter theory, the solubility parameters of styrene and the selected alkane compounds meet the principle of similar solubility parameters, indicating that the two have good mutual solubility. In addition, its efficient solubility in styrene and liquid paraffin is also based on the thermodynamic compatibility dominated by the dispersion force of the two and the kinetics of rapid diffusion of their small molecules.

[0027] The screened natural terpene compounds can cause the isoprene segments in the SIS polymer blocks to relax, allowing solvent molecules to insert into the segments and weaken the interchain van der Waals forces, resulting in disentanglement of the segments. At the same time, since the swelling rate of polyisoprene in terpene compounds is significantly higher than that of traditional solvents such as toluene, this type of component can quickly swell the SIS colloid.

[0028] The screened ester compounds serve as bridge solvents, with medium polarity and solubility parameters between alkanes and natural terpenes. They can enhance the continuity of the solvent system and promote the synergistic penetration and dissolution of mixed solvents.

[0029] Ethanol is used to adjust the polarity of the overall solvent. As a polarity regulator and swelling agent, ethanol, while having poor direct compatibility with SIS, can disrupt the small amount of polar resin in the colloid through hydrogen bonding, promoting rapid swelling of the colloid and facilitating the entry of other components into the colloid, thus improving the compatibility of the solvent with the colloid.

[0030] Through the synergistic effect of the above multiple ingredients, the efficient dissolution of SIS pressure-sensitive hot melt adhesive colloid is finally achieved. DETAILED DESCRIPTION

[0031] The following describes the implementation of the present invention using specific embodiments. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. It is apparent that the described embodiments are only a portion of the present invention, not all of it. All other embodiments derived by persons of ordinary skill in the art based on the embodiments herein without inventive effort are intended to fall within the scope of protection of the present invention.

[0032] Solubility determination:

[0033] Equipment: constant temperature water bath, analytical balance (1 / 10,000 balance), high-speed centrifuge, fume hood, vacuum drying oven, ultrasonic cleaner, 25 mL conical flask, 25 mL graduated cylinder, 500 mL reagent bottle, scissors.

[0034] Reagents: corresponding formula solvents (analytical grade), SIS pressure-sensitive hot melt adhesive blocks

[0035] Determination steps:

[0036] 1. Sample processing: First use clean scissors to cut the colloid into small pieces with a diameter of about 5 mm for later use.

[0037] 2. Weigh the sample: weigh an excessive amount of small rubber blocks and place them on weighing paper (determined in the preliminary experiment). Wait for the balance data to stabilize and then record the mass m1 of the rubber block. Transfer the rubber block to a 25mL conical flask for later use. 3. Reagent preparation: In a fume hood, according to the corresponding formula in the example, prepare the components into a mixed solvent according to the ratio, pour it into the reagent bottle and seal the bottle mouth, mix it ultrasonically for 5 minutes and set aside. 4. Measure the reagent: In a fume hood, use a 25mL measuring cylinder to measure 10mL of solvent (marked as V), and quickly transfer the solvent to a 25mL conical flask. 5. Dissolve the colloid: Gently shake the conical flask by hand to fully immerse the rubber block in the solvent, seal the mouth of the conical flask to prevent excessive volatilization of the solvent, fix the conical flask in a constant temperature water bath, set the temperature to 25°C, and dissolve it for 12 hours. 6. Separate the undissolved matter: Transfer all contents of the conical flask to a 15 mL centrifuge tube and centrifuge at 10,000 rpm for 15 minutes. Discard the solution and dry the tube in a vacuum drying oven at 45°C for 1 hour. After drying, use an analytical balance (1 / 10,000) to measure and record the residual solid mass (m²). 7. Calculate the solubility: Calculate the solvent solubility (in mg / mL) according to the following formula: [S = (m¹ - m²) / V]. 8. Repeat the above steps three times for each solvent formulation and calculate the average value.

[0038] Cleaning effect measurement

[0039] Equipment: analytical balance (1 / 10,000), constant temperature water bath, scissors, 1mL pipette

[0040] Consumables: 5mL EP tube, 1mL pipette tip

[0041] Reagents: corresponding formula solvents (analytical grade), SIS pressure-sensitive hot melt adhesive blocks

[0042] Test steps:

[0043] 1. Sample processing: First use clean scissors to cut the colloid into small pieces with a diameter of about 5 mm for later use.

[0044] 2. Use an analytical balance to weigh three 320 mg portions of colloid and transfer them into three 5 mL centrifuge tubes.

[0045] 3. Use a pipette to draw 1 mL of the corresponding example formula solvent and inject it into the centrifuge tube.

[0046] 4. Close the centrifuge tube cap and gently shake to completely immerse the colloid in the solvent. Then, place the centrifuge tube in a 25°C constant temperature water bath for 24 hours.

[0047] 5. Take out the centrifuge tube and observe and compare the cleaning effect (the cleaning effect is judged by observing whether there is any colloid residue on the wall of the centrifuge tube).

[0048] Example 1

[0049] This embodiment provides a green cleaning agent for SIS pressure-sensitive hot melt adhesive. The volume percentages of the components are shown in Table 1:

[0050]

[0051] Preparation method: Add butyl acetate, D-limonene, cyclohexane, and 95% ethanol in corresponding amounts to a clean reagent bottle, seal the bottle mouth, and mix by ultrasonication for 5 minutes to complete the preparation.

[0052] Example 2

[0053] This embodiment provides a green cleaning agent for SIS pressure-sensitive hot melt adhesive. The volume percentages of the components are shown in Table 2:

[0054]

[0055] Preparation method: Add butyl acetate, D-limonene, cyclohexane, and 95% ethanol in corresponding amounts to a clean reagent bottle, seal the bottle mouth, and mix by ultrasonication for 5 minutes to complete the preparation.

[0056] Example 3

[0057] This embodiment provides a green cleaning agent for SIS pressure-sensitive hot melt adhesive. The volume percentage of each component is shown in Table 3.

[0058]

[0059] Preparation method: Add propyl acetate, D-limonene, cyclohexane, and 95% ethanol in corresponding amounts to a clean reagent bottle, seal the bottle mouth, and ultrasonically mix for 5 minutes to complete the preparation.

[0060] Example 4

[0061] This embodiment provides a green cleaning agent for SIS pressure-sensitive hot melt adhesive. The volume percentages of the components are shown in Table 4:

[0062]

[0063] Preparation method: Add ethyl acetate, butyl acetate, D-limonene, isododecane, and 95% ethanol in corresponding amounts to a clean reagent bottle, seal the bottle mouth, and ultrasonically mix for 5 minutes to complete the preparation.

[0064] Example 5

[0065] This embodiment provides a green cleaning agent for SIS pressure-sensitive hot melt adhesive. The volume percentages of the components are shown in Table 5:

[0066]

[0067] Preparation method: Add propyl acetate, menthone, isododecane and 95% ethanol in corresponding amounts to a clean reagent bottle, seal the bottle mouth, and mix by ultrasonication for 5 minutes to complete the preparation.

[0068] Example 6

[0069] This embodiment provides a green cleaning agent for SIS pressure-sensitive hot melt adhesive. The volume percentages of the components are shown in Table 6:

[0070]

[0071] Preparation method: Add amyl acetate, butyl acetate, D-limonene, isododecane, and 95% ethanol in corresponding amounts to a clean reagent bottle, seal the bottle mouth, and ultrasonically mix for 5 minutes to complete the preparation.

[0072] Example 7

[0073] This embodiment provides a green cleaning agent for SIS pressure-sensitive hot melt adhesive. The volume percentages of the components are shown in Table 7:

[0074]

[0075] Preparation method: Add amyl acetate, D-limonene, cyclohexane, and 95% ethanol in corresponding amounts to a clean reagent bottle, seal the bottle mouth, and ultrasonically mix for 5 minutes to complete the preparation.

[0076] Example 8

[0077] This embodiment provides a green cleaning agent for SIS pressure-sensitive hot melt adhesive. The volume percentages of the components are shown in Table 8:

[0078]

[0079] Preparation method: Add propyl acetate, butyl acetate, D-limonene, cyclohexane, and 95% ethanol in corresponding amounts to a clean reagent bottle, seal the bottle mouth, and ultrasonically mix for 5 minutes to complete the preparation.

[0080] Test Example: Since there are currently no products specifically designed for SIS pressure-sensitive hot melt adhesive cleaning on the market, it is impossible to find similar products for comparison. However, since the factory currently uses ethanol soaking followed by ethyl acetate dissolution to remove residual colloid on the equipment, pure ethyl acetate was selected as the comparison sample. Detailed data is shown in Table 9:

[0081]

[0082] Example 9 Component screening test of the present invention

[0083] This example provides a single-ingredient formulation. A preliminary study is first conducted on the dissolution of hot melt adhesives using a single commonly used organic solvent. The experimental parameters associated with each formulation are shown in Table 10:

[0084]

[0085] Example 10 Screening test of the two-to-two ratio of the components of the present invention

[0086] This example provides a recipe for mixing two ingredients to further investigate the dissolution of hot melt adhesives using various commonly used organic solvents. The experimental parameters related to each recipe are shown in Table 11:

[0087]

[0088] Example 11 Control experiment of different proportions of the components of the present invention

[0089] This example provides a formulation of three or more components, and further investigates the dissolution of hot melt adhesives by various commonly used organic solvents. The experimental parameters related to each formulation are shown in Table 12:

[0090]

[0091] Comparative Example Summary:

[0092] Through screening tests on different formulations of single solvents, two-component solvents, and multi-component solvents in Examples 9-11 above, it was fully verified that in the research and development process of SIS pressure-sensitive hot melt adhesive cleaning agents, it is difficult to achieve efficient cleaning effects by relying solely on a single or a small number of solvent components. This provides strong experimental data support for the final determination of the preferred formulation of the present invention, and clarifies that only with the synergistic effect of the various components of this preferred formulation can efficient and green cleaning of SIS pressure-sensitive hot melt adhesives be achieved, thus meeting the requirements for cleaning agent performance in actual production applications.

[0093] in conclusion:

[0094] The single-solvent and dual-solvent examples of the present invention demonstrate that a single component cannot achieve efficient dissolution of SIS pressure-sensitive hot melt adhesive. At the same time, the mixed solvent formulations of Examples 3-5 can all achieve efficient dissolution of adhesive blocks. We determined the final preferred formulation through comprehensive consideration of the cleaning effects of the formulations.

[0095] The pure ethyl acetate used in the test example failed to effectively dissolve the colloid, resulting in poor cleaning results. In actual production, workers must physically remove any remaining colloid. Because the cleaning agent of the present invention is non-corrosive to equipment and facilitates secondary cleaning, the experimental test results show that the cleaning agent of the present invention significantly outperforms pure ethyl acetate in cleaning performance. This formulation effectively removes solid colloid components adhering to equipment, meets green chemistry requirements, and reduces health risks to operators.

[0096] For those skilled in the art, the present invention is not limited to the details of the above-mentioned exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention; therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is limited by the appended claims rather than the above description, and it is intended that all changes that fall within the meaning and scope of the equivalent elements of the claims are included in the present invention.

[0097] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any minor modifications, equivalent replacements, and improvements made to the above embodiments based on the technical essence of the present invention shall be included in the scope of protection of the technical solution of the present invention.

Claims

1. A green cleaning agent for SIS pressure-sensitive hot melt adhesive, characterized by: It is composed of the following components in percentage by volume: Ester compounds 0% to 10%, natural terpenes 35% to 50%, alkanes 35% to 50%, 95% ethanol 2% to 8%; The ester compound is selected from one or more of ethyl acetate, propyl acetate, n-butyl acetate, and amyl acetate; the natural terpene compound is one or two of D-limonene and menthone; and the alkane compound is selected from one or two of cyclohexane and isododecane.

2. The SIS pressure-sensitive hot melt adhesive green cleaning agent according to claim 1, characterized in that: It is composed of the following components in percentage by volume: Ester compounds 3% to 6%, natural terpene compounds 42% to 48%, alkane compounds 42% to 48%, 95% ethanol 3% to 6%.

3. The SIS pressure-sensitive hot melt adhesive green cleaning agent according to claim 2, characterized in that: It is composed of the following components in percentage by volume: Butyl acetate 6%, D-limonene 45%, cyclohexane 45%, 95% ethanol 4%; or, Butyl acetate 3%, D-limonene 47%, cyclohexane 45%, 95% ethanol 5%; or, Propyl acetate 5%, D-limonene 45%, cyclohexane 45%, 95% ethanol 5%; or, Ethyl acetate:butyl acetate = 2:8 5%, D-limonene 45%, isododecane 46%, 95% ethanol 4%; or, Propyl acetate 5%, menthone 47%, isododecane 43%, 95% ethanol 5%; or, Amyl acetate:butyl acetate = 1:1 6%, D-limonene 44%, isododecane 46%, 95% ethanol 4%; or, Amyl acetate 4%, D-limonene 45%, cyclohexane 47%, 95% ethanol 4%; or, Propyl acetate:butyl acetate = 1:1 6%, D-limonene 43%, cyclohexane 47%, 95% ethanol 4%.

4. A green cleaning agent for SIS pressure-sensitive hot melt adhesive according to any one of claims 1 to 3, characterized in that: It includes the following steps: a. Take the components of each volume percentage; b. Add ester compounds, natural terpene compounds, alkane compounds and 95% ethanol in sequence, and mix thoroughly with ultrasound.

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