Preparation process of hot-melt pressure-sensitive adhesive with low volatility

Abstract

The invention relates to the technical field of hot-melt pressure-sensitive adhesives, and particularly discloses a preparation process of a hot-melt pressure-sensitive adhesive with low volatility, the hot-melt pressure-sensitive adhesive comprises the following raw materials by mass: 20-30 parts of SBS, 40-80 parts of thickening resin, 30-60 parts of a softener, 0.5-2 parts of an antioxidant, and 15-20 parts of a plasticizer. The plasticizer comprises any one of dioctyl phthalate and dioctyl terephthalate, the amount of the plasticizer is 10-30 parts, so that the rubber material is soft and has good wear resistance and aging resistance, the adding amount of DOP is about 10-15 parts, and the adding amount of the adhesive is 15-25 parts, so that the adhesive has good flexibility and adhesive force; under the protection of argon, the SBS, the thickening resin, the softening agent, the antioxidant, the plasticizer and the adhesive are fully mixed to prepare the hot-melt pressure-sensitive adhesive. The plasticizer is added according to a certain proportion and is fully mixed and matched with the raw materials of the hot-melt pressure-sensitive adhesive, so that the volatility resistance of the prepared hot-melt pressure-sensitive adhesive is improved.

Description

Technical Field

[0001] The invention relates to the technical field of hot-melt pressure-sensitive adhesives, and in particular to a preparation process of a hot-melt pressure-sensitive adhesive with low volatility. Background Art

[0002] Hot melt pressure sensitive adhesive is a type of adhesive that can be applied in a heated and molten state, can quickly produce a bonding effect when cooled to a solid state, and can be firmly bonded to the adherend with just slight finger pressure. It has the characteristics of both hot melt adhesive and pressure sensitive adhesive. Hot melt adhesive is applied by heating and melting, and forms a bond after cooling and solidifying; pressure sensitive adhesive can achieve bonding under slight pressure without the help of solvents or water. Hot melt pressure sensitive adhesive combines the advantages of both. It is solid at room temperature and has the viscosity of pressure sensitive adhesive. When heated, it is easy to apply like hot melt adhesive and is convenient to use.

[0003] The viscosity of hot-melt pressure-sensitive adhesive depends on the synergistic effect between its components. Rapid volatilization may lead to the loss of key components such as tackifying resin, destroying the balance of the viscosity system, or the adhesive layer is prone to deformation and fracture when subjected to external forces such as stretching and shearing, and cannot effectively transfer stress, resulting in bonding failure. After the tackifying resin evaporates, the adhesive's wetting and adsorption ability on the surface of the adherend decreases, which directly causes the initial viscosity to deteriorate and the object to easily fall off after being pasted. Summary of the invention

[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] The present invention provides a preparation process of a hot-melt pressure-sensitive adhesive with low volatility, which can solve the problem of excessively fast volatilization rate. The specific scheme is as follows: A process for preparing a hot melt pressure sensitive adhesive with low volatility, comprising raw materials of the following mass components: SBS 20-30 parts, thickening resin 40-80 parts, softener 30-60 parts, antioxidant 0.5-2 parts, plasticizer 15-20 parts, the plasticizer includes any one of dioctyl phthalate and dioctyl terephthalate, the plasticizer is 10-30 parts, so that the rubber material is soft and has good wear resistance and anti-aging properties, DOP is added in an amount of about 10-15 parts, and adhesive is 15-25 parts, so that the adhesive has good flexibility and adhesion; Under the protection of argon gas, SBS, thickening resin, softener, antioxidant, plasticizer and adhesive are fully mixed to prepare a hot melt pressure sensitive adhesive.

[0006] As a preferred technical solution of the present invention, prepare 20-30 parts of SBS, 40-80 parts of thickening resin, 30-60 parts of softening agent, 0.5-2 parts of antioxidant, 15-20 parts of plasticizer. The plasticizer includes any one of dioctyl phthalate and dioctyl terephthalate, the plasticizer is 10-30 parts and the styrene content is about 25%; naphthenic oil is used as the softening agent; antioxidant 1010. Put the above raw materials into a preheated reaction kettle, and the reaction kettle needs to be equipped with a stirrer to ensure uniform mixing of the materials.

[0007] As a preferred technical solution of the present invention, after putting them into the reaction kettle, prepare a thermometer, measuring instruments and cooling equipment. The thermometer is used to monitor the temperature of the mixed materials inside the reaction kettle in real time. The cooling equipment includes any one of air-cooling equipment or water-cooling equipment. Avoid agglomeration when putting in the raw materials.

[0008] As a preferred technical solution of the present invention, start stirring and slowly add the measured softening agent. Slowly adding the softening agent allows SBS to fully contact and swell. The stirring speed is controlled at 50-100 revolutions per minute, so that SBS gradually swells in the softening agent. This process takes 1-2 hours and the temperature is maintained at 60-80 °C.

[0009] As a preferred technical solution of the present invention, after the swelling is completed, gradually raise the temperature to 150-180 °C, increase the stirring speed to 100-150 revolutions per minute, and maintain this temperature and stirring speed for 1-2 hours to completely dissolve SBS and form a uniform viscous liquid. After SBS is completely dissolved, lower the temperature to 130-150 °C, add the measured thickening resin in batches and maintain the stirring speed at 00-150 revolutions per minute, and stir for 1-2 hours to fully mix the thickening resin and SBS evenly.

[0010] As a preferred technical solution of the present invention, add the antioxidant and continue stirring for 30-60 minutes, maintain the temperature at 130-150 °C, and let the antioxidant be evenly dispersed in the system to play an antioxidant role. Finally, add the plasticizer and stir evenly for 20-30 minutes, and keep the temperature unchanged.

[0011] As a preferred technical solution of the present invention, start the cooling equipment after preparing the hot melt pressure-sensitive adhesive. When starting the air-cooling equipment, turn on the cooling fan and adjust the angle of air-cooling so that it is aimed at the hot melt pressure-sensitive adhesive for air-cooling for 5-10 minutes to cool and solidify the hot melt pressure-sensitive adhesive; when starting the water-cooling equipment, the water-cooling equipment has a container for loading the hot melt pressure-sensitive adhesive and the container is in cold water, and it is left standing in the cold water for 20-35 minutes, and the cold water is circulated.

[0012] Compared with the prior art, the present invention can at least achieve one of the following beneficial effects: By increasing a plasticizer in a certain proportion and fully mixing and proportioning it with the raw materials of the hot-melt pressure-sensitive adhesive, the anti-volatility performance of the hot-melt pressure-sensitive adhesive after being made is increased. After the anti-volatility performance is improved, the active ingredients in the hot-melt pressure-sensitive adhesive can exist more stably in the colloid system, and the loss of viscous substances due to volatilization will not occur, so that the viscosity of the adhesive can be maintained stably for a long time, and the initial viscosity and holding viscosity can be better maintained, ensuring the durability of the bonding effect; Increasing the cohesive strength helps to maintain the chemical structure and physical cross-linking state inside the hot-melt pressure-sensitive adhesive, making the cohesive strength of the colloid more stable. This means that when subjected to external forces, the adhesive layer can better maintain its integrity and is not prone to damage phenomena such as cracking and breaking, improving the reliability and stability of bonding.

[0013] Other features and advantages of the present invention will be described in the subsequent specification, and some of them will become obvious from the specification or be understood by implementing the present invention. Detailed implementation manners Examples

[0014] The present invention provides a preparation process for a hot-melt pressure-sensitive adhesive with low volatility performance, including raw materials with the following mass components: 20 - 30 parts of SBS, 40 - 80 parts of thickening resin, 30 - 60 parts of softening agent, 0.5 - 2 parts of antioxidant, 15 - 20 parts of plasticizer. The plasticizer includes any one of dioctyl phthalate and dioctyl terephthalate. The plasticizer is 10 - 30 parts, making the rubber compound soft and having good wear resistance and anti-aging performance. The addition amount of DOP is about 10 - 15 parts, and 15 - 25 parts of adhesive, making the adhesive have good flexibility and adhesion; Under argon protection, SBS, thickening resin, softening agent, antioxidant, plasticizer and adhesive are fully mixed to obtain the hot-melt pressure-sensitive adhesive.

[0015] Prepare 20 - 30 parts of SBS, 40 - 80 parts of thickening resin, 30 - 60 parts of softening agent, 0.5 - 2 parts of antioxidant, 15 - 20 parts of plasticizer. The plasticizer includes any one of dioctyl phthalate and dioctyl terephthalate. The plasticizer is 10 - 30 parts and the styrene content is about 25%; naphthenic oil is used as the softening agent; antioxidant 1010. Put the above raw materials into a preheated reaction kettle, and the reaction kettle needs to be equipped with a stirrer to ensure uniform mixing of the materials.

[0016] It should be noted that dioctyl phthalate is widely used in polyvinyl chloride plastic products, such as artificial leather, wire and cable sheaths, etc. It can effectively increase the flexibility and plasticity of plastics, and has low volatility, which helps to ensure the performance stability of plastic products during long-term use; Dioctyl terephthalate is a main plasticizer with excellent properties. It has good compatibility with PVC resin, high plasticization efficiency, lower volatility than DOP, better resistance to migration, extraction and electrical insulation properties. It is often used in PVC products with higher durability requirements, such as automotive interior materials, outdoor plastic products, etc.

[0017] After putting it into the reaction kettle, prepare a thermometer, measuring instruments and cooling equipment. The thermometer is used to monitor the temperature of the mixed materials inside the reaction kettle in real time. The cooling equipment includes any one of air-cooling equipment or water-cooling equipment. When putting in the raw materials, avoid agglomeration.

[0018] Start stirring and slowly add the measured softener. Slowly adding the softener allows SBS to fully contact and swell. The stirring speed is controlled at 50 - 100 revolutions per minute, so that SBS gradually swells in the softener. This process takes 1 - 2 hours, and the temperature is maintained at 60 - 80 °C.

[0019] After the swelling is completed, gradually raise the temperature to 150 - 180 °C, increase the stirring speed to 100 - 150 revolutions per minute, and maintain this temperature and stirring speed for 1 - 2 hours to completely dissolve SBS and form a uniform viscous liquid. After SBS is completely dissolved, lower the temperature to 130 - 150 °C, add the measured tackifying resin in batches and maintain the stirring speed at 100 - 150 revolutions per minute, and stir for 1 - 2 hours to fully mix the tackifying resin and SBS evenly.

[0020] Add antioxidant and continue stirring for 30 - 60 minutes, with the temperature maintained at 130 - 150 °C, so that the antioxidant is evenly dispersed in the system to play an antioxidant role. Finally, add plasticizer and stir evenly for 20 - 30 minutes, with the temperature remaining unchanged.

[0021] Example 2: Different from Example 1, a preparation process of a hot melt pressure - sensitive adhesive with low volatility performance includes raw materials with the following mass components: 10 - 20 parts of SBS, 30 - 50 parts of thickening resin, 20 - 25 parts of softener, 0.5 - 1 part of antioxidant, 10 - 15 parts of plasticizer. The plasticizer includes any one of dioctyl phthalate and dioctyl terephthalate. The plasticizer is 8 - 16 parts, making the rubber compound soft and having good wear resistance and anti - aging properties. The addition amount of DOP is about 5 - 8 parts, and 10 - 15 parts of adhesive, making the adhesive have good flexibility and adhesion. It should be noted that reducing the proportion of the entire raw materials, the raw materials of the hot melt pressure - sensitive adhesive, such as special polymers, high - performance tackifying resins, etc., often have higher prices. Reducing the proportion of these raw materials can directly reduce the procurement cost. For example, if the price of a certain high - quality tackifying resin in the market rises significantly, appropriately reducing its dosage, finding a suitable substitute or adjusting the proportion of other raw materials to maintain performance can effectively control the cost.

[0022] Some raw material processing requires specific temperature and pressure conditions, consuming a large amount of energy. Reducing the proportion of such raw materials can simplify the preparation process and reduce energy consumption. For example, for some polymers with high processing temperature requirements, after reducing the usage amount, the energy required for heating the reaction kettle decreases; At the same time, adjust the balance of viscosity and cohesion strength: reducing the proportion of tackifying resin can appropriately reduce the initial tack, but can improve the cohesion strength. For application scenarios that need to withstand external forces for a long time and have high requirements for holding power, such as heavy-duty packaging tapes, optimizing this balance can make the tape stick firmly without falling off for a long time.

[0023] Improve the temperature resistance performance: In some cases, reducing the amount of low-melting-point softener can improve the high-temperature resistance performance of hot-melt pressure-sensitive adhesives. For hot-melt pressure-sensitive adhesives used in high-temperature environments, such as bonding components in the automotive engine compartment, reducing the proportion of softener can avoid the flow and failure of the adhesive at high temperatures.

[0024] Dioctyl terephthalate is a main plasticizer with excellent performance, having good compatibility with PVC resin, high plasticization efficiency, lower volatility than DOP, and better migration resistance, extraction resistance and electrical insulation performance. It is often used in PVC products with high durability requirements, such as automotive interior materials, outdoor plastic products, etc.

[0025] After putting it into the reaction kettle, prepare a thermometer, measuring instruments and cooling equipment. The thermometer is used to monitor the temperature of the mixed materials inside the reaction kettle in real time. The cooling equipment includes any one of air-cooling equipment or water-cooling equipment. Avoid agglomeration when adding raw materials.

[0026] Start stirring and slowly add the measured softener. Slowly adding the softener can allow SBS to fully contact and swell. The stirring speed is controlled at 50 - 100 revolutions per minute, so that SBS gradually swells in the softener. This process takes 1 - 2 hours, and the temperature is maintained at 60 - 80 °C.

[0027] After the swelling is completed, gradually raise the temperature to 150 - 180 °C, increase the stirring speed to 100 - 150 revolutions per minute, and maintain this temperature and stirring speed for 1 - 2 hours to completely dissolve SBS to form a uniform viscous liquid. After SBS is completely dissolved, lower the temperature to 130 - 150 °C, add the measured tackifying resin in batches and maintain the stirring speed at 100 - 150 revolutions per minute, and stir for 1 - 2 hours to fully mix the tackifying resin and SBS evenly.

[0028] Add antioxidant and continue stirring for 30 - 60 minutes, with the temperature maintained at 130 - 150 °C. Let the antioxidant be evenly dispersed in the system to play an antioxidant role. Finally, add plasticizer and stir evenly for 20 - 30 minutes, with the temperature remaining unchanged.

[0029] It should be noted that reducing reaction complexity: Some raw materials are involved in complex reactions and require stringent control conditions. Reducing their usage can simplify the reaction process and reduce the difficulty and risk of process control. For example, for some raw materials that require precise control of reaction temperature, time, and acidity / alkalinity, reducing their use can lower the operation difficulty.

[0030] Improving production efficiency: Simplifying the process can shorten the production cycle and improve equipment utilization rate. For example, without complex reaction conditions and long reaction times, the equipment can move on to the next batch of production more quickly, enhancing the overall production efficiency.

[0031] Reducing the volatilization of harmful substances: Some raw materials may contain volatile organic compounds or harmful substances. Reducing their proportion can minimize the volatilization of harmful substances during production and use, alleviating the harm to the environment and human health. For example, reducing the use of benzene-containing plasticizers can lower benzene pollution in the workshop and the usage environment.

[0032] Furthermore, the hot melt pressure-sensitive adhesive is composed of multiple components such as a polymer matrix, tackifying resin, softener, antioxidant, etc. Adequate stirring can evenly distribute these raw materials at the microscopic level, ensuring that every part of the hot melt pressure-sensitive adhesive has the same chemical composition and ratio. For example, when the tackifying resin is evenly dispersed, the adhesive can have consistent initial tackiness in all parts; when the antioxidant is evenly distributed, it can ensure the same antioxidant performance throughout the adhesive system, thereby improving the stability and consistency of product quality and avoiding performance differences caused by local unevenness of components.

[0033] During the stirring process, different components interpenetrate and fuse with each other to form a stable and uniform microscopic structure. The uniform combination of the polymer matrix and the tackifying resin helps to construct a reasonable viscous network structure, enhancing the cohesive strength and overall performance of the colloid; for some raw materials that need to be dissolved, such as the dissolution of the polymer matrix in the softener, sufficient stirring can increase the contact area between the solute and the solvent, accelerating the dissolution rate. For example, in the case of SBS polymer in softeners such as naphthenic oil, stirring makes the SBS particles continuously contact the naphthenic oil, quickly swelling and dissolving, shortening the preparation time and improving production efficiency.

[0034] Improving flame retardancy: Some special application scenarios have requirements for the flame retardancy of hot melt pressure-sensitive adhesives. Appropriately reducing the proportion of flammable raw materials and adding flame retardants in combination can improve the flame retardancy of the product. For example, for adhesives used for internal bonding in electronic devices, reducing the amount of flammable raw materials can reduce the fire hazard.

[0035] Stirring can break the locally high-viscosity or low-viscosity regions that may appear inside the colloid, making the viscosity of the entire adhesive liquid more uniform. This is beneficial for subsequent coating processes, ensuring that during the coating process, the adhesive liquid can evenly cover the substrate, avoiding problems such as uneven thickness and flow marks, and guaranteeing the coating quality.

[0036] After the hot melt pressure - sensitive adhesive is prepared, start the cooling equipment. When starting the air - cooling equipment, turn on the cooling fan and adjust the angle of air - cooling so that it is aligned with the hot melt pressure - sensitive adhesive for air - cooling for 5 - 10 minutes to allow the hot melt pressure - sensitive adhesive to cool and solidify. When starting the water - cooling equipment, the water - cooling equipment has a container for loading the hot melt pressure - sensitive adhesive and the container is in cold water. It is left standing in the cold water for 20 - 35 minutes, and the cold water is in a circulating flow pattern.

[0037] Furthermore, after the entire hot melt pressure - sensitive adhesive is made, quality inspection is required. Take a small amount of the prepared hot melt pressure - sensitive adhesive and test its appearance (should be uniform, free of impurities, and without obvious particles), viscosity (using a rotational viscometer, different application scenarios have different requirements, for example, the viscosity of the adhesive for labels is low, and the viscosity of the adhesive for packaging is high), initial tack (tested by the rolling - ball method, the value reflects the initial sticking ability), holding power (measured by a holding - power tester, showing the long - term sticking performance), and other performance indicators.

[0038] After passing the inspection, put the hot melt pressure - sensitive adhesive into a clean and dry packaging container through the bottom discharge port of the reaction kettle. Keep the material temperature during the packaging process to prevent cooling and solidification. After packaging, affix a label indicating the product name, model, production date, etc.

[0039] It should be noted that the hot melt pressure - sensitive adhesive is in a liquid state under high - temperature preparation conditions. Cooling causes it to change from a liquid state to a solid state, the distance between molecules decreases, and the intermolecular force increases, thus solidifying and forming. During this process, the viscosity of the adhesive gradually stabilizes, forming a stable bonding structure, providing reliable viscosity for subsequent use. The cooled hot melt pressure - sensitive adhesive is in a relatively stable solid state, the internal chemical reaction rate slows down, and the physical properties are also more stable, thus extending the storage period. Under reasonable storage conditions, it can maintain good performance for a long time, reduce product scrapping caused by performance changes during storage, and reduce the inventory cost and economic losses of the enterprise. The hot melt pressure - sensitive adhesive in a high - temperature liquid state has high viscosity and is easily adhered to the surface of production equipment, such as coating rollers, conveying pipelines, etc., affecting the normal operation of the equipment and increasing the difficulty of equipment cleaning and maintenance. Cooling reduces its viscosity, effectively avoiding this adhesion phenomenon, ensuring the continuous and stable operation of production equipment, and extending the service life of the equipment.

[0040] In the description of this specification, the description with reference to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above - mentioned terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0041] The devices or elements referred to in the embodiments of the present application or implied must have a specific orientation, be constructed and operate in a specific orientation, and thus cannot be construed as a limitation on the embodiments of the present application. In the description of the embodiments of the present application, the meaning of "a plurality" is two or more, unless otherwise specifically and precisely defined.

[0042] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and utilize the present invention well. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A process for preparing a hot melt pressure sensitive adhesive with low volatility, characterized in that: Raw materials including the following quality components: SBS 20-30 parts, thickening resin 40-80 parts, softener 30-60 parts, antioxidant 0.5-2 parts, plasticizer 15-20 parts, the plasticizer includes any one of dioctyl phthalate and dioctyl terephthalate, the plasticizer is 10-30 parts, so that the rubber material is soft and has good wear resistance and anti-aging properties, DOP is added in an amount of about 10-15 parts, and adhesive is 15-25 parts, so that the adhesive has good flexibility and adhesion; Under the protection of argon gas, SBS, thickening resin, softener, antioxidant, plasticizer and adhesive are fully mixed to prepare a hot melt pressure sensitive adhesive.

2. The process for preparing a hot melt pressure sensitive adhesive with low volatility according to claim 1, characterized in that: Prepare SBS, 20-30 parts, thickening resin 40-80 parts, softener 30-60 parts, antioxidant 0.5-2 parts, plasticizer 15-20 parts, the plasticizer includes any one of dioctyl phthalate and dioctyl terephthalate, the plasticizer is 10-30 parts and the styrene content is about 25%; cyclohexane oil is used as a softener; antioxidant 1010, put the above raw materials into a preheated reactor, the reactor needs to have its own agitator to ensure uniform mixing of the materials.

3. The process for preparing a hot melt pressure sensitive adhesive with low volatility as claimed in claim 2, characterized in that: After the mixture is placed in the reactor, a thermometer, a measuring instrument and a cooling device are prepared. The thermometer is used to monitor the temperature of the mixture in the reactor in real time. The cooling device includes either an air cooling device or a water cooling device to avoid agglomeration when the raw materials are put in.

4. The process for preparing a hot melt pressure sensitive adhesive with low volatility as claimed in claim 3, characterized in that: Start stirring and slowly add the measured softener. Slowly adding the softener allows the SBS to fully contact and swell. The stirring speed is controlled at 50-100 rpm to gradually swell the SBS in the softener. This process takes 1-2 hours and the temperature is maintained at 60-80°C.

5. The process for preparing a hot melt pressure sensitive adhesive with low volatility as claimed in claim 4, characterized in that: After the swelling is completed, the temperature is gradually increased to 150-180° C., the stirring speed is increased to 100-150 rpm, and the temperature and stirring speed are maintained for 1-2 hours to completely dissolve the SBS and form a uniform viscous liquid. After the SBS is completely dissolved, the temperature is lowered to 130-150° C., and the measured tackifying resin is added in batches while maintaining the stirring speed of 00-150 rpm and stirring for 1-2 hours to fully mix the tackifying resin and the SBS.

6. A process for preparing a hot melt pressure sensitive adhesive with low volatility as claimed in claim 5, characterized in that: Add antioxidant and continue stirring for 30-60 minutes, maintaining the temperature at 130-150°C, so that the antioxidant is evenly dispersed in the system to play an antioxidant role. Finally, add plasticizer and stir evenly for 20-30 minutes, keeping the temperature unchanged.

7. A process for preparing a hot melt pressure sensitive adhesive with low volatility as claimed in claim 6, characterized in that: After the hot melt pressure sensitive adhesive is prepared, the cooling device is started. When the air cooling device is started, the heat dissipation fan is turned on and the air cooling angle is adjusted so that the fan is aimed at the hot melt pressure sensitive adhesive for air cooling for 5-10 minutes, so that the hot melt pressure sensitive adhesive is cooled and solidified; When the water cooling device is started, the water cooling device is provided with a container loaded with hot melt pressure sensitive adhesive and the container is placed in cold water and is left to stand in the cold water for 20-35 minutes, and the cold water is in a circulating flow type.