WO2023177038A1 - Method for preparing adhesive by using low-carbon emission, and method for manufacturing adhesive tape manufactured using same - Google Patents

Abstract

The present invention relates to a method for preparing an adhesive by using a low-carbon emission, wherein the adhesive comprises an adhesive resin, a polymerization initiator, a low-boiling-point solvent and a curing agent, and the adhesive resin is prepared through: a first step of mixing a hydrophilic monomer and a solvent, thereby preparing a colloidal polymer; and a second step of mixing the colloidal polymer and a hydrophobic monomer, thereby preparing a sticky polymer.

Description

A method of manufacturing an adhesive using a low-carbon emission process and a method of manufacturing an adhesive tape manufactured using the same.

The present invention relates to a method for manufacturing an adhesive using a low-carbon emission process and a method for manufacturing an adhesive tape manufactured using the same. More specifically, to manufacture an adhesive with excellent adhesion while applying an improved manufacturing process that can reduce carbon emissions. It relates to a manufacturing method that can be made and a method of manufacturing an adhesive tape using the adhesive.

Recently, there has been a demand for the application of low-carbon emission processes throughout the industry, and improved processes that can reduce carbon emissions in the production of various chemical products are being developed. Among these chemical products, adhesives are used to manufacture adhesive sheets or adhesive films that can be attached and detached to adherends, and are generally manufactured by mixing ingredients including monomers, solvents, polymerization initiators, curing agents, and additives. At this time, sufficient equipment operation time and energy consumption for heating are required to meet the required physical properties of the adhesive, and this production activity itself is a cause of carbon emissions.

Therefore, in the adhesive manufacturing process, there is a need to develop an improved process that can reduce carbon emissions throughout the process while ensuring sufficient performance of the adhesive.

The present invention was developed in consideration of the above-described prior art, and its purpose is to provide a method for manufacturing an adhesive using an improved process that significantly reduces carbon emissions compared to existing processes.

The method of manufacturing an adhesive using the low-carbon emission process of the present invention to solve the above problems is a method of producing an adhesive containing an adhesive resin, a polymerization initiator, a low boiling point solvent, and a curing agent, wherein the adhesive resin is a mixture of a hydrophilic monomer and a solvent. It is characterized in that it is manufactured by including a first step of producing a colloidal polymer and a second step of producing a sticky polymer by mixing a hydrophobic monomer with the colloidal polymer.

At this time, the low boiling point solvent preferably has a boiling point of 80°C or lower.

In addition, the adhesive preferably has a non-volatile matter (NVM) content of 50% by weight or more and a viscosity of 20 to 200 kcps.

Additionally, an adhesive tape can be manufactured including a process of coating a substrate with the adhesive produced using the adhesive manufacturing method of the present invention.

The method for manufacturing an adhesive according to the present invention shows the effect of applying a low-carbon emission process by applying an improved process that significantly reduces carbon emissions compared to existing processes.

In addition, a high concentration of adhesive can be produced through a low-carbon emission process, which has the effect of increasing production efficiency.

1 is a conceptual diagram showing a process for manufacturing the adhesive resin of the present invention.

Figure 2 shows the results of observing the change in turbidity over the course of the reaction.

Figure 3 shows the results of measuring the viscosity change at each reaction step in Synthesis Examples 1 to 6.

Hereinafter, the present invention will be described in more detail. Terms or words used in this specification and claims should not be construed as limited to their common or dictionary meanings, and the inventor may appropriately define the concept of terms in order to explain his or her invention in the best way. It must be interpreted with meaning and concept consistent with the technical idea of the present invention based on the principle that it is.

The present invention relates to a method of manufacturing an adhesive using a low-carbon emission process. In the manufacture of adhesives, a low-carbon emission process must meet the following conditions from both a technical and economic perspective.

First, the productivity of the production utility must be increased by increasing the concentration of the adhesive. In other words, it must be possible to increase efficiency relative to operating time. To achieve this, the volatilization time of the solvent used in the production of the adhesive must be reduced and the amount of volatile solvent must be reduced. For this purpose, a low boiling point solvent must be used and a suitable process must be developed. Additionally, energy consumption must be reduced by lowering the overall construction temperature of production utilities. Despite these improvements in process conditions, the physical properties of the adhesive should not deteriorate.

The present invention relates to a method of manufacturing an adhesive by applying an improved process to meet the conditions of such a low-carbon emission process. For this purpose, in the manufacturing process of an adhesive containing an adhesive resin, a polymerization initiator, a low boiling point solvent, and a curing agent, the first step of producing a colloidal polymer by mixing a hydrophilic monomer and a solvent in the process of producing the adhesive resin; The technical feature is to apply a process that includes a second step of producing a functional polymer that develops adhesiveness by mixing a hydrophobic monomer with a colloidal polymer.

The manufacturing method of this adhesive resin can be explained with the same concept as shown in FIG. 1. First, hydrophilic monomers are dispersed in a solvent as a colloid-forming material (Figure 1a). When relatively hydrophobic monomers are mixed here, as shown in Figure 1b, a colloid-forming material and hydrophobic monomers for developing adhesiveness are mixed together. In this state, as shown in Figure 1c, micelles are formed by hydrophilic monomers, and as the molecular weight of the hydrophobic monomer increases, the hydrophobic monomer permeates into the micelle due to the difference in solubility. As this second stage reaction progresses, polymerization (oligomerization) of the monomers present inside the micelle progresses to form an adhesive-generating functional polymer (Figure 1d), making it possible to obtain the adhesive resin desired in the present invention. do. The polymer mentioned in the manufacturing process of the present invention should be understood as an oligomer-like form in which the monomer has a high molecular weight rather than a typical polymer resin.

In general, there is a problem that the solubility decreases as the polymer is converted from a monomer to an oligomer. However, by going through a two-step reaction as in the present invention, dispersibility is improved due to the repulsion between micelles, so solubility can be maintained even in the polymerized state. There will be.

This reaction can be confirmed through the results in Figure 2, which observes the change in turbidity according to reaction time. In a reaction based on a solid content of 60%, turbidity is low in the first stage reaction, but it can be observed that the turbidity changes rapidly in the second stage reaction. These results are consistent with the concept of the manufacturing process of the present invention, in which a colloidal solution is formed due to micelle formation in the first stage reaction, and turbidity increases as the molecular weight increases in the second stage reaction.

In the general adhesive manufacturing process, the adhesive is manufactured by mixing monomers, polymerization initiators, solvents, curing agents, and other additives that make up the adhesive. During the mixing process, an adhesive resin is formed by polymerization of monomers.

However, in order to increase production efficiency, it is advantageous to increase the concentration when manufacturing the adhesive. This is because the higher the concentration of the adhesive manufactured in one batch, the higher the production volume per batch of the adhesive sheet or adhesive film coated with the adhesive. However, as the concentration of the adhesive increases, problems occur in the mixing process, so the amount of solvent has to be increased.

Increasing the amount of solvent makes it possible to manufacture a high concentration of adhesive per batch, but in order to volatilize the solvent, the equipment operation time must be increased and the temperature may have to be raised, which increases the amount of carbon emitted in the process. In addition, if the concentration is too high, the viscosity rises rapidly, which makes it impossible to apply it to the mass production process.

To solve this problem, there is a method of lowering the molecular weight of the adhesive resin, but when the molecular weight is lowered, curing is difficult due to the problem of lower solubility that occurs in polymerization as described above.

Therefore, when applying a low-carbon emission process, it is necessary to apply a reaction that can produce a high concentration of adhesive while increasing the molecular weight of the adhesive resin.

By applying the manufacturing process of the present invention, a high-concentration adhesive can be manufactured with a non-volatile matter (NVM) content of 50% by weight or more, and the viscosity is 20 to 200 kcps, which has the advantage in the process of maintaining a low viscosity. do.

In order to improve this manufacturing process, the present invention uses a low boiling point solvent and goes through a separate process of manufacturing the adhesive resin to maintain the viscosity appropriately.

That is, the process for producing the adhesive resin includes a first step of reacting a hydrophilic monomer and a solvent to produce a colloid, and a second step of adding a hydrophobic monomer to the colloid to form a protective layer.

In the first step, a colloid is prepared by reacting hydrophilic monomers dispersed in a solvent. Through this, a dispersion medium for granulated polymers is obtained. In the first step of preparing the colloid, it is advantageous to increase the crosslinking rate of the hydrophilic monomer, so itaconic acid, hydroxypropyl acrylate, and hydroxybutyl acrylate are used as the hydrophilic monomer. It is preferable to use any one of the following monomers: hydroxyethyl acrylate, 1,6-hexanediol diacrylate, and trimethylolpropane triacylate. . Additionally, maleic anhydride may be added to increase the crosslinking rate and prevent blocking. Therefore, in the first step, the dispersion medium of the monomer is crosslinked and polymerized to form a colloidal phase.

When a hydrophobic monomer is added to the colloid dispersed in a solvent, a protective layer is formed on the surface of the colloid. Through this, a non-aqueous dispersion (NAD) polymer phase is formed. By forming this NAD polymer phase, the volatilization rate of the solvent can be increased, the physical properties of the adhesive can be easily controlled, and a high concentration polymer that is environmentally resistant and eco-friendly can be synthesized, thereby increasing the efficiency of the adhesive manufacturing process.

As hydrophobic monomers for forming the adhesive development functional polymer, monomers such as butylacrylate (BA), butylmelamine, 2-ethylhexyl acrylate (2-EHA), divinyl acrylate, and trivinyl acrylate can be used. there is.

An adhesive can be manufactured by mixing a polymerization initiator, a low boiling point solvent, and a curing agent with the adhesive resin obtained through the above manufacturing process. Additionally, in the process of manufacturing the adhesive, unreacted products can be reduced by additionally adding a catalyst as needed. The adhesive manufacturing process is completed by terminating the reaction by adding a solvent, a diluent, when an adhesive of the target molecular weight is produced. Unlike the existing process in which raw materials are added all at once, when the reaction is carried out through sequential addition, the reaction time is longer, but it is easier to control the physical properties by controlling the molecular weight, and the stability of the product is also improved because the reaction proceeds sequentially. It represents an increasing advantage.

In the conventional adhesive manufacturing process, the content of non-volatile matter (NVM) was only 20 to 35% by weight based on the 8 ton adhesive manufacturing process, so the adhesive could not be manufactured at high concentration. However, in the present invention, the adhesive could not be manufactured at high concentration. In the following manufacturing process, it was found that the process could be designed so that the NVM content was more than 50% by weight.

In one embodiment, when the manufacturing process was performed in a 10t reactor with 65 to 80% by weight of volatile solvent and 20 to 35% by weight of NVM in a conventional adhesive manufacturing process, the production speed was only 10 to 18 m/min, but the production speed of the present invention was only 10 to 18 m/min. When the process was applied, it was confirmed that when the manufacturing process was performed in a 10t reactor with 40 to 50% by weight of volatile solvent and 50 to 60% by weight of NVM, the production speed was 25 to 35 m/min, dramatically increasing production efficiency.

In addition, the adhesive manufacturing method of the present invention uses a low boiling point solvent. Examples of such low boiling point solvents include acetone (boiling point 56°C), methanol (boiling point 65°C), and ethanol (boiling point 78). The solvents are mixed in an appropriate ratio. It is preferable to use it by mixing.

In order to confirm the effect of using a low boiling point solvent, a test operation was conducted based on the production of 8 tons of adhesive in a 10 ton reactor, and the temperature of the 5-stage drying furnace was adjusted as shown in Table 1. The existing process used a mixed solvent in which toluene and ethyl acetate were mixed in a volume ratio of 1:1, and the process of the present invention used a mixed solvent in which acetone and methanol were mixed in a volume ratio of 1:1.

drying furnace temperature	existing process	Process of the present invention
1st stage (℃)	100	60
2nd stage (℃)	120	80
3rd stage (℃)	140	100
4th stage (℃)	110	80
5 steps (℃)	90	60

The test operation results showed that applying the process of the present invention can lower the overall drying temperature of the drying furnace by 30 to 40°C compared to the existing process. These results serve as a factor in reducing carbon emissions by reducing the process temperature.

In addition, the results of measuring the viscosity of the adhesive according to the concentration of NVM are shown in Table 2.

NVM concentration (% by weight)	Viscosity of existing process (kcps)	Viscosity (kcps) of the process of the present invention
25	>1,000	-
30	700~1,000	-
35	400~600	-
40	300	-
50	-	100~200
55	-	50~100
60	-	25~10

Looking at the results in Table 2, it can be seen that in the process of the present invention, the content of NVM contained in the adhesive is higher than in the existing process, and despite this, the viscosity is maintained low.

From these results, the adhesive manufacturing method of the present invention can increase production efficiency by reducing utility operation time compared to existing processes, increase production speed by reducing the content of volatile solvents and using low boiling point solvents, and increase the content of NVM. It can be seen that it is a highly efficient process that can reduce carbon emissions because the viscosity range can be adjusted to increase production efficiency without reducing production efficiency.

In addition, an adhesive tape can be manufactured including the process of applying the adhesive produced using the above adhesive manufacturing method to a substrate and curing it to form an adhesive layer. The substrate is a substrate for manufacturing a tape and may be made of a material selected from polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polyurethane (PU), polycarbonate (PC), or polyimide (PI). In particular, PET is a rigid material that can act as a buffer through shock absorption, making it more suitable for application as a tape.

In addition, the method of applying the adhesive to the substrate can be used in conventional tape manufacturing such as the bar coat method, reverse roll coat method, knife coat method, roll knife coat method, gravure coat method, doctor blade coat method, and slot die coat method. Any method used can be used. In addition, it is preferable to apply the adhesive layer so that the thickness of the adhesive layer after drying and curing is 1 to 50㎛.

In order to confirm the efficiency of adhesive manufacturing when applying the manufacturing method according to the present invention, a production test run was conducted as follows.

<Synthesis Example 1>

In the colloidal polymer formation step, a reaction device equipped with a stirrer, reflux cooler, thermometer, and dropping tank was prepared to prepare the adhesive composition. Composition A was prepared by adding 110 g of vinyl acetate monomer, 15 g of acrylic acid, and 180 g of ethyl alcohol to the reaction device, and 0.5 g of Azobisisobutyronitrile (AIBN) was added to the composition A as a polymerization initiator. The reaction was initiated by raising the temperature to 80°C, and the maintenance reaction was carried out for 30 minutes.

In the adhesive development functional polymer formation stage, 15 g of acrylic acid monomer, 336 g of 2-Ethyl hexyl acrylate monomer, 144 g of n-butyl acrylate monomer, and ethyl alcohol Composition B was prepared by mixing 120 g of alcohol), the composition B was placed in a dropping tank, and 0.5 g of AIBN (Azobisisobutyronitrile) as a polymerization initiator was mixed thereto and added dropwise for 90 minutes. After the dropwise addition, a maintenance reaction was carried out for 60 minutes, and then composition C prepared by mixing 60g of ethyl acetate and 0.5g of the polymerization initiator AIBN was added dropwise for 30 minutes until the reaction was completed. After cooling, 50 g of ethyl acetate was added to terminate the reaction. The viscosity of the adhesive resin (A) obtained after completion of the reaction was 6,000 cPs, and the non-volatile content was 60%.

As the reaction progresses, a difference in solubility occurs as the side chain of the adhesive polymer increases, and association occurs to maintain dispersion stability. Surrounding oligomers continue to associate inside the colloid due to the difference in solubility, and the reaction combines to create a high molecular weight. It was observed that the transparent solution gradually became opaque.

<Synthesis Example 2>

The reaction was performed in the same manner as Synthesis Example 1, and the composition ratio used was Composition A; 110 g of vinyl acetate monomer, 10 g of acrylic acid monomer, 180 g of ethyl alcohol, 0.5 g of Azobisisobutyronitrile (AIBN), composition B; Adhesive resin (B) was obtained in the same manner except that 10g of acrylic acid monomer, 336g of 2-ethylhexyl acrylate monomer, 144g of n-butylacrylate monomer, 120g of ethyl alcohol, and 0.5g of AIBN (Azobisisobutyronitrile) were used. The viscosity of the adhesive resin (B) was 5,000 cPs, and the non-volatile content was 60%.

<Synthesis Example 3>

The same reaction device as Synthesis Example 1 was prepared, and 620 g of an acrylic mixture consisting of 110 g of vinyl acetate monomer, 30 g of acrylic acid monomer, 336 g of 2-ethylhexyl acrylate monomer, and 144 g of n-buty acrylate monomer was prepared, and 30% of the prepared acrylic mixture was added. 0.5 g of polymerization initiator (AIBN) and solvent (380 g of ethyl acetate, 50 g of toluene) were added to the reactor and heated to 80°C to initiate the reaction. A maintenance reaction was carried out for 30 minutes, and then 70% of the acrylic mixture was added to the reactor. 0.5 g of polymerization initiator and 170 g of solvent (ethyl acetate) were added to the dropping tank and added dropwise for 90 minutes. After the dropwise addition was completed, a maintenance reaction was performed for 60 minutes, and then 60 g of solvent (ethyl acetate) was added to the dropping tank and added for 30 minutes. The dropwise addition was continued for several minutes, and the reaction was cooled until the reaction was completed. The reaction was terminated by adding 50 g of solvent (ethyl acetate). The viscosity of the adhesive resin (C) obtained after the reaction was completed was 5000 cPs, and the The volatile matter was 40%.

<Synthesis Example 4>

The water-based adhesive SA -660 from Soosan Polymer Co., Ltd., which was released and sold as an existing prototype, was used. The viscosity of the adhesive resin (D) was 5,000 ± 1,000 cPs, and the non-volatile content was 60%.

<Synthesis Example 5>

The reaction was carried out in the same manner as in Synthesis Example 3, the amount of acrylic monomer was the same, and the amount of solvent (ethyl acetate) was reduced by 500 g to obtain an adhesive resin with 60% non-volatile content. However, due to gelation of the monomers in the middle of the reaction, the final result was was not obtained and the reaction was terminated.

<Synthesis Example 6>

The reaction was performed in the same manner as Synthesis Example 3, the amount of acrylic monomer was the same, and the amount of solvent (ethyl acetate) was reduced by 320 g to obtain an adhesive resin with 50% non-volatile content. However, due to gelation of the monomers in the middle of the reaction, the final The reaction was terminated without obtaining any results.

In addition, as a result of Synthesis Examples 5 and 6, it was found that the existing polymerization method, solution polymerization, could not produce adhesive resin with 50% or 60% non-volatile content.

The composition ratios for the colloidal polymer formation step and the adhesive function-expressing polymer formation step in Synthesis Examples 1 to 6 are shown in Table 3. In Table 3, the unit is g.

	Synthesis Example 1	Synthesis Example 2	Synthesis Example 3	Synthesis Example 5	Synthesis Example 6
vinyl acetate	110	110	110	110	110
acrylic acid	30	20	30	30	30
2-ethylhexyl acrylate	336	336	336	336	336
n-butylacrylate	144	144	144	144	144
ethyl alcohol	300	300
Ethyl acetate	100	110	850	350	530
toluene			50	50	50
Solid content (%)	60	60	40	-	-
Viscosity (cPs)	6,000	5,000	5,000	-	-

In addition, as a result of measuring the viscosity change in each reaction stage in Synthesis Examples 1 to 6, as shown in FIG. 3, it can be confirmed that the viscosity change in the first stage reaction and the second stage reaction proceeds gently under appropriate reaction conditions. there was. This result suggests that the process of forming a colloidal polymer through the two-step reaction according to the present invention, followed by the formation of a functional polymer that develops adhesiveness, is carried out smoothly.

<Manufacture of adhesive tape>

As shown in the table below, 100 g of adhesive resin was mixed with a tackifier and a curing agent, a tape was manufactured, and the physical properties were measured. In the table, terpene phenol resin was used as a tackifier, and an epoxy curing agent was used as a curing agent.

When manufacturing the adhesive tape, the adhesive layer was manufactured to have a thickness of 25㎛, 50㎛ PET release paper was used, and 25㎛ PET was used as the carrier. After applying the adhesive layer, a drying process was performed at 110°C for 90 seconds for No. 4 in Preparation Example 1, and a drying process was performed at 110°C for 120 seconds for No. 6 in Preparation Examples 5. Afterwards, the aging process was performed at 60°C for 48 hours. The physical properties of the adhesive tape were measured as follows. Adhesion was measured using UTM equipment according to KS T 1028. A 25 mm wide tape was pressed to a SUS304 adherend using a rubber roller (2.0 kg load) and left at room temperature for 30 minutes, and the 180° Peel value was measured at a speed of 300 mm/min. Heat resistance was measured by increasing the temperature at a rate of 10°C/10 minutes and then measuring the desorption temperature. After producing a sample of 25 Afterwards, a 500g load was applied to raise the temperature from 50°C to 10°C per 10 minutes, and the temperature during desorption was recorded.

	Example 1	Example 2	Example 3	Example 4	Comparative Example 1	Comparative Example 2	Comparative Example 3
Adhesive resin (100g)	Synthesis Example 1	Synthesis Example 1	Synthesis Example 2	Synthesis Example 2	Synthesis Example 3	Synthesis Example 3	Synthesis Example 4
Tackifier	-	15	-	15	-	15	15
hardener	One	One	One	One	One	One	One
ethyl acetate	10	10	10	10	10	10
Distilled water	-	-	-	-	-	-	10
* Tackifier: Product name T-115 Terpene Phenolic Resin, 50% Solution (in Ethyl acetate) * Hardener: Product name Tetrad-X, (2% Epoxy hardener N,N,N',-tetraglycidiyl-m-xylenediamine)

The results of measuring the physical properties of each adhesive are shown in Table 5 below.

	Example 1	Example 2	Example 3	Example 4	Comparative Example 1	Comparative Example 2	Comparative Example 3
Room temperature adhesion (gf/25㎜)	2,228	2,585	2,053	2,274	2,029	2,348	1,246
Heat resistance (℃)	150 or more	150 or more	150 or more	150 or more	140	150 or more	100

In the adhesives (Synthesis Examples 1 and 2) using the adhesive manufacturing method of the present invention, the coating viscosity was reached while using a small amount of organic solvent as shown in Examples 1 to 4, and the room temperature adhesive strength was all 2,000 gf/25 mm or more. indicated. In addition, it was evaluated to exhibit high heat resistance and stable adhesive strength even at high temperatures. These results show that the physical properties are superior to those of Synthesis Examples 5 and 6 synthesized by the existing solution polymerization method. When the adhesive composition according to the present invention is applied to an adhesive tape, it is an adhesive composition with increased non-volatile content, and is superior to existing products. This suggests that although the process time has been reduced, better characteristics can be achieved.

Although the present invention has been described with reference to preferred embodiments as described above, it is not limited to the above embodiments and various modifications and modifications may be made by those skilled in the art without departing from the spirit of the present invention. Change is possible. Such modifications and variations should be considered to fall within the scope of the present invention and the appended claims.

Claims (5)

1. A method of producing an adhesive using a low-carbon emission process comprising an adhesive resin, a polymerization initiator, a low-boiling point solvent, and a curing agent,

   The adhesive resin includes a first step of producing a colloidal polymer by mixing a hydrophilic monomer and a solvent, and a second step of mixing a hydrophobic monomer with the colloidal polymer to produce a sticky polymer. A method of manufacturing an adhesive using a low-carbon emission process, characterized in that it is manufactured.
2. In claim 1,

   A method of manufacturing an adhesive using a low-carbon emission process, wherein the low-boiling point solvent has a boiling point of 80° C. or lower.
3. In claim 1,

   A method of manufacturing an adhesive using a low-carbon emission process, characterized in that the adhesive has a non-volatile matter (NVM) content of 50% by weight or more.
4. In claim 1,

   A method of manufacturing an adhesive using a low-carbon emission process, characterized in that the adhesive has a viscosity of 20 to 200 kcps.
5. A method of manufacturing an adhesive tape, comprising the step of coating a substrate with an adhesive manufactured using the method for producing an adhesive according to claim 1.

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