KR20240009619A - Manufacture method of Eco-Friendly Hot-melt film - Google Patents

Abstract

The present invention relates to an eco-friendly hot melt manufacturing method. Specifically, in order to reduce environmental pollution and prevent resource waste, thermoplastic poly urethane (TPU) can be prepared according to the type of bio-based polyol and various types of chain extenders. ) and a method of producing an eco-friendly hot melt adhesive using it.

Description

{Manufacture method of Eco-Friendly Hot-melt film}

The present invention relates to an eco-friendly hot melt manufacturing method. Specifically, in order to reduce environmental pollution and prevent resource waste, thermoplastic poly urethane (TPU) can be prepared according to the type of bio-based polyol and various types of chain extenders. ) and a method of producing an eco-friendly hot melt adhesive using it.

Hot-melt is a solvent-free adhesive with 100% solid content at room temperature. When used, it is an adhesive that develops adhesive power by heating and melting, applying to various adherends, and then cooling and solidifying. It is used in the home appliance field as well as packaging, bookbinding, and wood. It is widely used in fields such as processing. Hot melt is heated and melted at a high temperature and cooled immediately after application, enabling continuous operation. It does not generate volatile matter, making it simple and even to control the application thickness. There is no risk of fire. It is generally used for base polymers, adhesive resins, and waxes. It is composed of three main ingredients, and antioxidants, plasticizers, and flame retardants are mixed and used as needed.

However, existing hot melt adhesives are commonly used in packaging, bookbinding, woodworking, electrical and electronic fields, etc., and have not achieved satisfactory effects in terms of heat resistance, cold resistance, adhesion, and thermal shock strength for special application to electronic components. .

In particular, in the case of electronic or electrical components, the demand of which has recently been rapidly increasing, a hot melt with desirable characteristics is required to attach the electronic components to a printed circuit board (PCB). A PCB is manufactured by covering a paper epoxy or glass epoxy board with a copper film, printing the necessary circuits, and removing the remaining parts, and many IC and other components are attached. Therefore, hot melts applied to electronic or electrical components not only have desirable electrical properties, such as a low tendency to decompose the materials that make up other components, and high resistance, but also do not damage other elements of the electronic components. In order to do this, it must have a sufficiently low melting point to allow the adhesive composition to be applied at low temperatures, but must have sufficient high temperature resistance so that its bonding strength is not broken even at the high temperatures required for assembly of parts and subsequent processes.

However, to date, most hot melt compositions have been mainly used in the paper or nonwoven industries or have been developed only for adhesion to automobile interior materials, etc., and only a very small number of special hot melt compositions with improved physical properties for application to electronic or electrical components have been developed. Therefore, only some multinational companies have the technology for this.

As can be seen from the examples above, the application of hot melt films is increasing, and while the development of these technologies and materials is very important, the need for environmental considerations is also increasingly emphasized.

The use of biomass that can grow sustainably is becoming important to solve the problems of global warming and oil resources. As environmental issues have recently grown, international environmental and trade regulations are being implemented to reduce the environmental load. In the case of automobiles, these regulations are being implemented. As a countermeasure, the environmental management system is being improved and strengthened to build safe and comfortable eco-friendly vehicles and workplaces, and the demand for the use of plastics using biomass for parts and interior materials as well as fuel is increasing.

Korean Patent No. 10-0400876

The present invention is intended to solve the above-mentioned environmental problems, and specifically, to reduce environmental pollution and prevent resource waste, a biomass-based thermoplastic polyurethane (TPU) hot melt adhesive was developed to be used in automobiles. The purpose is to provide an eco-friendly hot melt adhesive that can meet the industry's eco-friendly requirements while also meeting heat resistance and toughness.

On the one hand, the present invention

(i) heating and stirring 60 to 70% by weight of bio fatty acid-based polyester polyol;

(ii) reacting the polyol with 20 to 30% by weight of isosorbide-based isocyanate and a catalyst; and

(iii) lowering the temperature and then reacting with 5 to 10% by weight of a chain extender to produce thermoplastic polyurethane,

A first melting point peak found at 40°C to 60°C during differential scanning calorimetry (DSC) thermal analysis; And a second melting point peak found at 100°C to 110°C, characterized in that it provides an eco-friendly hot melt manufacturing method.

According to the present invention, the bio content of existing products can be increased by 1.5 to 2 times by using bio-isocyanate, and when the product is disposed of, CO ₂ emissions can be reduced by more than 60% compared to petroleum products. In addition, because it is processed with a hot melt film, it is easy to recycle scrap or broken film generated during the process, thereby reducing costs in the process and recycling resources.

Figure 1 shows the synthesis mechanism of an eco-friendly hot melt according to an embodiment of the present invention.
Figure 2 is a diagram showing the specific gravity and MI by BIO content of hot melt according to an embodiment of the present invention.
Figure 3 shows an eco-friendly hot melt manufactured according to an embodiment of the present invention.
Figure 4 is a diagram showing the tensile strength and elongation by BIO content of the hot melt according to an embodiment of the present invention.
Figure 5 is a graph showing the results of thermal analysis of hot melt using differential scanning calorimetry (DSC) according to an embodiment of the present invention.
Figure 6 is a diagram showing the FT-IR spectrum results of the TPU resin according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail.

The present invention relates to an eco-friendly hot melt manufacturing method,

(i) heating and stirring 60 to 70% by weight of bio fatty acid-based polyester polyol;

(ii) reacting the polyol with 20 to 30% by weight of isosorbide-based isocyanate and a catalyst; and

(iii) lowering the temperature and then reacting with 5 to 10% by weight of a chain extender to produce thermoplastic polyurethane; It is characterized by including.

In one embodiment of the present invention, heat of 80 to 90° C. is applied in step (i).

In one embodiment of the present invention, in step (ii), the NCO content of the reactant is confirmed through dibutylamine back-titration (DBA) to determine the next step.

In one embodiment of the present invention, in step (iii), the reaction is performed until no unreacted NCO exists.

The present invention is a high-content polyester polyol with excellent heat resistance, elasticity, and tensile properties based on bio fatty acid-based polyester polyol, isosorbide isocyanate, and chain extender. It's about eco-friendly hot melt.

In one embodiment of the present invention, the hot melt is characterized in that it is composed of biomass-based thermoplastic polyurethane (Thermoplastic Poly Urethane, TPU).

For the physical properties of the TPU, the equivalence ratio of functional groups can be adjusted, and various thermoplastic polyurethanes can be synthesized depending on the ratio of the polyol used and the ratio of each type of chain extender (see Figure 1).

In one embodiment of the present invention, the content of biomass, which is the bio fatty acid, is preferably 40% or more of the total 100%, and more preferably 60% or more.

In one embodiment of the present invention, the eco-friendly hot melt has a first melting point peak found at 40°C to 60°C during thermal analysis by differential scanning calorimetry (DSC); and a second melting point peak found between 100°C and 110°C.

Hereinafter, the present invention will be described in more detail through examples. These examples are only for illustrating the present invention, and it is obvious to those skilled in the art that the scope of the present invention is not limited to these examples.

Example 1:

The polyol from which moisture was removed was added to a 500 ml four-neck reactor equipped with a stirrer, condenser, and nitrogen inlet, and stirred uniformly at 80°C for 1 hour. After that, the isocyanate was dropped, a catalyst was added, and the reaction was performed. The NCO content of the reactant was confirmed through the dibutylamine back-titration (DBA) method, and when the theoretical NCO content was reached, the next reaction was performed. The temperature was lowered to 50°C and the reaction proceeded while dropping the chain extender to synthesize thermoplastic polyurethane. The reaction was completed when all unreacted NCO disappeared. FT-IR was measured to confirm the structure of the polymer produced in each reaction step and the structure of the finally synthesized thermoplastic polyurethane.

As a result of measuring FT-IR according to the reaction time, it was confirmed that the NCO characteristic peak at 2270cm ^-1 disappeared as time passed, and -NH peak, 1700~1730cm ^-1 among urethane groups around 3300cm ^-1 and 1530cm ^-1 The -C=O- peak among the urethane groups at ¹ and the -CN- peak among the urethane groups at 1310 cm ^-1 were observed, indicating that bio-based TPU was successfully synthesized (see Figure 6).

Referring to Figure 6, TA-1 is a polyol with an OH value of 38.89 mg KOH/g, TA-2 is a polyol with an OH value of 53.31 mg KOH/g, and TA-3 is a polyol with an OH value of 48.12 mg KOH/g. It is a result. Looking at the results of TA-1 and TA-2 synthesized with the same pre-polymer equivalent ratio, the tensile strength and adhesive strength of TA-1 using a polyol synthesized using a low molecular weight and one type of diol were found to be higher. indicated. In addition, as a result of synthesizing TA-3 with an increased prepolymer equivalence ratio, the physical properties were not significantly increased.

Experimental Example 1:

Research was conducted on TPU hot melt films with final bio content of 10%, 21%, 30%, and 43%.

① Bio content 10%

In order to achieve TPU with 10% bio content, three types of petroleum-based TPU raw materials from D Company were mixed with TPU raw materials with 25% bio content.

[Table 1]

② Bio content 21%

We used TPU raw material with 25% Bio content received from Company D. (※ Product with different physical properties from the Bio TPU 25% product (8085AP) above)

③ Bio content 30%

We used TPU raw material with 33% bio content received from Company D.

④ Bio content 43%

Using TPU raw materials with a bio content of 47.33% received from the Korea Shoe and Leather Research Institute, raw materials were mixed to produce a TPU hotmelt film with a final bio content of 43%.

To manufacture the compounded TPU resin into a film, various additives shown in Table 2 below were additionally added. When producing hot melt adhesive film using the blown extruder method, the role of slip agent among additives is more important, and a higher proportion of slip agent is added than with the T-Die method.

[Table 2]

To evaluate the physical properties of the four types of resins made according to the above mixing ratio according to the Bio content, density and melt flow values were measured using an M.I (Melt Indexer) meter. Experimental measurements were conducted five times for each property evaluation item, and the final result was derived as the average value (see Figure 2).

Experimental Example 2:

In order to check whether the resins formed films according to the four types of Bio content, a film production experiment was conducted using the blown extruder method under different extrusion conditions. When producing a film, the extrusion condition factors include extrusion speed and extrusion temperature. The experiment was conducted by changing the extrusion temperature condition, which has a greater influence on the quality of the film, to 125 to 145 °C. (Extrusion speed is based on 8m/min.)

① Bio content 10%

At the extrusion temperature of 125℃, it was confirmed that gel was formed on the film, which occurs when the extrusion temperature is low, and it was confirmed that the gel formation problem did not occur when the extrusion temperature was raised to 135℃ or higher. When the extrusion temperature increased above 140°C, it was visually confirmed that the discharge amount of raw resin increased and the film thickness became thicker and more unstable. As a result of film manufacturing using raw material resin with a bio content of 10%-2, it was confirmed that optimal film formation was achieved under extrusion temperature conditions of 135℃~140℃.

② Bio content 21%

There was a problem with gel formation on the film at extrusion temperatures of 115 and 120℃, and no gel formation was seen when the extrusion temperature was raised above 125℃. It was confirmed that stretching improves as the extrusion temperature increases. However, at extrusion temperatures above 135°C, workability becomes unstable due to an increase in the discharge amount of raw resin, and the winding does not work properly due to uneven tension when winding the film, resulting in the problem of wrinkles forming in the film. occurred. As a result of a film manufacturing experiment using raw material resin with 21% bio content, it was confirmed that normal film formation occurred under extrusion temperature conditions of 125℃ and 130℃.

③ Bio content 30%

When the extrusion temperature was low, there was a problem with gel formation on the film, and at temperatures lower than 130°C, a gel formation problem occurred due to unmelting. As a result of a film manufacturing experiment using raw material resin with 30% bio content, it was confirmed that normal film formation occurred under the extrusion temperature condition of 135°C. The reason why the optimal extrusion temperature condition is higher compared to the raw material resin with 21% bio content could be predicted by the hardness of the product physical properties that affect the extrusion temperature, and the actual hardness of the 21% bio TPU product (Shores A 75~80) compared to the product with 30% bio content It can be seen that the hardness (Shores A 90-95) is high.

④ Bio content 43%

It was confirmed that when the extrusion temperature exceeds 125°C, flowability increases and workability is adversely affected, tension becomes inconsistent, and winding defects occur. As a result of a film manufacturing experiment using a raw material resin with a bio content of 43%, it was confirmed that normal film formation occurred under the extrusion temperature condition of 120°C (see Figure 3).

Experimental Example 3:

Confirm the processing technology of existing petroleum-based TPU hot melt film, and verify product performance (thickness, tensile strength, tensile elongation) according to processing technology and conditions for each bio content (10%, 21%, 30%, 43%). Through this, optimal processing conditions were derived. Previously, processing conditions were derived by referring to the optimal extrusion temperature conditions for each mixing ratio, and an in-house physical property test was conducted to verify the performance of the TPU hot melt film product. Experimental measurements were conducted five times for each physical property evaluation item (see Figure 4).

Experimental Example 4:

Thermal analysis was performed on the hot melt composition according to the present invention using differential scanning calorimetry (DSC). The results are as shown in Figure 5.

With reference to this, the hot melt composition according to the present invention may include a first melting point peak found at 40°C to 60°C and a second melting point peak found at 100°C to 110°C. Through the first melting point peak, it can be seen that the hot melt composition has excellent flexibility and processability. Meanwhile, through the second melting point peak, it can be seen that the hot melt composition has crystallinity and is stably melted only at a certain temperature, and that it cools quickly when it exceeds this melting temperature. Therefore, using the hot melt composition can ensure the adhesion stability of automobile interior materials.

As the specific parts of the present invention have been described in detail above, it is clear to those skilled in the art that these specific techniques are merely preferred embodiments and do not limit the scope of the present invention. do. Anyone skilled in the art to which the present invention pertains will be able to make various applications and modifications within the scope of the present invention based on the above contents.

Accordingly, the actual scope of the present invention will be defined by the appended claims and their equivalents.

Claims (5)

(i) heating and stirring 60 to 70% by weight of bio fatty acid-based polyester polyol;
(ii) reacting the polyol with 20 to 30% by weight of isosorbide-based isocyanate and a catalyst; and
(iii) lowering the temperature and then reacting with 5 to 10% by weight of a chain extender to produce thermoplastic polyurethane,
A first melting point peak found at 40°C to 60°C during differential scanning calorimetry (DSC) thermal analysis; and a second melting point peak found at 100°C to 110°C. The method of claim 1, wherein in step (i), heat is applied at a temperature of 80 to 90° C. The method of claim 1, wherein in step (ii), the NCO content of the reactant is confirmed through the dibutylamine back-titration (DBA) method to determine the next step. The method of claim 1, wherein in step (iii), the reaction is carried out until no unreacted NCO exists. The method of claim 1, wherein the hot melt has an adhesive strength of 2.5 kgf/cm or more.