KR20240009199A - Electronic Coomponents using Hot-melt film - Google Patents

Abstract

The present invention relates to electronic components using recycled hot melt. Specifically, to reduce environmental pollution and prevent resource waste, bio-based thermoplastic polyurethane (TPU) is synthesized and manufactured using the same. Regarding electronic components, it not only has excellent tensile strength at high temperatures and tensile strength at low temperatures required for manufacturing electronic or electrical components, especially circuit boards used in monitors, etc., but also has excellent cold resistance, high temperature stability, and heat resistance. It is superior to hot melt.

Description

Electronic components using recycled hot melt {Electronic Coomponents using Hot-melt film}

The present invention relates to electronic components using recycled hot melt. Specifically, to reduce environmental pollution and prevent resource waste, bio-based thermoplastic polyurethane (TPU) is synthesized and manufactured using the same. Regarding electronic components, it not only has excellent tensile strength at high temperatures and low temperatures required for manufacturing electronic components, especially circuit boards used in monitors, etc., but is also superior to existing hot melts in terms of cold resistance, high temperature stability, and heat resistance. great.

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. Specifically, in order to reduce environmental pollution and prevent resource waste, a biomass-based thermoplastic polyurethane (TPU) hot melt adhesive has been developed to be used in electronics. The purpose is to provide hot melt adhesives and electronic components to which they are applied that can meet the environmentally friendly requirements of the circuit board industry used in parts, especially monitors, etc., as well as heat resistance and toughness.

On the one hand, the present invention

In hot melt for electronic components,

Bio-fatty acid-based polyester polyol;

Isosorbide-based isocyanate; and

The purpose is to provide electronic components using recycled hot melt, characterized in that a hot melt composed of thermoplastic polyurethane containing a chain extender is applied.

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.

In addition, the recycled hot melt according to the present invention not only has excellent adhesion, but also exhibits excellent physical properties in cold resistance, heat resistance, and thermal shock strength, so it requires more difficult cold resistance, heat resistance, resistance at high and low temperatures, and corrosion resistance compared to general-purpose hot melt. It can be used as an effective hot melt in the field of electronic device components, such as for bonding electronic or electrical components, for example, for attaching elements to a circuit board.

Figure 1 is a diagram showing the specific gravity and MI by BIO content of a hot melt according to an embodiment of the present invention.
Figure 2 shows a recycled hot melt manufactured according to an embodiment of the present invention.
Figure 3 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 4 is a graph showing the results of measuring the tensile properties of a TPU resin synthesized according to an embodiment of the present invention.

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

The present invention relates to electronic components using recycled hot melt,

In hot melt for electronic components,

Bio-fatty acid-based polyester polyol;

Isosorbide-based isocyanate; and

It is characterized in that a hot melt composed of thermoplastic polyurethane containing a chain extender is applied.

The recycled hot melt according to the present invention not only has excellent tensile strength at high temperatures and low temperatures required for manufacturing electronic components or electrical components, especially circuit boards used in monitors, etc., but also has excellent cold resistance, high temperature stability, and heat resistance. Since it is superior to existing hot melt compositions, it can be effectively used as a hot melt for electronic components.

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 recycled 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.

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.

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 At ¹ , -C=O- among the urethane groups, and -CN- peak among the urethane groups at 1310 cm ^-1 were observed, confirming that bio-based TPU was successfully synthesized.

An upper hot melt film with a thickness of 200㎛ prepared by mixing and molding 1 part by weight of stearyldimethylbenzylammonium chloride, an antistatic agent, with 100 parts by weight of polyurethane resin, and a lower hot melt film with a thickness of 200㎛ made of 100 parts by weight of polyurethane resin. By stacking each other, a hot melt film with a two-layer structure was manufactured.

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 1).

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 a normal film was formed under the extrusion temperature condition of 120°C (see Figure 2).

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 3).

Experimental Example 4:

The hot melt prepared in the above example was melted at 200°C to produce a specimen in which a PCB board and an aluminum electrolyte capacitor were bonded, and then cooled to room temperature. The manufactured specimen was left in a thermostat maintained at -40°C for 100 hours, then taken out and observed for cracks and lifting at the joint of the specimen.

As a result, the hot melt according to the present invention did not cause any cracking or lifting even at -40°C. Therefore, it was confirmed that the hot melt of the present invention has cold resistance up to at least -40°C.

Experimental Example 5:

The hot melt according to the present invention was melted at a temperature of 200°C, applied to the adhesive surface of the prepared adherend within 5 seconds, and left at room temperature for 1 hour. The adherend was manufactured by overlapping two steel specimens with a length of 100 ± 0.5 mm and a width of 25 ± 0.5 mm by about 12.55 ± 0.5 mm, and applying a hot melt adhesive between them. After leaving the specimen in a dry oven at 80℃ or 25℃ for 1 hour, take it out and pull it at a tensile speed of 10 mm/min using a push-pull gauge within 10 seconds until the specimen is destroyed. The maximum load when the specimen was broken by pulling was measured.

As a result, the hot melt of the present invention had a significantly high tensile strength of 17 to 20 kgf/cm ² at 80°C, and the tensile adhesive strength at 25°C was also high at 28 to 33 kgf/cm ² , making it effective not only at low temperatures but also at high temperatures. It was confirmed that it had excellent properties in terms of tensile adhesive strength (see Figure 4).

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 (3)

In hot melt for electronic components,
Bio-fatty acid-based polyester polyol;
Isosorbide-based isocyanate; and
Electronic components using recycled hot melt, characterized in that a hot melt composed of thermoplastic polyurethane containing a chain extender is applied. The electronic component using recycled hot melt according to claim 1, wherein the content of biomass, which is the bio fatty acid, is more than 50% of the total 100%. The electronic component using recycled hot melt according to claim 1, wherein the hot melt has an adhesive strength of 2.5 kgf/cm or more.