KR20020032748A - hot-melt adhesive for electronic components - Google Patents

Abstract

PURPOSE: Provided is a hot melt composition having property useful for adhesion of electronic or electric component, which has excellent tensile strength at high temperature and low temperature, and better freezing resistance, stability to high temperature and heat resistance than existing hot melt composition. CONSTITUTION: The hot melt composition for electronic component comprises 10-40 wt% of polyolefin wax, 5-15 wt% of polypropylene, 10-50 wt% of butene-propylene copolymer, 2-40 wt% of dicyclopentadiene and 0.1-5 wt% of polybutadiene. Therefore, the composition can be effectively used as hot melt for electronic component.

Description

Hot-melt composition for electronic components

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to hot-melt compositions for electronic components, specifically 10-40% by weight of polyolefin wax, 5-15% by weight of polypropylene, and 10-butene-propylene copolymer. It relates to 50% by weight, 2 to 40% by weight of dicyclopentadiene (DCPD) resin, and 0.1 to 5% by weight of polybutene (polybutene) relates to a hot melt composition for bonding electronic components.

Hot-melt is a solvent-free adhesive with a solid content of 100% at room temperature.It is applied to various adherends by heating and melting when used, and expressing adhesive strength by cooling and solidifying it. It is widely used in the field of processing. The hot melt is heated and melted at a high temperature and cooled immediately upon application, thereby allowing continuous operation. Since no volatiles are generated, the adjustment of the coating thickness is simple and uniform, and there is no risk of fire. It consists of three components as main components, and antioxidant, a plasticizer, a flame retardant, etc. are mix | blended and used as needed.

The main component is ethylene vinyl chloride copolymer (ethylene vinyl chloride copolymer, EVA), the most common polyamide, polyester, atactic polypropylene, etc., rosin-based resin, petroleum It has been produced by mixing resins and the like, and mixing waxes, antioxidants, inorganic fillers, reversible agents and the like.

The exterior has the shape of pallet, block, etc., and it is appropriately selected according to the usage and the place of use.As it adheres soon after the temperature decreases, the adhesion is usually within 1 second and continuous work is possible. It can also be applied to difficult vertical and inclined planes. In addition, there is an advantage that can be used for a material that can not be bonded by ordinary adhesives such as polyethylene and polypropylene, reaching almost the highest strength after cooling.

However, the existing hot melt adhesives are commonly used in packaging, bookbinding, wood processing, electrical and electronic fields, and have not been satisfactory in heat resistance, cold resistance, adhesiveness, and thermal shock strength for application to electronic parts. .

In particular, in the case of an electronic component or an electronic component that is rapidly increasing in demand, hot melts having desirable characteristics are required to attach electronic components to a printed circuit board (PCB). The PCB is manufactured by printing a necessary circuit by coating a copper film on a paper epoxy or glass epoxy substrate, and removing other portions, and a large number of IC and other components are attached. Therefore, the hot melt applied to the electronic component or the electrical component is less prone to decomposing desirable electrical properties, for example, materials constituting the other components, and does not damage other components of the electronic components as well as electrical properties such as high resistance. In order to apply the adhesive composition at a low temperature, it must have a sufficiently low melting point, but have sufficient high temperature resistance such that the bonding force is not broken even at the high temperature required for the assembly and subsequent processing of the part. In particular, there is no corrosion resistance to copper, high low-temperature shear strength, high creep resistance at high temperatures, and resistance at low temperatures as low as -40 ° C. Development of an effective hot melt composition such as cold resistance, heat resistance and thermal shock strength, as well as basic adhesiveness when used in electronic components, especially in monitors where long-term operating conditions are required and high frequency operation requires deformation due to temperature rise. This has been urgently needed.

However, to date, most hot melt compositions have been developed mainly for use in the paper or nonwovens industry, or for adhesion to automotive interior materials, and only a few have been developed for special hot melts with improved properties for application to electronic or electrical parts. Only a few multinational companies have the skills to do this.

As a representative example, 3M (Minnesota Mining and Manufacturing Company, USA), which occupies most of the hot melt market for electronic components, develops and sells various types of hot melts. Among them, amorphous polypropylene 10 ~ An adhesive has been developed that consists of 70% by weight, 2 to 70% by weight of styrene-diene block copolymer, a styrene-based thermoplastic elastomer, 1 to 35% by weight of adhesive, and up to 24% by weight of wax components (Korean Patent Publication No. 96- 8484). Since it is known that the addition of amorphous polypropylene to EVA-based hot melts can improve heat dissipation, heat melting, weather resistance, and resistance at high and low temperatures (Japanese Patent Application Laid-Open No. 60-120775) Many studies have been conducted on hot melts using polypropylene. The 3M patent is one of them, and the 3M patent is characterized by using amorphous polypropylene as a base, but adding styrene-based block copolymer rubber thereto to improve physical properties. However, styrenic block copolymer rubbers have difficulty in handling and using due to their poor thermal shock resistance and mechanical properties, high viscosity, and low ability to wet the substrate, depending on the type and content of the styrene-based block copolymer rubber.

Accordingly, the present inventors have conducted research to develop a hot melt having a new composition suitable for use in bonding electronic parts or electrical parts and having desirable heat resistance, cold resistance, and resistance at high and low temperatures. The present invention was completed by revealing that a polymelt wax and a polyethylene wax were used as a base polymer together with propylene and a polyolefin wax was mixed as a polyolefin wax, and a hot melt having a polybutene added thereto met the above requirements.

It is an object of the present invention to provide a hot melt composition of a new composition having properties useful for the adhesion of electronic or electrical components. Specifically, the present invention has no corrosiveness to copper, has high low-temperature shear strength, high creep resistance at high temperature, and low temperature at about -40 ° C., so that the present invention can be effectively used for bonding electronic components and electrical components. It is an object to provide a hot melt composition.

In order to achieve the above object, the present invention is 10 to 40% by weight of polyolefin wax, 10 to 50% by weight of butene-propylene copolymer, 5 to 15% by weight of polypropylene, dicyclopentadiene (DCPD) Provided is a hot melt composition for an electronic part or an electric part, comprising 2 to 40 wt% of a resin and 0.1 to 5 wt% of a polybutene.

As the polyolefin wax component, it is preferable to use polypropylene wax or polyethylene wax, and to improve heat resistance and melt viscosity by using polyolefin wax. If the wax content is too small, it is difficult to control the melt viscosity, the workability is poor, and the delamination phenomenon occurs. In addition, when too many waxes are used, there is a problem of deterioration in adhesive strength and low temperature characteristics.

More preferably, 5 to 20 weight% of polypropylene wax and 5 to 20 weight% of polyethylene wax are included.

The polypropylene wax preferably has a molecular weight of about 1000 to 5000, and the polyethylene wax preferably has a molecular weight of about 1000 to 3000. By using a polyolefin wax, workability can be improved by improving the set time of the adhesive composition, changing the viscosity to improve the composition handling properties.

The polypropylene and butene-propylene copolymers included as base polymers are added to impart flexibility to the adhesive and to improve adhesion. The butene-propylene copolymer preferably has a molecular weight of about 1000 to 50000. Too high content of the polypropylene and butene-propylene copolymers as the base polymer results in too low a softening of the final composition, and too low content of the polypropylene and butene-propylene copolymer. It is preferable to use atactic polypropylene as the polypropylene that can be used in the above, but may also include a small amount of isotactic or syndiotactic polypropylene.

In the preferred embodiment of the present invention, the physical properties were compared using a hot melt having a composition similar to the composition of the present invention as a comparative example, except that the butene-propylene copolymer and polybutene were not included. It was expected that the problem is expected to have a cold resistance of about -27 ℃ compared to the cold resistance of the present invention hot-melt composition reaching -40 ℃, the tensile adhesive strength at high and low temperatures also compared to the composition of the present invention 1 / Only two were surveyed. Therefore, it can be seen that it is important to add an appropriate amount of butene-propylene copolymer in order to have desirable cold resistance, ease of operation and resistance to high temperature and low temperature of the composition of the present invention.

In the hot melt composition of the present invention, another component is polybutene, which serves to improve the physical properties and tackiness of the overall hot melt composition, as well as provide essential insulation for use in bonding electronic parts and electrical parts.

DCPC resin is preferably used to increase the compatibility of the above components. DCPC (dicyclopentadiene) resin preferably has a molecular weight of about 1000 to 50000, the addition thereof can achieve the desired improvement in compatibility and adhesion.

In addition to the components mentioned above, additives such as antioxidants, flame retardants, fillers, colorants, stabilizers and the like may be included in the composition according to methods known in the art for producing hot melts, depending on the properties and uses of the desired hot melt composition. have. For example, calcium carbonate or talc may be used as a filler, paraffinic or naphthenic hydrocarbon oil may be used as a plasticizer, and halogen, phosphate, or the like may be used as a flame retardant, and these additives are generally inert and substantially a major component. It does not affect the properties of the phosphorus base polymer, the wax and the tackifier, and can be used according to a known general method.

The method for preparing the hot melt adhesive composition may be prepared by mixing the above-described components and preferred additives in a conventional manner to completely melt. In order to obtain a more uniform composition, it can be prepared according to a known method such as high shear mixing, and in general, the wax component and polypropylene, base polymer, DCPC resin and polybutene in a stirring tank maintained at a temperature of 150 to 250 ° C. In order to be melted sufficiently to add a plasticizer, a colorant, an oxidant stabilizer and a flame retardant, etc., if necessary, can be prepared in the form of a cooling chip using a conveyor belt or the like.

In the embodiment of the present invention, a hot-melt composition having various composition ratios within the above-mentioned composition range and a composition which does not include butene-propylene copolymer and polybutene as a comparative example, are prepared at a viscosity, high temperature and low temperature The properties such as tensile shear strength and cold resistance were investigated.

First, hot melts having various composition ratios are prepared and melted at 180 to 220 ° C. to prepare specimens, and then cooled to room temperature. As a result of examining the cold resistance by leaving the produced specimen in a thermostat maintained at -40 ° C. for 100 hours and checking the occurrence of cracks and the degree of lifting, the hot melt composition of the present invention exhibited no cracking and lifting phenomenon at -40 ° C. Although it did not occur, it showed high cold resistance, but the hot melt of the comparative example which does not contain butene-propylene copolymer and polybutene shows cold resistance only about -27 degreeC, and the hot melt of this invention is applied to an electronic component or an electric component in cold resistance. It was found to be suitable for cold resistance. On the other hand, after leaving the fabricated specimens at 80 ℃ and 25 ℃ dry oven for 1 hour, and using the push-pull gauge within 10 seconds to measure the maximum load until the specimen is destroyed, as a result Tensile strength was about 17-20 kgf / cm ² , 9.3 kgf / cm ² , and significantly higher than the hot melt of the comparative example, and tensile strength at 25 ° C was also 28-33 kgf / cm ² , about 13.5 kgf / cm ² . About 2 times higher than the hot melt of the comparative example of cm ² , it was confirmed that the hot melt of the present invention has high resistance at high and low temperatures. Viscosities measured at 180 ° C. were also found to be relatively suitable for operation at 5350-5850 cps / 180 ° C.

The hot melt composition of the present invention can be used for binding electronic components or electrical components, for example, it can be preferably used for the purpose of attaching elements, etc. to electronic products, especially circuit boards used in monitors and the like.

Hereinafter, the present invention will be described in detail by way of examples.

However, the following examples are merely to illustrate the invention, but the content of the present invention is not limited to the following examples.

Example 1 Preparation of Hot Melt Composition 1

11 kg of polypropylene wax, 20 kg of polyethylene wax, and 5 kg of polypropylene were charged into a 500 liter hot-melting stirring tank, and stirred at a speed of 80 rpm at a temperature of about 200 ° C. After melting the wax component and the polypropylene while maintaining the temperature inside the tank at 150 to 250 ° C, 45 kg of a butene-propylene copolymer having a molecular weight of 1,000 to 50,000 was mixed with the base polymer. After stirring for about 2 hours to completely melt the components, about 19 kg of DCPD (dicyclopentadiene) resin and 0.1 kg of polybutene were added and melted. After all the compounding raw materials were heated and melted, they were cooled to 25 ° C. using a conveyor belt and prepared in the form of chips.

Examples 2 to 7 Preparation of Hot Melt Compositions 2 to 7

To prepare a hot melt chip in the same manner as in Example 1, varying the content of the wax component, the base polymer, the adhesive resin and the polybutene, to prepare a hot melt having various component ratios, each composition ratio is shown in Table 1 below It was.

ingredient Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Polypropylene wax 12 13 14 15 16 17 Polyethylene wax 19 18 17 16 15 14 Polypropylene 5 5 6 6 10 10 Butene-propylene copolymer 44 43 42 41 40 39 DCPD Resin 19.5 20 19 19 15 15 Polybutene 5.0 1.0 2.0 3.0 4.0 5.0

Experimental Example 1 Cold Resistance Test

The hot melt prepared in the above example was melted at 180 to 220 ° C. to prepare a specimen in which the PCB substrate and the aluminum electrolyte capacitor were bonded together, and then cooled at room temperature. After the prepared specimen was left for 100 hours in a thermostat maintained at -40 ℃, it was taken out to observe the crack (crack) and lifting of the specimen junction. As a comparative example, a hot melt composition having the composition shown in Table 2 below was used.

ingredient Comparative Example 1 Polypropylene wax 4 Polyethylene wax 30 Polypropylene 40 Butene-propylene copolymer - DCPD Resin 26 Polybutene -

As a result, the hot-melt composition of the comparative example containing no butene-propylene copolymer and polybutene exhibited cold resistance up to about -27 ° C, but cracks and lifting occurred at low temperatures of -30 ° C or lower, but in Example 1 of the present invention The hot melts of 7 to 7 did not generate any cracking or lifting phenomenon even at -40 ° C. Therefore, the hot melt of the present invention was confirmed to have cold resistance at least up to -40 ℃. The cold resistance test results are shown in Table 3 below.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Comparative Example 1 Cold resistance -40 ℃ -40 ℃ -40 ℃ -40 ℃ -40 ℃ -40 ℃ -40 ℃ -27 ℃

Experimental Example 2 Viscosity Measurement

After melting the hot melts of Examples 1 to 7 and Comparative Examples 1 and 2 at a temperature of 180 to 220 ° C., a viscosity (cps / 180 ° C.) was measured at 180 ° C. using a viscometer (Tokyo Keiki BL Type viscometer, Japan). The results are shown in Table 4 below.

Furtherance Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Comparative Example 1 Viscosity 5820 5760 5715 5670 5650 5460 5380 5120

Experimental Example 3 Tensile Adhesive Strength

The hot melts of Examples 1 to 7 were melted at a temperature of 180 to 220 ° C. and applied to the adhesive surface of the prepared adhesive within 5 seconds, and then left at room temperature for 1 hour. The adherend was fabricated by overlapping two specimens of steel length 100 ± 0.5 mm and width 25 ± 0.5 mm to about 12.55 ± 0.5 mm, and applying hot melt adhesive therebetween. After leaving the specimen in a dry oven at 80 ° C. or 25 ° C. for 1 hour, take it out and use the push-pull gauge within 10 seconds until the specimen is destroyed at a tensile speed of 10 mm / min. The maximum load when the specimen was pulled out was measured, and the results are shown in Table 5 below.

Furtherance Tensile Adhesive Strength (kgf / cm ² ) 80 ℃ 25 ℃ Example 1 17.0 28.5 Example 2 17.5 31.1 Example 3 19.2 28.6 Example 4 18.0 29.2 Example 5 18.2 32.3 Example 6 18.6 33.0 Example 7 19.1 29.1 Comparative Example 1 9.3 13.5

As can be seen from the results of the table, the hot melt of the present invention has a tensile strength of ¹⁷ to 20 kgf / cm ² at 80 ℃, significantly higher than the hot melt of the comparative example of about 9.3 kgf / cm ² , the tensile strength at 25 ℃ The adhesive strength was 28-33 kgf / cm ^{2, which} was about 2 times higher than the hot melt of the comparative example of about 13.5 kgf / cm ² , and it was confirmed that the adhesive had excellent properties not only at low temperature but also at high temperature.

The hot melt composition of the present invention not only has excellent adhesion but also exhibits excellent physical properties in cold resistance, heat resistance, thermal shock strength, and the like. Or as an effective hot melt in the field of electronic components, such as for bonding electrical components, for example for attaching elements to circuit boards.

Claims (7)

10 to 40 weight percent of polyolefin wax, 5 to 15 weight percent of polypropylene, 10 to 50 weight percent of butene-propylene copolymer, 2 to 40 weight percent of DCPD (dicyclopentadiene) resin, and A hot melt composition for an electronic part or an electric part, comprising 0.1 to 5% by weight of polybutene. The hot melt composition for an electronic part or an electric part according to claim 1, wherein the polyolefin wax is a polypropylene wax or a polyethylene wax. The hot melt composition for an electronic part or an electric part according to claim 2, comprising 5 to 20% by weight of polypropylene wax and 5 to 20% by weight of polyethylene wax. The hot melt composition for an electronic part or an electric part according to claim 3, wherein the polypropylene wax has a molecular weight of 1000 to 5000, and the polyethylene wax has a molecular weight of 1000 to 3000. The hot melt composition for an electronic part or an electric part according to claim 1, wherein the butene-propylene copolymer has a molecular weight of 1000 to 50000. The hot melt composition for an electronic part or an electric part according to claim 1, wherein the DCPC resin has a molecular weight of 1000 to 50000. The hot melt composition of claim 1, further comprising at least one component selected from fillers, plasticizers, antioxidants, flame retardants and colorants.