KR20200137390A - Waterproof tape for mobile device - Google Patents

Abstract

The present invention relates to a waterproof tape for a mobile device composed of a foam layer having pores in a deep layer and a multi-layer adhesive layer formed of a silicone-based adhesive composition on both sides. When attached to an adherend selected from the group consisting of glasses, plastic substrates, and metal substrates, it has excellent adhesion to the adherend at low and high temperatures, and the adhesion of the curved substrates is improved, thereby having excellent water resistance, resilience resistance, and impact resistance.

Description

Waterproof tape for mobile devices {WATERPROOF TAPE FOR MOBILE DEVICE}

The present invention relates to a waterproof tape for a mobile device, and more particularly, a foam layer having pores in a deep layer and a multi-layer adhesive layer formed of a silicone-based adhesive composition on both sides to provide excellent adhesion to an adherend at low and high temperatures. The present invention relates to a waterproof tape for mobile devices that improves the adhesion of a curved substrate with excellent waterproofing, repelling resistance and impact resistance.

Conventionally, in various fields, an adhesive tape having an adhesive layer formed on a substrate has been used for various purposes such as bonding and fixing.

In addition, a method of using a foam as a base material and increasing the thickness of the adhesive layer is known as a part of increasing the adhesion to the adherend among conventional adhesive tapes.

However, recently, in electronic devices such as mobile phones, displays, and touch screen panels (TSPs), more and more devices having curved surfaces are increasing, and as weight reduction, miniaturization, and thickness reduction are achieved, the demand level for an adhesive tape is increasing. For example, it is required to be able to provide waterproof properties against pollutants such as moisture or water penetrating from the outside of electronic devices and absorb external shocks while being thin, and to enable repulsion resistance with high adhesion even in curved areas in various environments at low and high temperatures. Has become.

For example, Patent Document 1 discloses a waterproof tape having improved adhesion, and as a tape including a base layer and an adhesive layer having a filler layer on one side, the filler layer is an acrylic binder and a filler layer to increase impact resistance and adhesion of an adherend. It includes an impact resistant filler having a plurality of hollow fine particles, wherein the hollow fine particles contain liquefied hydrocarbon as a nucleating agent, and a coating film disposed on the outer surface of the liquefied hydrocarbon is characterized.

However, although the contribution of the intermediate filler layer is large for the purpose of imparting waterproofing and impact resistance, although the characteristics of the upper and lower adhesive layers attached to the substrate are also important, in the above invention, the physical properties of the adhesive layer were mentioned. none.

In addition, Patent Document 2 relates to a double-sided adhesive tape and a method of manufacturing the same, and is disposed on the base layer, the base layer, and formed from an acrylic binder containing a chemical resistant additive containing a diacrylate material, and Disclosed is a double-sided adhesive tape including a first adhesive layer and a second adhesive layer formed from a monomer mixture containing a plurality of acrylate compounds and acrylic acid, each disposed on the upper surface of the intermediate layer. In addition, it is characterized in that the first and second adhesive layers form a copolymer including an acrylate compound and acrylic acid, including a chemical resistant additive and pore particles that prevent the penetration of contaminants into the acrylic binder in the intermediate layer.

However, although the double-sided adhesive tape may have good impact resistance, it is difficult to expect in terms of improving waterproofness since the adhesive layer contains a hydrophilic material such as acrylic acid.

Patent Document 3 discloses a silicone foam cushion adhesive sheet in which a cushion layer having excellent cold and heat resistance is formed from -70°C to 200°C by using a silicone cushion layer in order to increase the shock absorption and durability than the urethane foam. However, in the adhesive layer, a method for increasing the adhesion to the adherend is not sufficient. Accordingly, the present inventors have been devised to solve the problems of the prior art, consisting of a foam layer having pores in a deep layer and an adhesive layer on both sides, but at least one of the two-sided adhesive layers is formed of a silicone-based adhesive composition. Thus, the present invention was completed by improving the adhesion of the curved substrate and confirming the waterproof property.

Republic of Korea Patent Registration No.1661501 (2016.10.04. Announcement) Korean Patent Registration No. 1658608 (announced on September 21, 2016) Korean Registered Patent No. 1187370 (announced on Oct. 02, 2012)

It is an object of the present invention to provide a waterproof tape for a mobile device having excellent adhesion to an adherend at low and high temperatures, and excellent waterproof, repulsion and impact resistance.

In order to achieve the above object, the present invention is composed of a foam layer having pores in the deep layer and a multi-layer adhesive layer formed of a silicone-based adhesive composition on both sides, and any one selected from the group consisting of glass, plastic substrates, and metal substrates. Provides a waterproof tape for mobile devices with excellent waterproof properties after 1 hour at 45℃ when attached to a single adherend.

The waterproof tape for a mobile device of the present invention is characterized by implementing physical properties by controlling the properties of the adhesive layer on both sides formed on the foam layer having pores in the depth in order to increase adhesion with the adherend.

Therefore, the waterproof tape for a mobile device of the present invention has a peeling of 5 mm or less in the repulsive force evaluation at 60°C, and peeling of 5 mm or less in the repulsive force evaluation at -20°C. It has excellent adhesion, and thus has excellent waterproof, repulsion and impact resistance characteristics.

In the present invention, any one layer of the double-sided adhesive layer is an addition curable silicone pressure sensitive adhesive resin comprising at least one MQ resin, at least one organosiloxane polymer having a vinyl functional group, at least one organohydrogen silicon compound, and a hydrosilylation catalyst It includes.

At this time, any one of the double-sided adhesive layers has a storage modulus of 1500KPa or less at -20°C, a storage modulus of 10KPa or more at 60°C, and the ratio of the storage modulus of -20°C and 60°C is the following formula It is to meet 1.

Equation 1

15 ≤ K ≤ 60

In the above, K is the ratio of storage modulus at -20°C/storage modulus at 60°C.

According to the waterproof tape for mobile devices of the present invention, it has excellent adhesion to the adherend at low and high temperatures, and the surface of the tape is hydrophobic to prevent water from entering the close gap, and thus waterproof, impact resistance and shock absorption. This is excellent.

1 is a schematic diagram showing a method for evaluating repulsion resistance of a waterproof tape for a mobile device of the present invention.

Hereinafter, the present invention will be described in detail.

The present invention consists of a foam layer having pores in the deep part and a multi-layer adhesive layer formed of a silicone-based adhesive composition on both sides, but when attached to any one of the adherends selected from the group consisting of glass, plastic substrates, and metal substrates Provides a waterproof tape for mobile devices with excellent waterproof properties after 1 hour at 45℃.

The waterproof tape for a mobile device of the present invention implements physical properties by controlling the properties of the adhesive layer on both sides formed on the foam layer having pores in the deep layer in order to increase adhesion to the adherend, and the deep layer is provided on one side of the substrate layer. It includes a foam layer having formed pores.

In the above, the base layer serves as a support layer for the waterproof tape, and may include a material having adhesion to the adhesive layer on both sides and the foam layer having pores. For example, it may include a plastic material such as polyester-based, polycarbonate-based, polyolefin-based, polyimide-based, such as polyethylene terephthalate (PET).

In addition, it is preferable that the thickness of the base layer is 10 μm to 75 μm. At this time, if the thickness is less than 10 μm, the adhesive layer cannot support the adhesive layer due to its mechanical properties, and when it exceeds 75 μm, the thickness of the foam layer excluding the base layer and the adhesive layer on both sides to satisfy the required thickness of the waterproof tape Because of the reduction, the desired waterproof and impact resistance cannot be met.

In the above, the foam layer having pores is composed of an acrylic binder and pores, and may be formed by applying to one surface of the substrate layer.

The specific composition of the acrylic binder is not particularly limited. For example, in the present invention, the acrylic binder may be a polymer of a monomer mixture including 80 parts by weight to 99.9 parts by weight of a (meth)acrylic acid ester monomer and 0.1 parts by weight to 20 parts by weight of a crosslinkable monomer.

The pores of the foam layer contain a plurality of dense fine particles. The fine particles have a liquid hydrocarbon having a hollow portion formed therein, and may be composed of, for example, a mixture of one or more of 2-methylbutane or 2-methylpropane. The surface of the fine particles is made of a thermoplastic material, for example, may be composed of acrylonitrile or (meth)acrylic acid ester-based copolymer. In addition, calcium carbonate is included on the surface of the plastic material to improve the scattering property of the liquid hydrocarbon and further improve the impact resistance of the fine particles.

Since the foam layer may include pores having a diameter of 20 μm to 80 μm, and if the pore diameter is less than 20 μm, the density of the foam layer increases, so that the elasticity increases rather than absorbing the shock, thereby giving an impact to the adherend. It may cause defects in the adherend, and if it exceeds 80 μm, the proportion of pores in the foam layer becomes too high, resulting in a decrease in thickness uniformity and non-uniform impact absorption for each location.

The thickness of the foam layer is preferably 5 μm to 100 μm, which may vary depending on the total thickness of the multilayer waterproof tape to be manufactured. At this time, if the thickness is less than 5 μm, a sufficient pore layer cannot be obtained, and if the thickness exceeds 100 μm, since the thickness of the adhesive layer on both sides is relatively insufficient, the adhesion with the adherend may decrease, resulting in poor interlayer peeling. .

1 is a schematic diagram showing a method for evaluating repulsion resistance of a waterproof tape for a mobile device of the present invention. When evaluating repulsion resistance, the final evaluation specimen 210 attached with a polycarbonate or metal plate as an adherend using the waterproof tape for a mobile device of the present invention can be evaluated by making a bend in a jig 220 having a shorter length than the final evaluation specimen. have. However, the repulsion resistance evaluation is not limited thereto, and the evaluation can be conducted by making lower or higher flexures by evaluating with specimens and jigs of various sizes.

Specifically, as a result of evaluating the repellency resistance of the final evaluation specimen 210 having a length of 200 mm at 60° C. and -20° C. using a jig 220 having a length of 180 mm, peeling of 5 mm or less occurs. At this time, if the repulsion resistance evaluation result is peeled off exceeding 5 mm, a gap is generated with the adherend, and moisture and contaminants may penetrate into the device, thereby causing a malfunction.

Therefore, the waterproof tape of the present invention has excellent waterproofing properties and impact resistance when attached to a curved surface of an electronic device, since peeling of 5 mm or less occurs in both the repulsion evaluation at 60°C and the repulsion evaluation at -20°C. From these results, the waterproof tape of the present invention is preferable as a waterproof tape for mobile devices.

In the waterproof tape for a mobile device of the present invention, at least one of the adhesive layers on both sides is formed from a silicone composition containing a silicone resin. The silicone composition comprises at least one MQ resin [A]; At least one organosiloxane polymer [B] having a vinyl functional group; At least one organohydrogen silicon compound [C]; And an addition curable silicone pressure sensitive adhesive (PSA) resin containing a hydrosilylation catalyst [D].

Component A comprises a resin having R ₃ SiO _1/2 (M units) and SiO _4/2 (Q units), wherein each R is a predetermined alkyl group, for example a methyl group. However, the present invention is not limited thereto, and other aliphatic groups having about 20 or less carbon atoms may be used instead of the methyl group. In this case, the molar ratio of M units: Q units may range from about 0.6:1 to 4:1. Component A may comprise up to 5% by weight of silanol functionality, with less than about 1% by weight alternatively being used.

The component B is an organosiloxane polymer terminal blocked with a vinyl functional group represented by the following formula (1). These components may also contain additional vinyl functionality. These two or more organosiloxane polymers may have different molecular weights to control viscosity and degree of curing after coating.

Formula 1

R ¹ R ² ViSiO(R ³ R ⁴ SiO) _n SiR ⁵ R ⁶ Vi

In the above, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are an alkyl group or a phenyl group having 1 to 6 carbon atoms, and may be the same or different. The alkyl group represented by R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ may be exemplified by methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopentyl and cyclohexyl. The n is an integer greater than or equal to 1, and when the molecular weight is 25,000 to 200,000, the folding and bending properties of the intermediate layer are good.

The component C is a compound represented by the following formula (2) and includes at least one crosslinked organohydrogensiloxane compound having an average of at least 2 Si-H bonds per molecule. Organohydrogensiloxane compounds suitable for use as component C may be linear, branched or cyclic molecules and any mixtures or combinations thereof.

Formula 2

-(R ⁷ HSiO) _n-

In the above, R ⁷ is an alkyl group or a phenyl group having 1 to 6 carbon atoms, and the alkyl group represented by R ⁷ may be exemplified by methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopentyl and cyclohexyl.

Component D may include any catalyst known to those of skill in the art to be useful in promoting the hydrosilylation reaction. Component D may be a platinum group metal containing catalyst. By definition, a platinum group metal refers to ruthenium, rhodium, palladium, osmium, iridium and platinum metals, as well as any mixtures or complexes thereof. The platinum group metal may include solid or hollow particles, a layer deposited on a carrier such as silica gel or powdered charcoal, an organometallic compound or complex. Some examples of the platinum group metal-containing catalyst include chloroplatinic acid in hexahydrate or anhydrous form, or a platinum group metal-containing catalyst obtained by reacting this chloroplatinic acid with an aliphatic unsaturated organosilicon compound. A preferred example of the component D is the Pt 4000 catalyst, which is a platinum complex of 1,3 diethenyl-1,1,2,2-tetramethyldisiloxane diluted with a vinyl end-blocked polymer with a platinum concentration of about 5200 ppm ( Dow Corning Corporation) is used.

The waterproof tape for a mobile device of the present invention controls the properties of the adhesive layer on both sides in order to increase the adhesion with the adherend, and any one of the adhesive layers on both sides has a storage modulus of 1500 KPa or less at -20°C, It is preferable that the storage modulus at 60° C. is 10 KPa or more.

In this case, when the storage modulus at -20°C exceeds 1500 KPa, the adhesive layer becomes hard, and cracks may occur or adhesion with the adherend may be deteriorated. In addition, if the storage modulus at 60° C. is less than 10 KPa, the adhesive layer becomes fluid and the adhesive strength decreases or the dimensions become unstable.

Therefore, the waterproof tape for a mobile device of the present invention has excellent adhesion and adhesion in the range of -20 ℃ to 60 ℃ waterproof and shock absorption.

One of the two-sided adhesive layers is designed to satisfy the storage modulus ratio (G) represented by the following equation 1.

Equation 1

15 ≤ K ≤ 60

In the above, K is the ratio of storage modulus at -20°C/storage modulus at 60°C.

In the above, if the storage modulus ratio (K) is less than 15, it means that the glass transition temperature is sufficiently low to have sufficiently soft properties even at low temperatures, and in this case, since the adhesive strength is low and it is difficult to have sufficient cohesive strength, the impact absorption property is low. On the other hand, when the storage modulus ratio (K) exceeds 30, it means that the storage modulus at -20°C is considerably higher than at 60°C, which means that the viscoelasticity of the adhesive layer changes sensitively to temperature. do. Accordingly, the adhesion with the adherend at low and high temperatures may be greatly reduced, resulting in poor impact resistance and waterproof properties.

In the above waterproof tape for a mobile device of the present invention, it is preferable that any one of the adhesive layers on both sides has a thickness of 50 μm to 150 μm. At this time, if the thickness is less than 50 μm, the adhesive strength to the adherend of various materials such as curved shape or plastic, metal, glass, etc. is low, and high adhesion cannot be realized. On the other hand, when the thickness exceeds 150 μm , It is uneconomical due to the increase in cost and time when manufacturing waterproof tape.

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

The present examples are for explaining the present invention more specifically, and the scope of the present invention is not limited to these examples.

<Example 1>

Step 1: Forming a deep layer with a porous foam layer

Curing agent based on 100 parts by weight of an acrylic binder (n-butyl acrylate 70% by weight, methyl methacrylate 5% by weight, isobornyl acrylate 10% by weight, 2-hydroxyethyl acrylate 10% by weight and acrylic acid 5% by weight) A composition was prepared by adding 1.0 parts by weight of MDI-based adduct (Methyl diphenyl diisocyanate adduct) and 2.0 parts by weight of fine particles (920DE, Akzonobel), and the composition was applied to a thickness of 50 µm PET film (Toray Advanced Materials). After coating so as to be 70 μm, it was dried and cured in an oven at 120° C. for 5 minutes to form a foam layer having pores on the substrate layer. Thereafter, a PET film (Toray Advanced Materials Co., Ltd.) having a thickness of 38 μm subjected to silicone release treatment as a release sheet was laminated on the surface of the foam layer.

Step 2: forming an adhesive layer

Weight average molecular weight of 2,000 to 20,000 g/mol, OH content of less than 5% solid MQ resin 40 g [Component A], weight average molecular weight of 50,000 to 600,000 g/mol, main polymer resin having a vinyl functional group content of less than 0.1% 51 g [ Component B], 8.5 g of an organohydrogen silicon compound having a Si-H content of 0.5 to 1.5% [Component C] was added with 60 g of toluene as a solvent, and stirred for about 2 hours to achieve sufficient mixing at room temperature. To the mixture, 0.5 g of a platinum complex of 1,3 diethenyl-1,1,2,2-tetramethyldisiloxane [Component D] was added, and a total of 100 g was adjusted to prepare a pressure-sensitive adhesive composition.

The pressure-sensitive adhesive composition was coated on a fluorine release-coated PET film having a thickness of 75 μm to a thickness of 90 μm, dried and cured in an oven at 150° C. for 6 minutes to complete the adhesive layer on both sides to prepare a waterproof tape.

<Example 2>

A waterproof tape was prepared in the same manner as in Example 1, except that the first adhesive layer and the second adhesive layer contained 30g of component A and 61g of component B in step 2 of Example 1.

<Example 3>

A waterproof tape was manufactured in the same manner as in Example 1, except that the first adhesive layer and the second adhesive layer contained 50g of component A and 41g of component B in step 2 of Example 1.

<Comparative Example 1>

The first adhesive layer was the adhesive layer of step 2 of Example 1, and the second adhesive layer was performed in the same manner as in Example 1, except that the acrylic binder of step 1 of Example 1 was used. Was prepared.

<Comparative Example 2>

The first adhesive layer and the second adhesive layer were carried out in the same manner as in Example 1, except that the acrylic binder of Step 1 of Example 1 was used and 1 part by weight of a trimethoxy-based silane coupling agent was included. Was prepared.

<Experimental Example> Evaluation of physical properties

The following physical properties were evaluated for the waterproof tapes prepared in Examples 1 to 3 and Comparative Examples 1 to 2, and the results are shown in Table 1 .

(1) Storage modulus (kPa)

Viscoelasticity was measured in shear mode (1 Hz) using ARES (TA instruments), which is a dynamic viscoelasticity measuring device (Frequency: 1 rad/sec). After removing the release film, the waterproof tapes of Examples and Comparative Examples were laminated to have a thickness of 1 mm, and the laminate was punched out with a puncher having a diameter of 8 mm and used as a specimen. It was measured at a temperature rise rate of 10°C/min in the temperature range of -50 to 100°C, and the elastic modulus at -20°C and 60°C was recorded.

(2) Adhesion (gf/in)

A sample of a PET film/multilayer adhesive layer/PET film structure was prepared, and the sample was cut into strips of 1 inch×15 cm. Attach the strip to stainless steel, and use an analyzer (Texture Analyzer, TAXplus/50, SMS) 60 minutes after attaching, using a 180 degree peel test at a speed of 5 mm/sec (0.3 m/min) ( peel test) method was used to measure the peel force.

(3) repulsion resistance

As shown in FIG. 1, a polycarbonate or metal plate is attached as an adherend to a waterproof tape specimen made on a 200 mm×20 mm acrylic plate to make a final evaluation specimen 210, and the evaluation specimen is a jig 220 having a width of 180 mm. After making the bend by putting in, the peeled distance was measured under the evaluation conditions (60°C, -20°C, 72 hours, respectively).

(4) Impact resistance evaluation

The prepared waterproof tape specimen is cut into a strip of 20 mm × 20 mm in size and 0.7 mm in width, and the cut specimen is attached between the glass and the adherend (polycarbonate or metal plate). The energy at which the waterproof tape breaks was measured while varying the weight heights of 50g and 100g vertically on the thus-made evaluation specimen in a DuPont tester.

(5) Water resistance evaluation

A specimen cut into a 0.7 mm strip was attached between the glass and the adherend (polycarbonate or metal plate). The resulting specimen for evaluation was left at room temperature for 24 hours, and then a shock of 100mJ was applied, and then it was put into a 1.5m water bath heated to 45°C. Then, after 1 hour, the waterproofness was confirmed.

○: There is no trace of moisture penetration into the interior.

×: There is a trace of moisture infiltrating into the interior.

As shown in Table 1, in the case of Examples 1 to 3, the ratio of the storage modulus at -20°C and the storage modulus at 60°C was not large, so the repulsion resistance at each temperature was excellent. It shows good results.

On the other hand, in the case of Comparative Example 1, a pressure-sensitive adhesive having a low storage modulus ratio was applied to one side and a pressure-sensitive adhesive having a high ratio on the other side. However, a large difference in properties between low and high temperatures occurred, so that good results were not obtained in terms of waterproofing.

In addition, in the case of Comparative Example 2, there was a large difference in physical properties between low and high temperatures, and sufficient physical properties were not satisfied with respect to waterproofness.

210: Specimen for evaluation of repellency (waterproof tape for mobile device of the present invention)
220: jig for evaluating repulsion resistance

Claims (5)

It consists of a foam layer having pores in the deep layer and a multi-layer adhesive layer formed of a silicone-based adhesive composition on both sides,
A waterproof tape for mobile devices with excellent waterproof properties after 1 hour at 45°C when attached to any one of the group consisting of glass, plastic and metal substrates. The waterproof tape for a mobile device according to claim 1, wherein peeling of 5 mm or less occurs when the waterproof tape is evaluated for repulsion at 60°C. The waterproof tape for a mobile device according to claim 1, wherein peeling of 5 mm or less occurs when the waterproof tape is evaluated for repulsion at -20°C. The method of claim 1, wherein the silicone-based adhesive composition comprises at least one MQ resin, at least one organosiloxane polymer having a vinyl functional group, at least one organohydrogen silicon compound, and an addition curable silicone pressure sensitive adhesive resin including a hydrosilylation catalyst. Waterproof tape for mobile devices, characterized in that to. According to claim 1, wherein the two-sided adhesive layer has a storage modulus of 1500 KPa or less at -20 °C, a storage modulus of 10 KPa or more at 60 °C, and the ratio of the storage modulus of -20 °C and 60 °C is the following formula Waterproof tape for mobile devices, characterized in that it meets 1:
Equation 1
15 ≤ K ≤ 60
In the above, K is the ratio of storage modulus at -20°C/storage modulus at 60°C.

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