KR102106994B1 - Adhesive composition for temperature insensitive pressure sensitive adhesive(psa) tape - Google Patents

Abstract

The present invention is a first rubber made of unvulcanized natural rubber (NR); A second rubber made of one or more synthetic rubbers; Adhesive resin; And to the adhesive composition comprising an anti-aging agent, the acrylic monomer is a grafted polymerized chloroprene rubber (CR) characterized in that the adhesive composition for a temperature-sensitive adhesive tape, characterized in that the temperature-sensitive adhesive tape according to the invention For the adhesive composition for a vinyl-based adhesive tape, chloroprene rubber modified simply by graft polymerization without significantly changing the composition of the existing adhesive used, and having the same or superior adhesive strength as the conventional vinyl-based adhesive tape A decrease in adhesive strength due to an increase in temperature in the surrounding environment can be improved to realize a temperature-insensitive adhesive tape without a telescopic phenomenon or sagging and detachment from a tape bonding site.

Description

Adhesive composition for temperature-sensitive adhesive tapes {ADHESIVE COMPOSITION FOR TEMPERATURE INSENSITIVE PRESSURE SENSITIVE ADHESIVE (PSA) TAPE}

The present invention relates to an adhesive composition for an adhesive tape, and more particularly, to an adhesive composition for an adhesive tape in which the degree of decrease in adhesive strength due to an increase in temperature is reduced.

Vinyl adhesive tapes that are currently used in Korea, especially 'PVC electrical insulating tapes', are usually coated with an adhesive dissolved in a solvent on a fabric film on the back side of the fabric, then heated to remove the solvent and wound around a cylindrical paper roll to vertically Cut into The adhesive used here is prepared by using styrene-butadiene rubber (SBR), which is a kind of natural rubber and synthetic rubber, as a main raw material, and appropriately mixing a tackifier, a small amount of antioxidant, and a stabilizer. The adhesive tapes manufactured using these are determined to be used only those that have passed the regulations according to the inspection method specified in KS CIEC 60454-2 "Electrical Adhesive Tapes", and most products pass the specifications set by KS.

However, despite passing all the KS standards, such as adhesive strength, tapes manufactured in Korea are sensitive to temperature changes compared to vinyl adhesive tapes imported directly from some countries or produced by OEM methods. When the tape is pushed away from the wound or stored in a hot place in the hot summer, the adhesive (resin) coated on the tape is easily retracted and pushed, and the bobbin comes out from the center and looks like a telescope tube. 'Telescope' phenomena, such as the subtracted shape, often occur during storage and are discarded as defective products before use.

In addition, even after use, in many cases, the tape is detached from the portion where the tape is wound in a hot temperature environment, such as in summer, and the purpose of the adhesive tape is often not achieved. The main reason for this problem is that the adhesive strength of the adhesive resin applied to the vinyl fabric is weakened with temperature rise, and accordingly, the inherent tension of the vinyl fabric cannot be overcome, so that the pushing occurs.

  In order to fundamentally solve the problems of low adhesion and telescope phenomenon described above, the fundamental method is insensitive to temperature change, and it is necessary to develop an adhesive material to maintain initial adhesion even when temperature rises or falls due to climate and seasonal changes.

Korean Patent Publication No. 10-2015-0118255 (Publication Date: 2014.04.11) Korean Patent Publication No. 10-2007-0076460 (Publication date: 2007.01.12)

The technical problem to be solved by the present invention is to develop an adhesive composition having a lower adhesive strength caused by a temperature change according to seasons and climate changes after manufacture or construction in a vinyl adhesive tape.

In order to solve the above technical problem, the present invention is a first rubber made of unvulcanized natural rubber (NR); A second rubber made of one or more synthetic rubbers; Adhesive resin; And it provides an adhesive composition for a temperature-sensitive adhesive tape, characterized in that chloroprene rubber (CR) in which an acrylic monomer is graft-polymerized is mixed in an adhesive composition comprising an anti-aging agent.

In addition, 10 to 25% by weight of the first rubber made of unvulcanized natural rubber (NR); 20 to 30% by weight of a second rubber made of one or more synthetic rubbers; Tackifying resin 30 to 60% by weight; And 0.5 to 2% by weight of an anti-aging agent, with respect to 100 parts by weight of the solids contained in the adhesive composition, the acrylic monomer is grafted polymerized chloroprene rubber (CR) 1 to 50 parts by weight, characterized in that the temperature-sensitive adhesive Provided is an adhesive composition for tape.

In addition, the second rubber, (i) styrene-butadiene rubber (SBR) or (ii) styrene-butadiene-styrene rubber (SBS), styrene-isoprene-styrene rubber (SIS) and ethylene-propylene-diene monomer rubber ( EPDM) provides a temperature-sensitive adhesive tape adhesive composition, characterized in that consisting of a mixture of at least one selected from the group consisting of styrene-butadiene rubber (SBR).

In addition, the tackifying resin is a mixture of (i) aliphatic (C5) petroleum resin-based tackifying resin or (ii) aliphatic (C5) petroleum resin-based tackifying resin and rosin ester-based tackifying resin, (iii) aliphatic (C5) petroleum Temperature desensitization characterized by a mixture of a resin-based tackifier resin and an alkylphenol-based tackifier resin, or (iv) a mixture of an aliphatic (C5) petroleum resin-based tackifier resin, a rosin ester-based tackifier resin and an alkylphenol-based tackifier resin. Provided is an adhesive composition for a type adhesive tape.

In addition, the acrylic monomer provides an adhesive composition for a temperature-sensitive adhesive tape, characterized in that it is an acrylic acid ester, methacrylic acid ester, or a mixture of acrylic acid ester and methacrylic acid ester.

In addition, the acrylic monomer provides a temperature-sensitive adhesive tape adhesive composition, characterized in that methyl methacrylate (MMA) and n-butyl acrylate (BA).

In addition, the graft ratio of the acrylic monomer is grafted polymerization chloroprene rubber provides an adhesive composition for a temperature-sensitive adhesive tape, characterized in that 5 to 50% of the chloroprene rubber.

The adhesive composition for a temperature-sensitive adhesive tape according to the present invention contains chloroprene rubber modified by graft polymerization simply without significantly changing the existing adhesive composition used in the vinyl-based adhesive tape. While having the same or superior adhesive strength as the tape, the decrease in the adhesive strength due to the temperature rise in the surrounding environment is improved, so that a temperature-insensitive adhesive tape without a telescopic phenomenon or sagging and detachment from the tape bonding site can be implemented.

1 is a reaction scheme of a graft polymerization reaction of methyl methacrylate (MMA) to chloroprene rubber.
2 is a differential scanning heat analysis (DSC) results of chloroprene rubber graft polymerized with methyl methacrylate.

In the description of the present invention, when it is determined that detailed descriptions of related known functions or configurations may unnecessarily obscure the subject matter of the present invention, detailed descriptions thereof will be omitted.

The embodiments according to the concept of the present invention may be modified in various ways and have various forms, and thus, specific embodiments will be illustrated in the drawings and described in detail in the present specification or application. However, this is not intended to limit the embodiment according to the concept of the present invention to a specific disclosure form, and it should be understood that it includes all modifications, equivalents, or substitutes included in the spirit and scope of the present invention.

The terms used in this specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “include” or “have” are intended to indicate that a feature, number, step, action, component, part, or combination thereof described is present, and one or more other features or numbers. It should be understood that it does not preclude the presence or addition possibilities of, steps, actions, components, parts or combinations thereof.

Hereinafter, the present invention will be described in detail.

The expression of adhesive force appears when the glass transition temperature of the polymer used with rubber is lower than the temperature of the environment in which the adhesive is used. That is, it is a temperature above a temperature exhibiting soft properties. When the ambient temperature rises, the property of repelling or viscoelasticity changes depending on the glass transition temperature of the components that exert adhesion, and the properties of flowing and sliding increase more than the property to be attached and fixed, resulting in a decrease in adhesion, resulting in telescopic phenomenon or tape dropping. In order to prevent this, it is basically appropriate to mix the components having a high glass transition temperature so that the change in viscoelasticity is small even at a temperature rise.

On the other hand, the adhesive component can exhibit the best adhesive strength when it has the same polarity as the adhesive. In the case of rubber-based adhesives, the adhesive strength depends on the surface properties of the base film or other plastics, as well as metals and ceramics with large polarity due to the molecular structure composed only of carbon and hydrogen. It may be degraded, but this surface property can be solved when a rubber component modified to have a molecular structure capable of properly controlling polarity is added.

In addition, adhesives are added to the pressure-sensitive adhesive to increase adhesion, and these are mainly used for low-molecular weight hydrocarbon-based petroleum resins and chemically modified rosin and alkylphenol small polymers. These adhesive resins have a higher softening point than rubber, but when mixed with rubber, the glass transition temperature is lowered instead of giving a strong adhesion. The tackifying resin must be essentially uniformly mixed with the adhesive base material such as the rubber to be mixed, but it should not be phase separated even if dissolved in a solvent by combining them.

Thus, the present invention has a high glass transition temperature and chloroprene having a proper polarity compared to natural rubber and styrene-butadiene rubber used in conventional vinyl adhesive tapes, in order to solve the compatibility, surface properties, and adhesion control to temperature as described above. As an adhesive composition for an adhesive tape comprising a rubber graft copolymer, the comonomer to be grafted is characterized in that the alkyl esters of various acrylic or methacrylic acids are monomers because the more easily the formation of radicals, the better the graft reaction. An adhesive composition for an adhesive tape is proposed.

To this end, the present invention comprises a first rubber made of unvulcanized natural rubber (NR); A second rubber made of one or more synthetic rubbers; Adhesive resin; And an adhesive composition comprising an anti-aging agent, wherein an acrylic monomer is grafted and polymerized with chloroprene rubber (CR) to provide an adhesive composition for a temperature-sensitive adhesive tape.

Preferably, the adhesive composition for temperature-sensitive adhesive tape according to the present invention comprises: 10 to 25% by weight of a first rubber made of unvulcanized natural rubber (NR); 20 to 30% by weight of a second rubber made of one or more synthetic rubbers; Tackifying resin 30 to 60% by weight; And it is characterized in that 1 to 50 parts by weight of chloroprene rubber (CR) polymerized with an acrylic monomer is mixed with respect to 100 parts by weight of the solid content included in the adhesive composition containing 0.5 to 2% by weight of an anti-aging agent.

At this time, the second rubber made of one or more synthetic rubbers is (i) styrene-butadiene rubber (SBR) or (ii) styrene-butadiene-styrene rubber (SBS), styrene-isoprene-styrene rubber (SIS ) And ethylene-propylene-diene monomer rubber (EPDM) is preferably made of a mixture of one or more selected from the group consisting of styrene-butadiene rubber (SBR).

The tackifying resin is used for viscosity control while improving adhesion and is rosin-based, terpene-based, and hydrocarbon. It may be a (hydrocarbon) -based material, for example, a hydrocarbon-based resin or a hydrogenated product thereof; Rosin resins or hydrogenated products thereof; Rosin ester resins or hydrogenated products thereof; Terpene resins or hydrogenated products thereof; Terpene phenol resins or hydrogenated products thereof; One or two or more mixtures selected from polymerized rosin resins, polymerized rosin ester resins, and the like can be used.

Preferably, the tackifying resin is a mixture of (i) aliphatic (C5) petroleum resin-based tackifying resin or (ii) aliphatic (C5) petroleum resin-based tackifying resin and rosin ester-based tackifying resin, (iii) aliphatic (C5). It is characterized by being a mixture of petroleum resin-based tackifying resin and alkylphenol-based tackifying resin, or (iv) aliphatic (C5) petroleum resin-based tackifying resin, rosin ester-based tackifying resin and alkylphenol-based tackifying resin.

At this time, the tackifying resin is composed of only an aliphatic (C5) petroleum resin-based tackifying resin, or an aliphatic (C5) petroleum resin-based tackifying resin, 50 to 90% by weight, rosin ester-based tackifying resin and / or alkylphenol-based adhesive It may be a mixture of imparting resin 10 to 50% by weight.

The acrylic monomer grafted to the chloroprene rubber (CR) is preferably an acrylic acid ester, methacrylic acid ester, or a mixture of acrylic acid esters and methacrylic acid esters for increasing compatibility with chloroprene rubber and changing surface properties. .

The acrylic acid or methacrylic acid ester may be obtained by ester reaction of acrylic acid or methacrylic acid with an alcohol having 1 to 12 carbon atoms.

Specific examples of the aforementioned acrylic monomers include methyl methacrylate, methyl acrylate, ethyl acrylate, n-butyl acrylate, ethyl hexyl acrylate, lauryl acrylate, 2-hydroxyethyl methacrylate, and the like.

Meanwhile, in the copolymer of chloroprene rubber-acrylic monomer, the acrylic monomer may be graft polymerized at a graft ratio of 5 to 50%.

Furthermore, the adhesive composition for temperature-sensitive adhesive tape according to the present invention is one selected from the group consisting of ultraviolet stabilizers, antioxidants, colorants, reinforcing agents, fillers, antifoaming agents, surfactants, and plasticizers in a range that does not affect the effects of the invention The above additives may be further included.

The adhesive composition for a temperature-sensitive adhesive tape according to the present invention can solve a decrease in adhesive strength due to a temperature rise by adjusting the type and graft ratio of the grafted monomer of the adhesive material to be mixed.

Hereinafter, the present invention will be described in more detail with reference to Examples.

The embodiments according to the present specification may be modified in various other forms, and the scope of the present specification is not interpreted to be limited to the embodiments described below. The embodiments of the present specification are provided to more fully describe the present specification to those skilled in the art.

<Example>

1. Manufacturing example

(1) Preparation of adhesive

The conventional adhesive for vinyl-based adhesive tape was prepared with the following composition. Natural rubber (STR-5L) and styrene-butadiene rubber (Kumho Petrochemical, SBR1502) lowered using a roll mill are dissolved in C6 petroleum solvent at room temperature, respectively, and C5 of Kolon Industries as an adhesive resin. 12, 28, 8% by weight of petroleum resin C-1100, A-1100, and T-3100, 4% by weight of alkylphenol-based adhesive resin, and 1% by weight of wing stay L as a rubber aging inhibitor. These solids were adjusted to be 30% by weight relative to the solvent. At this time, the viscosity is approximately 30,000 cps.

  Next, after measuring the weight of the dried graft polymer, it was dissolved in toluene or 2-butanone at 30% by weight and mixed with the composition used in the following examples in the existing coating adhesive to prepare the adhesive of the desired invention in various proportions. .

(2) graft polymerization

An example of the process of graft polymerization of methyl methacrylate or other acrylic monomers with an acrylic monomer on chloroprene rubber (A-90, A-400 from Denka) is as follows. After installing a mechanical stirrer and thermometer on a 1000 ml 4-neck resin kettle, add toluene or 2-butanone (MEK) solvent and completely dissolve the specified amount of chloroprene rubber. After the temperature was adjusted to 80 ° C, methyl methacrylate or an acrylic monomer was added at about 10-50 wt% of chloroprene rubber, and benzoyl peroxide (BPO), an initiator, was added at around 3 wt% of chloroprene rubber to react for 1 to 2 hours or more. Order. After the reaction time, the contents in the reactor were washed three times with methyl alcohol and then dried under reduced pressure at room temperature. 1 is a reaction formula when graft polymerization of methyl methacrylate on chloroprene rubber. The graft ratio was determined by the ratio of the weight gain of the graft polymer to the initial chloroprene rubber obtained.

Table 1 below (the graft ratio of MMA and BA according to the solvent and reaction time for cloprene rubber), peroxide peroxide of methyl methacrylate (MMA) and n-butylacrylate (BA) with toluene or 2-butanone as a solvent. When graft polymerization is performed using benzoyl as an initiator, it is a result of the graft rate according to the polymerization reaction time. When 2-butanone was used as a solvent rather than toluene, the grafting rate was high, so the difference was not very large, and the reaction time was more than 1 hour. And FIG. 2 shows a glass transition temperature ( T _g ) of -38.3 degrees Celsius, which is higher than that of the original chloroprene rubber of -42 degrees Celsius, as a result of differential scanning calorimetry (DSC) of chloroprene rubber graft polymerized with methyl methacrylate.

2. Examples and Comparative Examples

(1) Comparative Example 1

Comparative Example 1 is an example in which the existing adhesive used in the vinyl-based adhesive tape prepared with the above composition is used as it is.

(2) Comparative Example 2

In Comparative Example 2, an inorganic fine powder was also mixed with the pressure-sensitive adhesive used in Comparative Example 1 to increase temperature stability, and the average diameter of the amount corresponding to 10% by weight of the solid content of the pressure-sensitive adhesive used in Comparative Example 1 was about 1 micron. An adhesive prepared by mixing silica fine powder was used.

(3) Example 1

As in the Experimental Example, an adhesive material obtained by graft polymerization of methyl methacrylate on chloroprene rubber A90 manufactured by Denka Co., Ltd. was used as an adhesive prepared by mixing 5% by weight of the solid content of the adhesive.

(4) Example 2

As in the Experimental Example, an adhesive material obtained by graft polymerization of n-butyl acrylate on chloroprene rubber A90 manufactured by Denka Co., Ltd. was used as an adhesive prepared by mixing 5% by weight of the adhesive solid content of Comparative Example 1.

<Experimental Example> Measurement of the adhesive strength of the adhesive tape prepared in Examples and Comparative Examples

After coating the adhesive composition with a bar coater that can be applied to a PVC fabric film that produces an adhesive tape for electrical insulation with a certain thickness, dry the solvent for 1 minute in a forced circulation oven adjusted to a temperature of 100 to 120 ^o C, and then at room temperature. It was left for an hour. At this time, the thickness of the coated adhesive was carefully adjusted to be about 0.02 mm. This adhesive tape is cut to a size of 25 mm in width and 100 mm in length, and then compressed by a method of reciprocating once on a stainless steel plate (SUS 304) with a roller of 2 kg and left at room temperature for 10 minutes. 25 ℃, 50% RH conditions as a tensile rate at: 300mm / min 180 the test specimen made in the same way were the adhesion at room temperature to measure the force (g _f / 25mm) required to peel with a peel strength test Celsius 50 ^o After standing for 3 hours in an oven maintained at C, and then standing for 4 hours at room temperature again, the specimens were attached to the adherend in the same manner to prepare a test piece and evaluated. The measurement results are listed in Table 2 (Adhesive strength (peel strength) after standing at room temperature and high temperature and results of adherence of the adhesive) to the adhesive strength (g _f / 25mm) to the stainless steel plate.

×: No transition, △: Small shift, ○: Large shift

In Comparative Example 1, after the high temperature was left, the adhesive strength was lowered by 20% than the normal temperature and in the case of Comparative Example 2, the decrease was about 11%. However, in the case of Examples 1 and 2, there is no decrease in adhesive strength, or about 7%, which is much improved than Comparative Example 1, showing a successful effect of the present invention.

Claims (7)

A first rubber made of unvulcanized natural rubber (NR); A second rubber made of one or more synthetic rubbers; Adhesive resin; And to an adhesive composition comprising an anti-aging agent,
Acrylic acid ester, methacrylic acid ester, or a mixture of acrylic acid ester and methacrylic acid ester acrylic adhesive composition for temperature-sensitive adhesive tape, characterized in that a mixture of grafted polymer chloroprene rubber (CR). According to claim 1,
10 to 25% by weight of a first rubber made of unvulcanized natural rubber (NR);
20 to 30% by weight of a second rubber made of one or more synthetic rubbers;
Tackifying resin 30 to 60% by weight; And
With respect to 100 parts by weight of solids contained in the adhesive composition containing 0.5 to 2% by weight of an anti-aging agent,
Adhesive composition for a temperature-sensitive adhesive tape, characterized in that 1 to 50 parts by weight of chloroprene rubber (CR) in which the acrylic monomer is graft-polymerized is mixed. According to claim 1,
The second rubber,
selected from the group consisting of (i) styrene-butadiene rubber (SBR) or (ii) styrene-butadiene-styrene rubber (SBS), styrene-isoprene-styrene rubber (SIS) and ethylene-propylene-diene monomer rubber (EPDM) Adhesive composition for a temperature-sensitive adhesive tape, characterized by consisting of a mixture of one or more and styrene-butadiene rubber (SBR). According to claim 1,
The tackifying resin is a mixture of (i) aliphatic (C5) petroleum resin-based tackifying resin or (ii) aliphatic (C5) petroleum resin-based tackifying resin and rosin ester-based tackifying resin, (iii) aliphatic (C5) petroleum resin-based adhesive A mixture of imparting resin and alkylphenol-based tackifying resin, or (iv) a mixture of aliphatic (C5) petroleum resin-based tackifying resin, rosin ester-based tackifying resin and alkylphenol-based tackifying resin. Adhesive composition for tape. delete delete According to claim 1,
The acrylic monomer-grafted chloroprene rubber graft ratio of the chloroprene rubber is characterized in that 5 to 50% of the adhesive composition for temperature-sensitive adhesive tape.

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