KR20080093733A - Tackifier resin, preparation method of the same, and acrylic adhesive composition comprising the same - Google Patents

Abstract

A tackifier resin, a method for preparing the tackifier resin, and an acrylic adhesive composition containing the tackifier resin are provided to improve the compatibility with an acrylic polymer and to lower a softening point. A tackifier resin comprises 20-60 wt% of a cyclopentadiene-based monomer; 10-40 wt% of an acrylic monomer containing an ester group; and 20-60 wt% of a cyclic olefin-based monomer. The tackifier resin is prepared by polymerizing a cyclopentadiene-based monomer, an acrylic monomer containing an ester group and a cyclic olefin-based monomer to prepare a polymer; and hydrogenating the obtained polymer.

Description

Tackifier resin, preparation method thereof and acrylic pressure-sensitive adhesive composition comprising the same {Tackifier resin, preparation method of the same, and acrylic adhesive composition comprising the same}

The results of FIGS. 1 to 4 show the compatibility between the tackifier resin and the commercially available tackifier resin of the present invention and the acrylic polymer, and then mixed with each tackifier in the acrylic pressure sensitive adhesive composition, followed by solvent drying. After immersing one acrylic pressure-sensitive adhesive film in liquid nitrogen and rapidly cooling the film, the fracture surface was observed by scanning electron microscopy (SEM).

1 is a scanning electron microscope (SEM) photograph of an acrylic adhesive film specimen including a tackifying resin according to the present invention,

FIG. 2 is a scanning electron microscope (SEM) photograph of an acrylic pressure-sensitive adhesive film specimen not including a tackifier resin.

3 to 4 are scanning electron microscope (SEM) photographs of acrylic pressure-sensitive adhesive film specimens including other commercially available tackifier resins.

The present invention relates to a tackifying resin, a method for manufacturing the same, and an acrylic pressure-sensitive adhesive composition including the same, and an acrylic monomer containing a cyclopentadiene monomer and an ester group generated in the naphtha cracking process (hereinafter referred to as an "acrylate monomer"), It relates to a tackifying resin copolymerized with a cyclic olefin monomer and an acrylic pressure-sensitive adhesive composition comprising the same.

Dicyclopentadiene petroleum resin (hereinafter referred to as "DCPD petroleum resin") is generally produced by catalytic polymerization or thermal polymerization of dicyclopentadiene (hereinafter referred to as "DCPD") generated during naphtha cracking process. Hot Melt Adhesives (HMPSA) mainly comprising ethylene vinyl acetate (hereinafter referred to as "EVA") as base polymers, Hot Melt Pressure Sensitive Adhesives (HMPSA) using styrene block copolymers (hereinafter referred to as "SBCs") as base polymers, and natural rubber It is used for various uses, such as a tape (solvent type pressure-sensitive adhesive agent) which uses a base polymer as a base polymer. However, these DCPD-based petroleum resins were not compatible with acrylic adhesives due to their lack of compatibility with polymers having high polarity by containing ester groups such as acrylic polymers due to the molecular structure consisting of hydrogen and carbon.

In general, acrylic adhesives are colorless and transparent and have excellent seasonal resistance and oil resistance. However, acrylic adhesives have difficulty in selecting tackifier resins having excellent compatibility which is effective in improving adhesion performance such as 180 ^o peel strength, and in particular, low density polyethylene (hereinafter, " LDPE ", and the like, the adhesion to the substrate having low surface energy is poor, it is necessary to propose a method for overcoming this.

As a conventional technique for the pressure-sensitive adhesive resin for acrylic pressure-sensitive adhesive to overcome the physical properties of the acrylic pressure-sensitive adhesive, Japanese Patent Application Laid-Open No. 7-41749 et al. Hydrogenated a rosin ester obtained by esterifying a rosin with a polyhydric alcohol. The use of hydrogenated rosin esters (hereinafter referred to as " hydrogenation ") obtained by bleaching is shown.

The method has the advantage of improving the adhesive performance of the acrylic pressure-sensitive adhesive by the addition of rosin ester, but the limitation of the rosin which is a raw material taken from nature, the productivity limitation by the batch manufacturing process, and the heat-resistant cohesion when applied to the acrylic polymer There is a problem that degradation occurs.

Conventional techniques for producing acrylic point-and-adhesive resins using petroleum-based raw materials include US Pat. 2005/0182184 et al., Aromatic monomers such as styrene monomers, 2-ethylhexyl acrylate (2-EHA) and acrylic acid (Acrylic Acid). ), A polymerization method using a peroxide initiator is proposed.

However, when the resin is manufactured by this method, the weight average molecular weight is about 10,000 to polymerize and the compatibility with the acrylic polymer is weakened, so when applied to the acrylic adhesive, it is expected to expect a balanced adhesive performance in the initial adhesive strength or 180 ^o peel strength and cohesion strength. it's difficult.

Meanwhile, US Pat. No. 4,400,486, etc., as an acrylic adhesive resin, has a method of producing a resin by applying a hydrogenation reaction after thermally polymerizing a functional monomer such as aryl alcohol or a nonfunctional monomer such as vinyl acetate in DCPD. Is described.

The resin thus prepared shows excellent compatibility with the acrylic polymer and the 180 ^o peel strength of the general substrate is improved when the acrylic pressure sensitive adhesive is applied, but the molecular weight is too small and the introduction of an excessive polar group causes a decrease in the heat resistance cohesive strength of the pressure sensitive adhesive, especially LDPE. There is a problem in that the cohesive force decreases and a slight improvement in adhesion to low surface energy substrates such as such.

SUMMARY OF THE INVENTION An object of the present invention is to provide a tackifying resin, which is a modified DCPD-based petroleum resin having a softening point suitable for an acrylic adhesive composition while having excellent compatibility with an acrylic polymer when applied to an acrylic adhesive composition.

Another object of the present invention is to provide a method for preparing a tackifying resin, which is a DCPD petroleum resin modified to easily control a degree of polymerization while easily satisfying a high softening point suitable for application to an acrylic polymer.

Another object of the present invention is to provide an acrylic pressure-sensitive adhesive composition having a balance of initial adhesive strength, 180 ^° peel strength and cohesion, and particularly improved 180 ^° peel strength and heat resistance temperature for a substrate having low surface energy.

In one embodiment of the present invention provides a tackifying resin comprising 20 to 60% by weight of the cyclopentadiene monomer, 10 to 40% by weight of the ester group-containing acrylic monomer and 20 to 60% by weight of the cyclic olefin monomer in a repeating unit do.

In another embodiment of the present invention, hydrogenation of a polymer obtained from a monomer composition comprising 20 to 60% by weight of a cyclopentadiene monomer, 10 to 40% by weight of an ester group-containing acrylic monomer, and 20 to 60% by weight of a cyclic olefin monomer. The tackifying resin obtained by making it react is provided.

Tackifier resin according to an embodiment of the present invention may be a softening point of 80 ℃ or more.

In one embodiment of the present invention to obtain a polymer by polymerizing a monomer composition comprising 20 to 60% by weight of the cyclopentadiene monomer, 10 to 40% by weight of the ester group-containing acrylic monomer and 20 to 60% by weight of the cyclic olefin monomer ; And it provides a method for producing a tackifying resin comprising the step of hydrogenating the polymer in the presence of a catalyst.

In another embodiment of the present invention provides an acrylic pressure-sensitive adhesive composition comprising a tackifier resin according to the embodiment as the base resin and an acrylic polymer and a tackifier.

Another embodiment of the present invention provides an acrylic pressure-sensitive adhesive composition comprising a tackifier resin obtained in accordance with the above-described embodiment as an acrylic polymer and a tackifier as a base resin.

In the acrylic pressure-sensitive adhesive composition according to an embodiment of the present invention, the tackifier may include at least 10% by weight of the total composition.

The present invention will be described in more detail as follows.

The present invention intends to provide a tackifying resin which is improved by polymerizing DCPD and an acrylate monomer and then hydrotreating the insufficient compatibility of the conventional DCPD petroleum resin with the acrylic polymer.

However, it is difficult to apply the resin obtained by polymerizing DCPD and an acrylate-based monomer after the hydrotreating, since the tackifying resin is in a liquid state or has a low softening point of 80 ° C. or lower after the hydrotreating.

Accordingly, the present invention uses a cyclic olefin monomer together with a cyclopentadiene monomer and an acrylate monomer during polymerization.

Specifically, the tackifying resin according to the present invention may include 20 to 60% by weight of the cyclopentadiene monomer, 10 to 40% by weight of the acrylate monomer and 20 to 60% by weight of the cyclic olefin monomer in a repeating unit. have.

On the other hand, the tackifier according to the present invention may be prepared by polymerizing the polymer from a monomer composition comprising 20 to 60% by weight of cyclopentadiene monomer, 10 to 40% by weight of acrylate monomer and 20 to 60% by weight of cyclic olefin monomer. After obtaining it may be obtained by hydrogenation.

The cyclopentadiene-based monomer may be cyclopentadiene or derivatives thereof, in particular cyclopentadiene, alkyl substituted cyclopentadiene, dimers, trimers or codimers thereof. It is to be understood that cyclopentadiene and dicyclopentadiene are generally treated as approximately the same because cyclopentadiene is stably present as dicyclopentadiene, especially at ordinary temperature.

The ester group-containing acrylic monomer, that is, the acrylate monomer is not limited thereto. For example, methyl acrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, methyl methacrylate or butyl methacrylate. Can be mentioned. In particular, methyl acrylate may be advantageous in that the tackifier resin having a softening point of 80 ° C. or higher is easy to prepare.

In the present invention, the cyclic olefin monomer may serve as a comonomer and a polymerization regulator and / or a solvent. Examples thereof include cyclopentene, methyl cyclopentene, dihydro cyclopentadiene or dihydro cyclopentadiene derivative. Etc. can be mentioned.

When polymerized with cyclic olefins, polar-containing petroleum resins having a softening point of 80 ^° C. or more are easily produced. These results indicate that when cyclic olefin is used as a solvent, the degree of polymerization is controlled by solvent dilution, and a certain amount of cyclic olefin is reacted by radical or dials-elder during thermal polymerization. It is introduced into the resin to increase the ring structure density in the resin can be seen to effectively increase the softening point.

If a general solvent such as toluene, xylene or hexane, which is not a cyclic olefin monomer, is included in the polymerization process, a tackifying resin having an appropriate softening point may not be obtained, and a resin having a liquid or low softening point may be obtained.

In the content ratio of each monomer at the time of polymerization, that is, the ratio of the repeating units of the tackifying resin of the present invention, when the content of the cyclopentadiene-based monomer exceeds 60% by weight, the molecular weight of the polymerized resin becomes too large and the acrylic polymer and The problem of deterioration in compatibility may occur, and when the content is less than 20% by weight, the radical reaction may not be performed smoothly during thermal polymerization, and thus the resin conversion rate of the monomers may be lowered.

And, when the acrylate monomer content exceeds 40% by weight, the softening point of the polymerized resin is 70 It is difficult to obtain a polar-containing tackifier resin of the desired physical properties to be prepared below the ℃, when the acrylate monomer content is less than 10% by weight may cause a problem of deterioration of compatibility with the acrylic polymer.

On the other hand, when the content of the cyclic olefin-based monomer is more than 60% by weight may reduce the resin conversion of the monomers, when less than 20% by weight may be produced a high molecular weight resin may worsen the compatibility with the acrylic polymer.

Such a tackifying resin of the present invention may be advantageous in that the softening point of 80 ℃ or more, the softening point of 80 ℃ or more in terms of improving the adhesive strength and heat cohesive strength when applied to the acrylic pressure-sensitive adhesive composition as a tackifier. In addition, the obtained tackifier resin is excellent in compatibility with the acrylic polymer as the ester group is introduced into the molecular chain, which is advantageous in applying the tackifier in the acrylic adhesive composition.

The method for preparing a tackifying resin according to the present invention is obtained by polymerizing a cyclopentadiene monomer, an acrylate monomer and a cyclic olefin in the above-described content range for 2 to 6 hours at 250 to 300 ° C. The hydrogenated polymer can then be obtained by reacting in the presence of a hydrogenation catalyst. In the following examples, the Pd-based catalyst was used as the hydrogenation catalyst, but is not limited thereto. The conditions for the hydrogenation process may be appropriately controlled within the temperature range of 130 to 250 ^° C. and the pressure of 50 to 80 atmospheres.

The tackifier resin according to the present invention may be included as a tackifier in a general acrylic pressure-sensitive adhesive composition, in general, the acrylic pressure-sensitive adhesive composition includes an acrylate polymer as the base resin.

The acrylate polymer composition herein is not particularly limited, and when the tackifier resin according to the present invention is included as a tackifier, the cohesive force, 180 ^o peel strength, and initial adhesive strength are balanced compared to otherwise. It is possible to provide an acrylic adhesive having excellent adhesion to a substrate having a low surface energy such as LDPE.

In the case of including the tackifier resin according to the present invention in the acrylic pressure-sensitive adhesive composition may be effective in the content of 10% by weight or more, it may be advantageous in that less than 30% by weight of the low-temperature adhesive strength and the reduction of the heat-resistant cohesion strength is minimized. .

On the other hand, the acrylic pressure-sensitive adhesive composition may further include an additive within a range that does not violate the object of the present invention, examples thereof include antioxidants, stabilizers, crosslinking agents, reactive diluents, pigments, fillers, plasticizers and the like. .

In the following Examples to prepare a tackifying resin, and to apply it to the acrylic pressure-sensitive adhesive field to evaluate the performance, such as compatibility with the acrylic polymer, cohesion, peel strength, initial adhesive strength bar, the present invention by Example Of course, it is not limited.

<Production of Adhesively Bonded Resin>

Example 1

500 g of dicyclopentadiene, 200 g of methyl acrylate (Methyl Acrylate), and a cyclic olefin monomer were added dihydro dicyclopentadiene to a pressurized reactor and substituted with nitrogen, followed by polymerization at 280 ° C. for 1.5 hours. The polymerization solution was degassed under reduced pressure to remove the solvent and unreacted oil, and prepared by dissolving 1: 1 in a naphthenic solvent for hydrogenation.

The hydrogenation reaction was carried out in a continuous process using a hydrogenation reactor packed with a hydrogenation catalyst (Pd). Specifically, the polymer solution raw material prepared above was continuously introduced into the hydrogenation reactor using a high-pressure metering pump. The hydrogenation temperature was determined to be 230 ° C., the hydrogenation pressure was 80 atm, and the residence time of the raw material in the hydrogenation reactor was 1.5 hours. The reaction solution of which the hydrogenation reaction was completed was degassed under reduced pressure at 250 ° C. with a vacuum of 5 torr for about 10 minutes to prepare a final resin.

Example 2

A tackifying resin was prepared in the same manner as in Example 1, except that the polymerization time was changed to 2.5 hours.

Example 3

A tackifying resin was prepared in the same manner as in Example 1, except that cyclopentene was used instead of dihydro dicyclopentadiene as the cyclic olefin monomer.

Examples 4-6 and Comparative Examples 1-3

A tackifying resin was prepared in the same manner as in Example 1, except that the monomer composition was changed as in Table 1 below.

Comparative example  4

A tackifier was prepared in the same manner as in Example 1, except that xylene was used instead of the cyclic olefin monomer during polymerization.

Comparative Example 5

65% by weight of dicyclopentadiene and 35% by weight of acrylic acid were charged in a high pressure reactor and polymerized at 260 ° C. for 4 hours under a nitrogen atmosphere to prepare a polymer.

100 parts by weight of the obtained polymer, 100 parts by weight of cyclohexane and 3 parts by weight of 5% Pd-carbon were added to a high pressure reactor, and then gradually heated up to 150 ° C., whereby the pressure in the high pressure reactor was 50 kg / cm 2. Hydrotreated for 4 hours while maintaining. Cyclohexane was evaporated to obtain a tackified resin.

The physical properties of each of the resins obtained according to the Examples and Comparative Examples were measured, and the results are shown in Table 2 below.

The softening point was measured using an automatic softening point measuring instrument (Meitech, model name ASPT-S2), and the molecular weight (Mw) was analyzed using gel permeation chromatography (Hewlett-Packard Co., model name HP-1100 series). Oxygen content was analyzed using an elemental analyzer (Thermofinnigan, model name Flash 1112). Colors were observed using a Gardner standard color system.

Oxygen content is a value for estimating the content of acrylic monomers introduced into the tackifier resin molecular structure.Oxygen is not present in the DCPD and Oxygen is present in the acrylic monomer. The content of the acrylic monomers introduced into it can be estimated. In addition, since the compatibility with the acrylic binder may vary depending on the amount of the acrylic monomer introduced into the tackifier resin molecular structure, if the oxygen content is too low, the acrylic polymer in the tackifier resin structure means that the amount of acrylic monomer introduced is small. It can be assumed that the lack of compatibility with.

From the results in Table 2, it can be seen that the tackifying resins obtained according to the present invention are all softening points of 80 ° C. or more, and have an appropriate molecular weight and an acrylic monomer is properly introduced into the molecular structure.

<Preparation of Acrylic Adhesive Composition>

Examples 7-12

40% by weight of each resin obtained in Examples 1 to 6 was sufficiently dissolved in 42% by weight of toluene and 28% by weight of ethyl acetate to prepare a resin solution, and each resin solution was an acrylic adhesive (40% solids, manufactured by Burim Chemical Co., Ltd.). 20 wt%) was added to the same) to prepare an adhesive mixture.

The adhesive was applied to a release-treated tray at a thickness of 5 mm and then immersed in liquid nitrogen for rapid measurement after breaking for 24 hours at room temperature and 16 hours of solvent drying in a vacuum oven at 80 ° C. in a vacuum for cooling. SEM photographs of the fractured surfaces are shown in FIG. 1.

The adhesive was applied to a film (OPP) with a thickness of 40 μm, dried for 2 minutes in an oven at 120 ° C., and a solvent in the adhesive was removed to prepare a tape (sample). Loop Tack, 180 ^o peel strength, cohesion, and cohesive failure temperature of the tape (sample) prepared as described above are shown in Table 3 below.

Comparative Examples 6 to 10

An acrylic pressure-sensitive adhesive composition was prepared in the same manner as in Example 7, except that each resin obtained according to Comparative Examples 1 to 5 was added as a tackifier resin.

Loop Tack, 180 ^o Peel strength, cohesion, and cohesive failure temperature were measured.

Comparative Example 11

It is an acrylic adhesive (40% of solid content, the product of Bulim Chemical Co., Ltd.) composition without addition of a tackifier.

Loop Tack, 180 ^o Peel strength, cohesion, and cohesive failure temperature measurement results are shown in Table 4 below, and scanning electron microscope observation results are shown in FIG.

Comparative Example 12

A commercially available dicyclopentadiene petroleum resin tackifier (KOLON Emulsification Co., Ltd. SU-100) is added to an acrylic pressure sensitive adhesive (40% solids, manufactured by Burim Chemical Co., Ltd.) at a compounding ratio as shown in Table 4 below. The composition was prepared.

Loop Tack, 180 ^o Peel strength, cohesion, and cohesive failure temperature measurement results are shown in Table 4 below, and scanning electron microscope observation results are shown in FIG.

Comparative Example 13

Commercially available dicyclopentadiene-C9 petroleum resin tackifier (Kolon Oil Co., Ltd. SU-400) is added to an acrylic pressure-sensitive adhesive (40% solids, manufactured by Burim Chemical Co., Ltd.) at a compounding ratio as shown in Table 4 below. To prepare an adhesive composition.

Loop Tack, 180 ^o Peel strength, cohesion, and cohesive failure temperature measurement results are shown in Table 4 below, and scanning electron microscope observation results are shown in FIG.

The specific measuring method is as follows.

The Loop Tack was measured using the Loop Tack Tester (manufactured by Cheminstruments) according to the PSTC-16 standard (PSTC is a method of measuring pressure sensitive adhesives established by the US Pressure Sensitive Tape Council), and 180 ^o peel strength. Was measured according to the PSTC-1 standard using a universal testing machine (Instron), and the cohesive force was recorded at 25 ℃ according to the PSTC-7 standard using a Shear Tester (manufactured by Cheminstruments). The cohesive failure temperature was measured by using Shear Tester (Cheminstruments) to raise the weight of 1 kg weight at a rate of 2 ° C per 5 minutes by measuring the maximum temperature at which coagulation failure occurred.

From the results of Tables 3 to 4, it can be seen that the acrylic pressure-sensitive adhesive composition according to the present invention exhibits balanced performance in cohesion, 180 ° peel strength, and initial adhesion. In particular, it can be seen that the adhesion to the substrate having a low surface energy, such as LDPE.

In more detail, as in Comparative Examples 6 to 8, an acrylic pressure-sensitive adhesive composition including a tackifier obtained when the monomer composition of dicyclopentadiene, methyl acrylate, and cyclic olefin monomer is satisfied but is out of the content range. It can be seen that there is no effect of improving the physical properties at Loop Tack, 180 ° peel strength and cohesive failure temperature.

In addition, it can be seen that the acrylic pressure-sensitive adhesive composition (Comparative Example 9) including a tackifier composed of dicyclopentadiene, methyl acrylate, and xylene has a slight improvement in 180 ° peel strength and cohesive failure temperature.

In addition, the acrylic pressure-sensitive adhesive composition (Comparative Example 10) including a tackifier obtained by hydrogenating a polymer made of dicyclopentadiene and an acrylic acid monomer (Comparative Example 10) is particularly inferior in initial adhesive strength, loop tack and 180 ° peel strength, and in particular, adhesion to LDPE substrate. It can be seen that this falls.

In the case of not including the tackifier (Comparative Example 11), it can be seen that all of them are inferior in overall performance.

In the case of including a conventional dicyclopentadiene-based tackifier, it can be seen that since the compatibility with the acrylic polymer is inferior, the adhesion to the substrate is also inferior (Comparative Examples 12 to 13).

In addition, according to the results of FIGS. 1 to 4, when the tackifier is not added (see FIG. 2), and the acrylic pressure-sensitive adhesive composition including the tackifier of the present invention has excellent compatibility with the acrylic polymer film After formation, the fracture surface was observed to be smooth (see FIG. 1), whereas those containing dicyclopentadiene-based petroleum resin tackifiers which were not commonly used in acrylic adhesive compositions (FIGS. It can be seen that the nonuniformity is shown.

According to the present invention described in detail above, it is possible to obtain a tackifier resin having a softening point of 80 ° C. or higher while having excellent compatibility with an acrylic polymer. have.

In addition, the present invention can provide an acrylic pressure-sensitive adhesive composition with improved initial adhesion, 180 ° peeling strength and cohesion, and in particular, improves adhesion and heat resistance temperature to a substrate having low surface energy. It is useful as an adhesive or an adhesive.

Claims (7)

A tackifying resin comprising 20 to 60% by weight of a cyclopentadiene monomer, 10 to 40% by weight of an ester group-containing acrylic monomer, and 20 to 60% by weight of a cyclic olefin monomer in a repeating unit. A tackifying resin obtained by hydrogenating a polymer obtained from a monomer composition comprising 20 to 60 wt% of a cyclopentadiene monomer, 10 to 40 wt% of an ester group-containing acrylic monomer, and 20 to 60 wt% of a cyclic olefin monomer. The tackifying resin according to claim 1 or 2, wherein the softening point is 80 ° C or higher. Obtaining a polymer by polymerizing a monomer composition comprising 20 to 60 wt% of a cyclopentadiene monomer, 10 to 40 wt% of an ester group-containing acrylic monomer, and 20 to 60 wt% of a cyclic olefin monomer; And A process for producing a tackifying resin comprising the step of hydrogenating a polymer in the presence of a catalyst. An acrylic pressure-sensitive adhesive composition comprising an acrylic polymer as a base resin and a tackifying resin according to claim 1 or 2 as a tackifier. An acrylic pressure sensitive adhesive composition comprising an acrylic polymer as a base resin and a tackifier resin obtained according to the method of claim 4 as a tackifier. The acrylic pressure sensitive adhesive composition according to claim 5 or 6, wherein the pressure sensitive adhesive comprises at least 10% by weight of the total composition.

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