JP3033490B2 - Tackifier for ethylene copolymer and adhesive composition thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a tackifier for an ethylene copolymer and an adhesive composition thereof.

[0002]

2. Description of the Related Art Conventionally, an ethylene copolymer is used as a base polymer, and a hydrocarbon resin such as an aliphatic petroleum resin, an aromatic petroleum resin, a terpene resin or a rosin resin is added as a tackifier thereto. Adhesive compositions are known, and generally, adhesive strength and holding power are required as adhesive performance. Further, when such an adhesive composition is used, for example, for cardboard packaging or bookbinding, it is usually subjected to hot-melt coating. It is also required that there be little change, that the initial color tone be nearly colorless and transparent, and that there be no odor. In addition, when the adhesive composition is used outdoors, light resistance is required.

In order to improve such heat stability, initial color tone and odor, a hydride of a hydrocarbon resin is usually used as a tackifier. In particular, hydrides of aromatic petroleum resins are widely used because of their good compatibility with the base polymer and excellent balance of adhesion performance. However, conventionally known aromatic hydrogenated resins have no problem in terms of initial color tone and odor, but have not been able to sufficiently satisfy requirements in terms of heating stability and light resistance. In addition, if a hydride of a so-called pure monomer resin is used, the heating stability can be improved in addition to the initial color tone and odor, but the production cost of the hydrogenated pure monomer resin cannot be satisfied.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a tackifier for an ethylene copolymer which is excellent in adhesive performance and excellent in initial color tone, odor, heat stability and light resistance, and an adhesive composition thereof. The purpose is to do.

[0005]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have conducted intensive studies on tackifiers used for ethylene-based copolymers. As a result, they have a high content of vinyltoluene as a polymerizable monomer. C9 with low content of
It has been found that the above object can be achieved by using a hydride of an aromatic hydrocarbon resin obtained by polymerizing a fraction. The present invention has been completed based on such new knowledge.

[0006]

DETAILED DESCRIPTION OF THE INVENTION That is, the present invention relates to a tackifier for an ethylene copolymer obtained by using a hydride of an aromatic hydrocarbon resin obtained by polymerizing a polymerizable monomer in a C9 fraction. And that the polymerizable monomer contains vinyl toluene in a proportion of 50% by weight or more and indene in a proportion of 20% by weight or less, and a hydrogenation rate of an aromatic ring of the aromatic hydrocarbon resin is 30% or more. Characteristic tackifier for ethylene copolymer, and adhesive composition containing 100 parts by weight of ethylene copolymer, 50 to 150 parts by weight of tackifier described above, and 10 to 100 parts by weight of wax About.

[0007] The tackifier for ethylene copolymer of the present invention is used for an ethylene copolymer obtained by using a hydride of an aromatic hydrocarbon resin obtained by polymerizing a polymerizable monomer in a C9 fraction. A tackifier, wherein the polymerizable monomer contains 50% by weight or more of vinyltoluene and 20% by weight or less of indene, and a hydrogenation rate of an aromatic ring of the aromatic hydrocarbon resin is 30% or more. Things.

The C9 fraction usually refers to one obtained by cracking naphtha. In the C9 fraction, styrene, vinyl toluene, α
-Other high-boiling compounds such as methylstyrene and indene. The conventionally known C9 fraction usually contains about 40% by weight of vinyl toluene and about 40% by weight of indene, respectively, and the remaining about 20% by weight is made of styrene or the like. In the present invention, the C9 fraction is distilled to remove indenes and high-boiling compounds in the C9 fraction, and the vinyl toluene content in the polymerizable monomer is 50% by weight or more, and the indene content is reduced. Is adjusted to be 20% by weight or less. The content of vinyltoluene is preferably at least 55% by weight, more preferably at least 60% by weight, and the more it is better. The content of indene is preferably at most 15% by weight, more preferably at most 10% by weight, and the better. When the content of vinyltoluene in the polymerizable monomer is less than 50% or the content of indene exceeds 20% by weight, the obtained hydrogenated hydrocarbon resin cannot satisfy the heat coloring property and the light resistance. In addition, the aromatic hydrocarbon resin is obtained by polymerizing such a polymerizable monomer by ordinary cationic polymerization. The resulting aromatic hydrocarbon resin has a softening point of 70 to 1
About 50 ° C. and the number average molecular weight are preferably about 300 to 2,000.

The aromatic hydrocarbon resin is hydrogenated so that the degree of hydrogenation of the aromatic ring becomes 30% or more. Preferably, the hydrogenation rate of the aromatic ring is 40 to 80%. When the hydrogenation rate of the aromatic nucleus is less than 30%, the heat coloring property and light resistance cannot be satisfied.

The hydrogenation reaction is carried out in the presence of a hydrogenation catalyst under conditions such that the hydrogenation rate of the aromatic hydrocarbon resin falls within the above range (the hydrogenation rate of the aromatic ring is 30% or more). It is adjusted appropriately.

As the hydrogenation catalyst, various catalysts such as metals such as nickel, palladium, platinum, cobalt, rhodium, ruthenium and molybdenum and metal compounds such as oxides and sulfides thereof can be used. Such a hydrogenation catalyst may be supported on a porous carrier having a large surface area, such as alumina, silica (diatomaceous earth), carbon, or titania. In the present invention, among these catalysts, it is preferable to use a nickel-diatomaceous earth catalyst from the viewpoint of easy adjustment of the hydrogenation rate within the above range and cost. The amount of catalyst used is
It is about 0.1 to 3% by weight, preferably 0.1 to 1% by weight of the aromatic hydrocarbon resin fat as the raw material resin. 0.1
If the amount is less than 3% by weight, the hydrogenation tends to be difficult to proceed.

The conditions of the hydrogenation reaction are such that the hydrogenation pressure is usually 3
The reaction temperature is usually in the range of about 0 to 300 Kg / cm ^2.
This is performed in a range of about 50 to 300 ° C. Preferably, the hydrogenation pressure is 100-200 Kg / cm ² and the reaction temperature is 2
00-290 ° C. Hydrogenation pressure is 30 kg / cm ²
If the reaction temperature is less than 150 ° C., the hydrogenation is difficult to proceed, and the hydrogenation pressure is 300 kg / cm.
If it exceeds ² , or if the reaction temperature exceeds 300 ° C., decomposition occurs and the softening point tends to decrease. The reaction time is generally about 1 to 7 hours, preferably 2 to 7 hours. The hydrogenation reaction is performed in a state where the aromatic hydrocarbon resin is melted or dissolved in a solvent. As the solvent,
Cyclohexane, n-hexane, n-heptane, decalin and the like can be used.

The use amount of the catalyst and the reaction time have been described in the case where a batch system is employed as the reaction mode. However, a flow system (fixed bed system, fluidized bed system, etc.) may be employed as the reaction system. it can.

The adhesive composition of the present invention comprises 100 parts by weight of an ethylene copolymer and 50 to 15 of the tackifier of the present invention.
0 parts by weight and 10 to 100 parts by weight of wax.

When the amount of the tackifier is less than 50 parts by weight, a sufficient adhesive force cannot be obtained, and when the amount exceeds 150 parts by weight, a sufficient holding force cannot be obtained, which is not preferable. Also,
When the amount of the wax is less than 10 parts by weight, the melt viscosity of the obtained adhesive composition is too high, and when the amount exceeds 100 parts by weight, a sufficient holding power cannot be obtained, which is not preferable.

The ethylene copolymer is a copolymer of ethylene and a monomer copolymerizable with ethylene, and may be any of those conventionally used in hot melt adhesives. Examples of the monomer copolymerizable with ethylene include vinyl acetate. The vinyl acetate content is usually 20
About 45% by weight. The molecular weight was determined to be 1 by the melt index (190 ° C., load 2160 g, 10 minutes).
It is preferably about 0 to 400 g / 10 minutes.

As the wax, those used in hot melt adhesives can be used. Specifically, petroleum waxes such as paraffin wax and microcrystalline wax, Fischer-Tropsch wax,
Synthetic waxes such as low molecular weight polyethylene waxes.

The adhesive composition of the present invention may further contain additives such as a filler and an antioxidant, if necessary.

[0019]

According to the present invention, it is possible to maintain a good balance of the initial color tone, odor and adhesive properties of a hydride of an aromatic hydrocarbon resin while maintaining excellent heat coloring properties and light resistance. The tackifier for a polymer can be provided at a low production cost. Further, by using the tackifier thus obtained, in addition to the above properties, it is possible to provide an adhesive composition having a small change in viscosity after heating. The adhesive composition of the present invention is hot-melt coated and can be used for applications such as cardboard packaging and bookbinding, and can also be used for various outdoor applications requiring light resistance.

[0020]

EXAMPLES The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. In each example, parts are based on weight.

Example 1 (1) Production of Tackifier A normal C9 fraction obtained by cracking naphtha (polymerizable monomer composition: vinyl toluene 37%, indene 35)
%, Other 28%) to obtain a purified C9 fraction (polymerizable monomer composition: vinyltoluene 58%, indene 9%, other 33%) having reduced high boiling components.
Polymerization was conducted by cationic polymerization to obtain a special C9-based hydrocarbon resin (softening point: 100 ° C., number average molecular weight: 700). 100 parts of the obtained special C9 hydrocarbon resin and nickel-diatomaceous earth catalyst ("N-113", manufactured by JGC Chemicals, Inc.)
2.0 parts are charged to an autoclave, and hydrogen pressure is 200 kg.
/ Cm ² , a reaction temperature of 270 ° C., and a reaction time of 5 hours. After completion of the reaction, the obtained resin was dissolved in 300 parts of cyclohexane, and the catalyst was removed by filtration. Thereafter, the filtrate and an antioxidant (“Irganox 1010”, manufactured by Nippon Ciba Geigy Co., Ltd.) are placed in a 1-liter separable flask equipped with a stirring blade, a reflux condenser, a thermometer, a temperature controller and a pressure indicator. ) Add 0.35 parts, 200 ° C, 20 torr
The solvent was removed by gradually raising the temperature and reducing the pressure until 790, the number average molecular weight was 790, the softening point was 102.5 ° C., and the hydrogenation rate of the aromatic ring was 94.
% Of hydrogenated C9-based hydrocarbon resin (tackifier) was obtained. Table 1 shows the physical properties of the obtained tackifier.

The hydrogenation rate was calculated from the H-spectral area of the aromatic ring appearing at about 7 ppm in 1H-NMR of the starting resin and the obtained hydrogenated resin based on the following equation. Hydrogenation rate = ｛1- (spectral area of hydrogenated resin /
Spectral area of raw material resin) x 100 (%). Also,
The softening point is based on the ring and ball method of JIS K 2531.

(2) Preparation of Adhesive Composition 40 parts of the adhesive agent obtained in (1) and wax (“Hi
-Mic-1080 ", manufactured by Nippon Seiro Co., Ltd.)
Melt mixed at 60 ° C. Thereafter, 40 parts of an ethylene-vinyl acetate copolymer ("Evaflex EV220", manufactured by Mitsui Dupont Chemical Co., Ltd.) was gradually added to prepare an adhesive composition.

Example 2 A tackifier was produced in the same manner as in Example 1 (1) except that the hydrogenation conditions were changed as shown in Table 1. Table 1 shows the physical properties of the obtained tackifier. Using this tackifier, an adhesive composition was prepared in the same manner as in Example 1, (2).

Comparative Example 1 In Example 1, (1), the usual C9 obtained by cracking naphtha was used instead of the special C9 hydrocarbon resin.
The fraction (polymerizable monomer composition: vinyl toluene 37%, indene 35%, other 28%) is directly polymerized by cationic polymerization to form a C9-based hydrocarbon resin (softening point 120
C., number average molecular weight 740), and a tackifier having an aromatic ring hydrogenation rate of 95% was produced in the same manner as in Example 1 (1) except that the hydrogenation conditions were changed as shown in Table 1. . Using the obtained tackifier, an adhesive composition was prepared in the same manner as in Example 1, (2).

Comparative Example 2 An adhesive having a hydrogenation rate of an aromatic ring of 70% was obtained in the same manner as in (1) of Comparative Example 1, except that the hydrogenation conditions were changed as shown in Table 1 in (1) of Comparative Example 1. An imparting agent was produced. Using the obtained tackifier, an adhesive composition was prepared in the same manner as in Example 1 , (2).

Comparative Example 3 Adhesion having a hydrogenation rate of aromatic ring of 5% was performed in the same manner as in Example 1 (1) except that the hydrogenation conditions were changed as shown in Table 1. An imparting agent was produced. Using the obtained tackifier, an adhesive composition was prepared in the same manner as in Example 1 , (2).

[0028]

[Table 1]

In the table, * 1 denotes a special C9 hydrocarbon resin (polymerizable monomer composition: vinyl toluene 58%, indene 9
%, Other 33%, softening point 100 ° C, number average molecular weight 70
0), and * 2 indicates a C9 hydrocarbon resin (polymerizable monomer composition: vinyl toluene 37%, indene 35%, other 28%, softening point 120 ° C, number average molecular weight 740).

The tackifiers or adhesive compositions obtained in the examples or comparative examples were evaluated by the following tests. The evaluation results are shown in Tables 2 and 3.

(Initial color tone) The tackifier was visually judged by Hazen Standard Color (H).

(Heat Colorability) 30 g of a tackifier was added to 70 c
c. Put in a mayonnaise bottle and leave it in a 180 ° C. circulating drier to visually determine the degree of coloring over time by Gardner Standard Color (G).

(Light resistance) After melting 10 g of a tackifier, put it in an ointment can having an inner diameter of 55 mm, allow it to cool, and irradiate it with light using a xenon lamp (“SUNEST”, manufactured by Heraeus) for 3 hours to give tackiness. The degree of coloring of the agent was visually determined according to the following criteria. ：: no coloring, Δ: slightly colored, ×: severely colored.

(Adhesive Strength) The adhesive composition heated and melted at 180 ° C. was hot-melt-coated on aluminum with a bar coater. This aluminum was adhered to a cardboard as an adherend with an adhesive area of 25 mm × 125 mm using an iron heated to 150 ° C., and then left at 20 ° C. for 24 hours. Then, at a temperature of 20 ° C., 18
A 0 degree peel test was performed, and the adhesive strength of cardboard (kg / 25
mm).

(Holding force) The adhesive composition heated and melted at 180 ° C. was hot melt-coated on aluminum with a bar coater. This aluminum was adhered to a cardboard as an adherend with an adhesive area of 25 mm × 25 mm using an iron heated to 150 ° C., and then left at 20 ° C. for 24 hours. afterwards,
The deviation (mm) between the aluminum and the cardboard when a load was applied under the conditions of 50 ° C., 0.5 kg and 1 hour was measured. The shorter the deviation, the better the holding power.

(Compound Heat Colorability) 50 g of the adhesive composition was placed in a 140 cc mayonnaise bottle, allowed to stand in a circulating air dryer at 180 ° C., and the degree of coloring after 48 hours was visually determined. ：: no coloring △: slightly colored ×: colored

(Compound Heat Viscosity Stability) The viscosity immediately after the preparation of the adhesive composition was measured at 150 ° C. using a HM-2 rotor with a B-type viscometer. Also, 50 g of the prepared adhesive composition was placed in a 140 cc mayonnaise bottle, and
Leave it in a 0 ° C circulating drier for 96 hours after heating,
It measured at 150 degreeC using the HM-2 rotor with the Brookfield viscometer.

[0038]

[Table 2]

[0039]

[Table 3]

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08F 240/00 C09J 123/04 C09J 157/02

Claims (2)

(57) [Claims] 1. A tackifier for an ethylene copolymer using a hydride of an aromatic hydrocarbon resin obtained by polymerizing a polymerizable monomer in a C9 fraction, wherein the polymerizable monomer is An ethylene copolymer containing 50% by weight or more of vinyl toluene and 20% by weight or less of indene, and having a hydrogenation rate of an aromatic ring of an aromatic hydrocarbon resin of 30% or more. Tackifier. 2. An adhesive composition comprising 100 parts by weight of an ethylene copolymer, 50 to 150 parts by weight of the tackifier according to claim 1, and 10 to 100 parts by weight of a wax.