JP3355671B2 - Composition for adhesives - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition for an adhesive and, more particularly, to a polymer mainly composed of a partially hydrogenated block copolymer in which a conjugated diene part is partially hydrogenated, and at least a dimer. The present invention relates to an adhesive composition having excellent workability, adhesive properties (tack, adhesive strength, holding power, etc.) and thermal stability by using a specific type of tackifier resin in a specific ratio.

[0002]

2. Description of the Related Art As applications of hot melt adhesives for sanitary materials, double-sided tapes for fixing napkins and tapes for disposable diapers are known as typical applications. In recent years, the application method of these hot-melt adhesives for sanitary materials is changing from the conventional bead method to the so-called nozzle method of applying a thread-like adhesive using a thin nozzle, with a lower melt viscosity, In addition, there has been a demand for a hot-melt adhesive having excellent adhesive properties with little change in quality due to long-term melt retention.

On the other hand, base polymers having various structures have been proposed for conventional hot melt adhesives for sanitary materials. For example, JP-B-44-17037 and JP-B-45-41518 disclose styrene-butadiene-
A hot-melt pressure-sensitive adhesive using a block copolymer of styrene or styrene-isoprene-styrene is disclosed. However, there is a problem that the block copolymer composed of styrene and butadiene is inferior in tackiness and is severely deteriorated by heating. On the other hand, block copolymers composed of styrene and isoprene have excellent tackiness, but if the adhesive composition is left at high temperatures for a long period of time, the molecular chains will break due to thermal degradation, and the viscosity and physical properties will change. There is a point.

In order to improve the thermal stability, a pressure-sensitive adhesive using a styrene-ethylene / butylene-styrene block copolymer obtained by hydrogenating a conjugated diene moiety has been proposed in Japanese Patent Publication No. Sho 55 (1993).
No. -7875. However, although the thermal stability is improved by hydrogenation, the adhesive strength is remarkably reduced, and the kind of the tackifier resin to be used is also limited.

Further, JP-A-2-1788 discloses a hydrogenated block copolymer in which a triblock structure and a specific block structure are combined. However, this combination also has an insufficient balance of melt viscosity, tackiness, and holding power, and particularly lacks tackiness. JP-A-1-20284 discloses an adhesive using a block copolymer having a specific hydrogenation rate. This pressure-sensitive adhesive composition has insufficient tack and melt viscosity.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a hot melt type adhesive having a low melt viscosity, an excellent balance of tackiness, tackiness and holding power, and excellent heat stability. It is to provide an adhesive.

[0007]

Accordingly, the present inventors have developed an excellent heat stability of a composition for an adhesive using a hydrogenated block copolymer, and an improved non-hydrogenated block copolymer. As a result of intensive studies on a composition for adhesives having excellent adhesive properties, which has a low melt viscosity, the total hydrogenation rate of the conjugated diene portion was found to be excellent. An adhesive composition using a mixture of 5 to 75% of a block copolymer and a specific ratio of a non-completely hydrogenated tackifier resin and a completely hydrogenated tackifier resin has a low melt viscosity,
The inventors have found that the balance of the characteristics of tackiness, adhesive strength, and holding power is excellent, and that they have good thermal stability, and have completed the present invention.

That is, the present invention comprises (1) a polymer block mainly composed of at least one vinyl aromatic hydrocarbon and a polymer block mainly composed of at least one conjugated diene compound. 5% to 75% or less partially hydrogenated block copolymer 100 parts by weight is hydrogenated diene moiety, (2) (a) of the non-full water添系b di <br/> down resins, terpene Resin, a tackifier resin containing one or two or more of a copolymer petroleum resin having 5 or 9 carbon atoms and an alicyclic petroleum resin, and (b) one or more completely hydrogenated resins. And the total amount of component (a) and component (b) is 50 to 400 parts by weight, and the compounding ratio of component (a) to component (b) is 5/95 to 80/20.
(% By weight), which is an adhesive composition comprising (1) and (2). Hereinafter, the present invention will be described in detail.

The partially hydrogenated block copolymer used in the present invention comprises at least one, preferably at least two, polymer blocks mainly composed of vinyl aromatic hydrocarbons and at least one conjugated diene compound. Polymer block.

The polymer block mainly composed of a vinyl aromatic hydrocarbon is a copolymer block of a vinyl aromatic hydrocarbon containing at least 50% by weight of a vinyl aromatic compound and a conjugated diene and / or a vinyl aromatic hydrocarbon. A homopolymer block is shown, and the polymer block mainly containing a conjugated diene is a copolymer block of a conjugated diene and a vinyl aromatic hydrocarbon containing a conjugated diene in an amount exceeding 50% by weight and / or a conjugated diene alone. 1 shows a polymer block. The vinyl aromatic hydrocarbons in the copolymer block may be distributed uniformly or in a tapered manner. A plurality of uniformly distributed portions and / or tapered distributed portions may coexist in each block.

The content of the vinyl aromatic hydrocarbon in the block copolymer is 20 to 45% by weight, preferably 25 to 4%.
0% by weight, and the content of vinyl aromatic hydrocarbons is 20%.
If the amount is less than 10% by weight, the holding power characteristics and the thermal stability are poor,
If it exceeds 45% by weight, the tackiness is poor.

The hydrogenation ratio of the entire aliphatic double bond based on the conjugated diene compound in the block copolymer is 5% or more and less than 75%, preferably 10 to 60%, more preferably 15 to 60%. It is a partially hydrogenated block copolymer satisfying up to 45%. When the hydrogenation rate of the entire aliphatic double bond based on the conjugated diene compound in the block copolymer is less than 5%, the thermal stability at high temperatures is poor, and when it is 75% or more, the tackiness is poor. Here, the hydrogenation rate of the entire aliphatic double bond based on the conjugated diene compound refers to the hydrogenated saturated hydrocarbon of all the aliphatic double bonds based on the conjugated diene compound incorporated in the block copolymer. Refers to the rate of conversion to binding. The hydrogenation rate can be obtained by a method using an infrared spectrophotometer or a nuclear magnetic resonance apparatus.

The method for producing the block copolymer before hydrogenation used in the present invention may be any known method,
For example, JP-B-36-19286, JP-B-43-1
No. 7979, JP-B-45-31951, JP-B-46-32415, JP-B-48-2423, JP-B-48-4106, and JP-B-49-369.
No. 57, Japanese Patent Publication No. 51-49567, Japanese Patent Publication No. 5
A method described in JP-A-6-28925 or the like is used. These are methods in which a polymerization initiator such as an organolithium compound is used in a hydrocarbon solvent to block polymerize a conjugated diene and a vinyl aromatic compound.

[0014]

Embedded image (In the above formula, A is a polymer segment mainly composed of a vinyl aromatic compound, and B is a polymer segment mainly composed of a conjugated diene. The boundary between the A segment and the B segment must always be clearly distinguished. There is no n
Is an integer of 1 or more. ) Or a general formula

[0015]

Embedded image (In the above formula, A and B are the same as described above, and X is an initiator such as a polyfunctional organolithium compound or silicon tetrachloride, tin tetrachloride, epoxidized soybean oil, polyhalogenated hydrocarbon, carboxylic acid ester, And a residue of a coupling agent such as a polyvinyl compound, wherein m and n are integers of 1 or more.)

The conjugated diene used in the present invention is a diolefin having a pair of conjugated double bonds.
-Butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene,
Examples thereof include 1,3-pentadiene and 1,3-hexadiene, and particularly common examples include 1,3-butadiene and isoprene. These may be used alone or in combination of two or more.

The vinyl aromatic hydrocarbon used in the present invention includes styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1,3-dimethylstyrene, α-methylstyrene, vinylnaphthalene, vinylanthracene Etc., and styrene is particularly common. These may be used alone or in combination of two or more.

The partially hydrogenated block copolymer used in the present invention has a number average molecular weight of 5,000 to 1,000,000.
0, preferably 10,000 to 800,000, more preferably 30,000 to 300,000, and the number average molecular weight of the block copolymer before hydrogenation is also preferably adjusted to this range.

Next, the above block copolymer is subjected to a hydrogenation reaction. As the catalyst used for the hydrogenation reaction,
(1) a supported heterogeneous catalyst in which a metal such as Ni, Pt, Pb, and Ru is supported on a carrier such as carbon, silica, alumina, and diatomaceous earth; and (2) an organic catalyst such as Ni, Co, Fe, and Cr. So-called Ziegler-type catalyst using an acid salt or acetylatone salt and a reducing agent such as organic Al, or Ru, R
Homogeneous catalysts such as so-called organic complex catalysts such as organometallic compounds such as h are known.

Specifically, Japanese Patent Publication No. 42-8704,
JP-B-43-6636 or JP-A-59-1
No. 33203, by the method described in JP-A-60-220147, hydrogenation in an inert solvent in the presence of a hydrogen catalyst to obtain a hydrogenated product, and a partially hydrogenated block used in the present invention A copolymer can be synthesized. At this time, the reaction temperature, reaction time, hydrogen supply amount, and catalyst amount are set so that the hydrogenation rate of the entire aliphatic double bond based on the conjugated diene compound of the block copolymer is hydrogenated within the range specified in the present invention. It is necessary to adjust etc.

The tackifier resin of the component (a) used in the present invention is a tackifier resin compatible with a styrene-butadiene system conventionally used as a tackifier resin in a hot melt adhesive or the like. Yes, for example, except for completely hydrogenated systems,
Rosin resin, terpene resin, partially hydrogenated terpene resin, aliphatic petroleum resin, copolymer petroleum resin having 5.9 carbon atoms, alicyclic petroleum resin, partially hydrogenated alicyclic petroleum resin, etc. Is mentioned.

The tackifier resin of the component (b) used in the present invention is a completely hydrogenated tackifier resin.
Examples thereof include a hydrogenated rosin resin, a hydrogenated terpene resin, and a hydrogenated alicyclic petroleum resin.

A feature of the present invention resides in that the tackifier resin of component (a) and the tackifier resin of component (b) are used in combination, and the total amount of component (a) and component (b) is It is used in an amount of 50 to 400 parts by weight, preferably 80 to 350 parts by weight, based on 100 parts by weight of the partially hydrogenated block copolymer of the component (1). When the total blending amount of the tackifier resin of the component (a) and the component (b) is out of this range, the adhesive properties of the adhesive tapes using the obtained adhesive composition are inferior, so that it is preferable. Absent. And component (a) and component (b)
Is used in the range of 5/95 to 80/20 (% by weight), preferably 5/95 to 60/40 (% by weight). When the composition for the adhesive agent obtained when the compounding ratio of the component (a) and the component (b) is out of this range, the tackiness,
It is not preferable because the holding power characteristics are poor.

Next, the stabilizer used in the present invention (component (3))
One to two or more stabilizers such as phenol stabilizers, phosphorus stabilizers, and sulfur stabilizers are used in an amount of 0.1 to 5 parts by weight, preferably based on 100 parts by weight of the partially hydrogenated block copolymer. Is used in the range of 0.2 to 4 parts by weight, more preferably 0.3 to 3 parts by weight. When the amount of the stabilizer is less than 0.1 part by weight, the effect of improving the thermal stability is not recognized. On the contrary, when the amount exceeds 5 parts by weight, the adhesive properties of the adhesive composition obtained are obtained. And the odor during heating for a long time is increased, which is not preferable.

In the present invention, a softener (component (4)) can be used if necessary. The softener of the component (4) is a petroleum-based softener, a paraffin-based softener, or the like. The softener of the component (4) generally comprises the partially hydrogenated block copolymer 10 of the component (1).
150 parts by weight or less based on 0 parts by weight, preferably 10 to 10 parts by weight
Used in the range of 150 parts by weight. If the amount exceeds 150 parts by weight, the use of the obtained composition for adhesives is not preferred in terms of adhesive properties, oil retention and odor.

[0026]

EXAMPLES Examples are shown below, but they do not limit the scope of the present invention.

Examples 1 to 3 and Comparative Examples 1 and 2 In a nitrogen gas atmosphere, n-butyllithium and tetramethylethylenediamine as a polar compound were added to a cyclohexane solution containing 15 parts by weight of styrene.
After polymerization at 1 ° C for 1 hour, a cyclohexane solution containing 70 parts by weight of butadiene was added, and polymerization was performed at 60 ° C for 2 hours. Thereafter, a cyclohexane solution containing 15 parts by weight of styrene was added, and polymerization was performed at 60 ° C. for 1 hour. The amount of n-butyllithium added depends on the melt flow of the finally obtained partially hydrogenated block copolymer (temperature: 200 ° C., load: 5 kg, JIS
K6870) was adjusted to about 10 g / 10 min.

Next, the block copolymer obtained above was hydrogenated with a Ti-based hydrogenation catalyst described in JP-A-59-133203, and the hydrogenation ratio of the entire butadiene portion was shown in Table 1. Phenolic stabilizer (Sumilyzer BH) per 100 parts by weight of partially hydrogenated block copolymer having
T, manufactured by Sumitomo Chemical Co., Ltd.) and 0.5 parts by weight of tris (nonylphenyl) phosphite. The hydrogenation rate was measured using a nuclear magnetic resonance apparatus.

Next, each partially hydrogenated block copolymer 100
150 parts by weight of a tackifier resin of component (a) (alicyclic petroleum resin, Alcon M100, manufactured by Arakawa Chemical) based on parts by weight, and a tackifier resin of component (b) (hydrogenated terpene resin, clearon) P-105, made by Yashara Chemical) 15
0 parts by weight and 100 parts by weight of a paraffin-based process oil (PW-90, manufactured by Idemitsu Kosan Co., Ltd.) were blended to prepare a hot melt adhesive composition. The thus-prepared adhesive composition was applied to a polyester film having a thickness of 50 μm to prepare a polyester adhesive tape. A polyethylene diaper press-molded to a thickness of 1 mm was used as an adherend, and the following performance evaluation was performed.

Melt Viscosity The composition for the adhesive was measured for melt viscosity at 180 ° C. using a Brookfield viscometer. Tackiness (Loop Tack) A loop-shaped sample having a length of 250 mm and a width of 15 mm was measured under the following conditions. (Adhesion area: 15 mm × 50 mm, adhesion time: 3 sec, adhesion and peeling speed: 500 mm / min) Adhesive force A sample having a width of 25 mm was attached to a polyethylene plate, and the 180 ° peel force was measured. (Peeling speed: 300 mm / min) Holding force A 1 kg load was applied to the bonded portion having an adhesive area of 25 mm × 25 mm, and the time required for the film to fall under a temperature atmosphere of 60 ° C. was measured. Heat stability The adhesive composition was left in a temperature atmosphere of 180 ° C. for 96 hours and examined for melt viscosity change, color change and odor. The composition for adhesives was indicated by ○, and the composition for adhesives having poor heat stability was indicated by ×. The results are shown in Table 1. Table 1
It can be seen that the composition for the pressure-sensitive adhesive according to the present invention exhibits a low melt viscosity and exhibits good tackiness, adhesive strength, creep resistance and thermal stability.

[0031]

[Table 1]

Examples 4 to 6 (AB) ₄ -X, AB, ABAA,
Styrene having ABAB and BAB structures /
Butadiene copolymer (molecular weight is about 10
g / 10 min. X used tin tetrachloride. ) Was polymerized and hydrogenated in the same manner as in Example 1 to prepare a composition for an adhesive agent in the same manner as in Example 1 except that the partially hydrogenated block copolymer was changed. Was evaluated. The results are shown in Table 2. From Table 2, the composition for adhesives using the partially hydrogenated block copolymer having the polymer structure specified in the present invention has a low melt viscosity, good tackiness, adhesive strength, creep resistance and thermal stability. It can be seen that

[0033]

[Table 2]

Examples 7 to 10 and Comparative Examples 3 to 6 The same procedure as in Example 2 was carried out except that the amounts of the tackifier resin and the softener were changed as shown in Table 3. A composition was prepared and its properties were evaluated. The results are shown in Table 3. From Table 3, it can be seen that the adhesive composition within the range specified in the present invention has a low melt viscosity, and has good tackiness, adhesive strength, creep resistance and thermal stability.

[0035]

[Table 3]

Examples 11 to 16 A composition for an adhesive was prepared in the same manner as in Example 2 except that the type of the tackifier resin was changed as shown in Table 4, and the properties thereof were evaluated. did. The results are shown in Table 4. From Table 4, it can be seen that the composition for an adhesive using the tackifier resin specified in the present invention has a low melt viscosity, and exhibits good tackiness, adhesive strength, creep resistance and thermal stability.

[0037]

[Table 4]

Examples 17 to 20 and Comparative Examples 7 to 9 Table 5 shows the types and amounts of stabilizers and the types and amounts of softeners.
The adhesive composition was prepared in the same manner as in Example 2 except that the composition was changed as shown in Table 2, and its properties were evaluated. Table 5 shows the results. From Table 5, the composition for the pressure-sensitive adhesive agent within the range of the kind and the amount of the stabilizer and tackifier resin specified in the present invention shows low melt viscosity, good tackiness, adhesive strength, creep resistance and heat. It turns out that it shows stability.

[0039]

[Table 5]

[0040]

The composition for adhesives of the present invention has low melt viscosity and excellent balance of each property of tackiness, adhesive strength and holding power and thermal stability.
It can be used for labels, pressure-sensitive thin plates, pressure-sensitive sheets, back glue for fixing carpets, etc., and is particularly effective as an adhesive for sanitary materials.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C09J 153/02 C09J 157/02 C09J 193/04

Claims (1)

(57) [Claims] 1. (1) Consisting of at least one polymer block mainly composed of a vinyl aromatic hydrocarbon and at least one polymer block mainly composed of a conjugated diene compound, wherein 5 is a conjugated diene moiety in the polymer. and% to 75% or less partially hydrogenated block copolymer 100 parts by weight is hydrogenated, (2) (a) incomplete water添系of rosin resins, terpene resins, number 5,9 carbon A component comprising: a tackifier resin containing one or more of a copolymerized petroleum resin and an alicyclic petroleum resin; and (b) a tackifier resin containing one or more of a completely hydrogenated resin. (1) the total amount of (a) and component (b) is 50 to 400 parts by weight, and the mixing ratio of component (a) and component (b) is 5/95 to 80/20 (% by weight); And (2) a composition for an adhesive.