JP2003096422A - Adhesive composition and adhesive article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive article that is produced by forming the adhesive layer made of a hot melt adhesive including a hydrogenated block copolymer as a base polymer on the backing material and has increased adhesion properties. SOLUTION: The adhesive composition comprises (a) 100 mass parts of a hydrogenated block copolymer including the polymer block (A) of aromatic vinyl monomers and the polymer block (B) of conjugated diene monomer where >=70% of the carbon-carbon double bonds from the conjugated diene is hydrogenated, the content of the polymer block A is 3-70 mass % and the number- average molecular weight of 50,000 to 150,000, (b) 10-150 mass parts of polyethylene and (c) 50-300 pts.wt. of a tackifier resin. The adhesive composition is extruded on the backing material to give the adhesive article.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pressure-sensitive adhesive composition that can be extruded and a pressure-sensitive adhesive article having excellent pressure-sensitive adhesive performance.

[0002]

2. Description of the Related Art In recent years, adhesive articles such as adhesive tapes and sheets have come to be used in a wide range of industrial fields including industrial applications such as electricity, automobiles and construction, and various medical applications. ing. In addition, such an adhesive article is rapidly being used in household products such as dust removing rolls, sheets and mats.

Such an adhesive article is usually composed of a base material and an adhesive layer formed on the base material. For the formation of the adhesive layer, a liquid curable adhesive agent and a solvent type adhesive agent are used. Various pressure-sensitive adhesives such as adhesives, water-based pressure-sensitive adhesives, and hot-melt pressure-sensitive adhesives are used.

[0004]

However, when a liquid curable pressure-sensitive adhesive is used for forming the pressure-sensitive adhesive layer of a pressure-sensitive adhesive article, there is a problem that the pressure-sensitive adhesive layer obtained has insufficient pressure-sensitive adhesive performance.

On the other hand, when a solvent-type pressure-sensitive adhesive is used for forming the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer obtained has sufficient pressure-sensitive adhesive performance, but since the solution-type pressure-sensitive adhesive uses an organic solvent, There are problems that the working environment and the sanitary environment are deteriorated in the step of forming the adhesive layer, that the environment such as air pollution is required to be taken into consideration, and that the cost for solvent recovery is high.

Further, when the water-based pressure-sensitive adhesive is used, the influence on the environment is small as compared with the case where the solvent-type pressure-sensitive adhesive is used, but it takes time and energy to dry the formed pressure-sensitive adhesive layer. Therefore, there is a problem that the workability in the step of forming the adhesive layer is poor.

On the other hand, the hot melt type adhesive is
Since it is a type of adhesive that does not use solvents, it is non-polluting,
It has the advantages of high safety, no need for a solvent recovery step, and excellent energy saving and workability.

Here, as the hot-melt type pressure-sensitive adhesive, for example, one using a hydrogenated product of a block copolymer having a polymer block made of an aromatic vinyl monomer and a polymer block made of a conjugated diene monomer as a base polymer. It is known that when forming an adhesive layer from such a hot melt type adhesive, the base polymer is limited to a relatively small molecular weight such as a number average molecular weight of about 50,000 or less due to the solution viscosity. The resulting adhesive article is not satisfactory in adhesive performance represented by tackiness, and uses a solvent-free type adhesive such as a hot-melt type adhesive, and It has been desired to provide an adhesive article having excellent performance.

Therefore, an object of the present invention is to provide a hot-melt type pressure-sensitive adhesive containing a hydrogenated product of a block copolymer having a polymer block made of an aromatic vinyl monomer and a polymer block made of a conjugated diene monomer as a base polymer. An object of the present invention is to provide a pressure-sensitive adhesive article having a pressure-sensitive adhesive layer formed on a substrate, the pressure-sensitive adhesive article having improved adhesive performance.

[0010]

DISCLOSURE OF THE INVENTION The present inventors have made a hot melt using a hydrogenated product of a block copolymer having a polymer block made of an aromatic vinyl monomer and a polymer block made of a conjugated diene monomer as a base polymer. As a result of diligent studies on the improvement of the adhesive performance of an adhesive article in which an adhesive layer made of a type adhesive is formed on a substrate, polyethylene and a tackifying resin are applied to a relatively high molecular weight block copolymer having a specific structure. The pressure-sensitive adhesive composition containing a specific amount of can form an adhesive layer on the substrate by extrusion molding, the adhesive article obtained by this, found that the adhesive performance is significantly improved, the present invention completed.

That is, the present invention comprises (a) two or more polymer blocks A composed of an aromatic vinyl monomer, a conjugated diene monomer, and 70% of carbon-carbon double bonds based on the conjugated diene monomer. The above has one or more hydrogenated polymer block B, the content of the polymer block A is in the range of 3 mass% or more and 70 mass% or less, and the number average molecular weight is 50,000 or more and 150,000 or more. 150 parts by mass or more and 150 parts by mass of polyethylene (b) per 100 parts by mass of the hydrogenated block copolymer within the following range:
3 parts by mass or less, and (c) 50 parts by mass or more of tackifying resin 3
A pressure-sensitive adhesive article comprising a pressure-sensitive adhesive composition containing 100 parts by mass or less and a pressure-sensitive adhesive layer formed by extrusion of the pressure-sensitive adhesive composition on a substrate.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below.

The adhesive layer in the adhesive article of the present invention is
(A) Polymer block A composed of an aromatic vinyl monomer
2 or more and a conjugated diene monomer, and 70 carbon-carbon double bonds based on the conjugated diene monomer.
% Or more has one or more hydrogenated polymer blocks B, the content of the polymer block A is in the range of 3 mass% or more and 70 mass% or less, and the number average molecular weight is 50,000 or more and 150, 100 parts by weight of a hydrogenated block copolymer (hereinafter abbreviated as hydrogenated block copolymer (a)) in the range of 000 or less, (b) polyethylene 1
It is formed by extrusion-molding a pressure-sensitive adhesive composition containing 0 part by mass or more and 150 parts by mass or less and (c) 50 parts by mass or more and 300 parts by mass or less of a tackifying resin on a substrate.

First, the hydrogenated block copolymer (a) which constitutes the base polymer of the pressure-sensitive adhesive composition will be described.

Examples of the aromatic vinyl monomer constituting the polymer block A include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene and 2,4-dimethylstyrene (o, p). -Dimethylstyrene), vinylnaphthalene, vinylanthracene, etc., among which styrene or α-methylstyrene is preferably used. The polymer block A can be formed of one kind or two or more kinds of these aromatic vinyl monomers.

Examples of the conjugated diene monomer which constitutes the polymer block B include 1,3-butadiene (butadiene), isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene and 1,3. -Hexadiene and the like can be mentioned, and among these, isoprene, butadiene or a mixture thereof is preferable. The polymer block B can be formed of one kind or two or more kinds of these conjugated diene monomers.

The polymer block B in the hydrogenated block copolymer (a) is a carbon derived from the conjugated diene.
It is necessary that 70% or more of the carbon double bonds be hydrogenated, preferably 80% or more are hydrogenated, and particularly preferably 95% or more are hydrogenated.

By selecting the hydrogenated block copolymer (a) having a hydrogenation rate of 70% or more, deterioration of the base polymer during extrusion molding is suppressed and heat resistance of the obtained adhesive article is improved. It is possible to obtain an adhesive article that gives desired adhesive performance.

The hydrogenation rate of the carbon-carbon double bond derived from the conjugated diene in the polymer block B in the hydrogenated block copolymer (a) can be determined, for example, by measuring iodine value, infrared spectrophotometer or nuclear magnetism. It can be determined by a resonance device or the like.

The content of the polymer block A (content of the aromatic vinyl monomer) in the hydrogenated block copolymer (a) is in the range of 3% by mass or more and 70% by mass or less,
It is more preferable that the content is 10% by mass or more and 65% by mass or less. When the content of the polymer block A is less than 3% by mass, the cohesive force of the pressure-sensitive adhesive composition containing the hydrogenated block copolymer as a base polymer is poor and the extrusion moldability is lowered to form a good pressure-sensitive adhesive layer. Difficult to form. On the other hand, when the content of the polymer block A exceeds 70% by mass, the adhesive performance of the obtained adhesive layer becomes insufficient.

The number average molecular weight of the hydrogenated block copolymer (a) is in the range of 50,000 or more and 150,000 or less. When the number average molecular weight is less than 50,000, it becomes difficult to obtain an adhesive article having sufficient adhesive performance. On the other hand, when the number average molecular weight exceeds 150,000, the melt viscosity of the pressure-sensitive adhesive composition becomes high and extrusion molding becomes difficult even if the blending amount of polyethylene or tackifying resin is adjusted. Preferred number average molecular weight is 50,0
It is within the range of 00 or more and 100,000 or less.

In the hydrogenated block copolymer (a) used in the present invention, two or more polymer blocks A and one or more polymer blocks B are combined to form a block copolymer. However, the binding mode of the polymer block A and the polymer block B is not limited, and may be linear, branched, or any combination thereof.

The hydrogenated block copolymer (a)
Has a carboxyl group, a hydroxyl group, an acid anhydride group, an amino group, an epoxy group, a functional group such as a halogen atom or a substituent on a side chain including a main chain or a terminal within a range not impairing the gist of the present invention. May be.

The method for obtaining the hydrogenated block copolymer (a) is not particularly limited. For example, aromatic vinyl monomer and conjugated diene monomer are sequentially polymerized in an inert organic solvent such as hexane and cyclohexane using an alkyllithium compound as an initiator, and then the obtained block copolymer is hydrogenated by a known method. It is obtained by doing. Further, the hydrogenated block copolymer (a) can be obtained from a commercial product. Further, the hydrogenated block copolymer (a) may be used alone, or
You may use it in mixture of 2 or more types.

Next, the polyethylene (b) constituting the pressure-sensitive adhesive composition will be described.

The polyethylene (b) includes, for example, low density polyethylene, high density polyethylene, linear low density polyethylene and the like, and the kind and manufacturing method thereof are not particularly limited, and they may be used alone or in two kinds. You may mix and use the above. Among these, low density polyethylene obtained by the high pressure method is preferable because it gives good extrusion moldability.

Polyethylene (b) is JIS K 67
According to 60, it is possible to stably produce an adhesive article by using an MFR (melt flow rate) value of 0.5 to 15 (g / 10 minutes) at 190 ° C. and 2.16 kgf. From the viewpoint, it is preferable.

The blending amount of polyethylene (b) is 10 times that of hydrogenated block copolymer (a) as a base polymer.
It is in the range of 10 parts by mass to 150 parts by mass with respect to 0 parts by mass, and more preferably in the range of 30 parts by mass to 100 parts by mass. When the blending amount of polyethylene (b) is less than 10 parts by mass with respect to 100 parts by mass of hydrogenated block copolymer (a), the extrudability of the obtained pressure-sensitive adhesive composition becomes insufficient, while When it exceeds 150 parts by mass, the extrusion moldability is good, but the effect of improving the adhesive performance of the obtained adhesive layer is insufficient.

Next, the tackifying resin (c) constituting the pressure-sensitive adhesive composition will be described.

Examples of the tackifying resin (c) include generally known tackifying resins such as rosin-based resins, terpene-based resins, petroleum resins and styrene-based resins. The above may be used alone or in combination of two or more.

The compounding amount of the tackifying resin (c) is 10 times that of the hydrogenated block copolymer (a) as the base polymer.
It is in the range of 50 parts by mass to 300 parts by mass with respect to 0 parts by mass, and more preferably in the range of 100 parts by mass to 250 parts by mass. By setting the compounding amount of the tackifying resin (c) within this range, the effect of improving the adhesive performance of the obtained adhesive layer can be sufficiently exhibited, and the compounding amount of the tackifying resin (c) is If the amount is too small or too large, the effect of improving the adhesive performance of the adhesive layer cannot be sufficiently exhibited. Moreover, when the compounding amount of the tackifying resin (c) is too large, the extrusion moldability of the obtained pressure-sensitive adhesive composition deteriorates.

Further, the pressure-sensitive adhesive composition which forms the pressure-sensitive adhesiveness of the pressure-sensitive adhesive article of the present invention may contain a non-aromatic softening agent (d) for rubber. Examples of such a non-aromatic softening agent for rubber (d) include paraffin-based process oil, naphthene-based process oil, white oil,
Examples thereof include mineral oils, oligomers of ethylene and α-olefins, paraffin wax, liquid paraffin, isoprene and / or butadiene oligomers, and of these, paraffin-based process oils are preferable. These non-aromatic softening agents for rubber (d) may be used alone or in combination of two or more.

When the non-aromatic softening agent for rubber (d) is blended in the pressure-sensitive adhesive composition, the blending amount is 200 with respect to 100 parts by mass of the hydrogenated block copolymer (a) as the base polymer. It is preferable to use within the range of not more than parts by mass in order to obtain good adhesive performance. If the amount of the non-aromatic rubber softening agent (d) is too large, the adhesiveness of the pressure-sensitive adhesive layer may decrease. The blending amount of the preferable softening agent (d) for non-aromatic rubber is within the range of 180 parts by mass or less with respect to 100 parts by mass of the hydrogenated block copolymer (a).

The pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer of the pressure-sensitive adhesive article of the present invention may be, for example, calcium carbonate, clay, titanium oxide, talc, if necessary, within the range not impairing the gist of the present invention. It may contain an inorganic filler such as silica; a heat antiaging agent; a light stabilizer; an antistatic agent; a flame retardant and the like.

Such a pressure-sensitive adhesive composition can be prepared by a conventional method as a composition having an appropriate flowability and capable of being extruded by heating.

Next, a method of forming the adhesive article will be described.

The pressure-sensitive adhesive article of the present invention can be obtained by extrusion-molding the above-mentioned pressure-sensitive adhesive composition on an appropriate substrate for forming a pressure-sensitive adhesive article to form a pressure-sensitive adhesive layer. The material and shape of the base material in this case are not particularly limited, and examples thereof include films and sheets made of synthetic resin such as polyethylene, polypropylene and polyester; cloth such as woven cloth and non-woven cloth; metal foil; paper, wood; leather, etc. Is mentioned.

In the extrusion molding, a predetermined amount of polyethylene (b), a tackifying resin (c) and, if necessary, a non-aromatic rubber softening agent (d) with respect to the hydrogenated block copolymer (a). And other desired components are melt-kneaded using a kneader such as a single-screw extruder, a twin-screw extruder, a kneader, a Banbury mixer, and the obtained adhesive composition is extruded on a substrate in a molten state. A method can be mentioned. When the base material is extrudable, the sticky article may be obtained by coextrusion with the base material.

The thickness of the adhesive layer in the adhesive article of the present invention is not particularly limited, but is usually in the range of 30 to 150 μm.

The adhesive article thus obtained is used as an adhesive tape, an adhesive sheet, etc., for example, for industrial applications such as electricity, automobiles, construction and various medical applications, as well as for dust collecting rolls, sheets, It can be used in a wide range of industrial fields such as household products such as mats.

[0041]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

Reference Example (Production of Hydrogenated Block Copolymer) By using s-butyllithium as a polymerization initiator and sequentially adding a mixture of styrene, isoprene and butadiene in a predetermined mass ratio in cyclohexane, anionic polymerization is carried out. , A block copolymer was produced, and the obtained block copolymer was added to triethylaluminum / cyclohexane in cyclohexane.
A hydrogenated block copolymer (a) having the physical properties shown in Table 1 is obtained by carrying out a hydrogenation reaction at 70 ° C. in a hydrogen pressure atmosphere of 0.8 MPa using a nickel octylate catalyst.
(A1 to a5) were obtained.

[0043]

[Table 1]

Example 1 Hydrogenated block copolymer (a) shown in Table 1 having a styrene content of 30% by mass, a hydrogenation rate of 98% and a number average molecular weight of 90,000, a hydrogenated block copolymer (a2), and polyethylene. As (b), the melt flow rate is 5.0 (g / 10
Min) low density polyethylene (trade name "Novatech LC5
03 ”manufactured by Japan Polychem Co., Ltd., hydrogenated petroleum resin manufactured by Arakawa Chemical Industry Co., Ltd. as a tackifying resin (c) (trade name“ ALCON P ”).
-100 ") and a predetermined amount of paraffinic process oil manufactured by Idemitsu Kosan Co., Ltd. (trade name" Diana Process Oil PW-90 ") as a non-aromatic rubber-based softening agent were used in the composition shown in Table 2.

Using a polyester (PET) film having a thickness of 50 μm as a base material, the composition having the above composition was put into a T-die type film forming machine (90 mmφ, L / D: 25, die width: 1040 mm), An adhesive film was obtained as an adhesive article in which an adhesive layer having a thickness of 30 μm was extruded and formed into a film on one side of a PET film. The die temperature at this time was 230 ° C. and the line speed was 50 m / min.

The adhesive performance of the obtained adhesive film was measured by the following method, and the results are shown in Table 2. [Adhesiveness (tackiness)]: Determined by a ball tacking method according to JIS Z0237 under an ambient temperature of 25 ° C. The larger the value (ball tack number), the better the tackiness. [Holding power (creep test)]: Determined according to JIS Z0237. That is, an adhesive film cut into a length of 25 mm and a width of 25 mm is cut into a cold-rolled stainless steel plate (SUS
No. 304), and the adhesive film was held and fixed so that the film surface of the adhesive film was vertical, and a load of 1 kgf was hung on the central part of the lower end of the adhesive film to form an adhesive film at an ambient temperature of 40 ° C. The time required for peeling and falling (falling time: seconds) was measured. In addition, in the case where no drop was observed after 4 minutes, the distance (shift distance: mm) in which the adhesive film was vertically displaced from the position where the adhesive film was first attached was measured. [Adhesive strength]: Determined according to JIS Z0237. That is, an adhesive film cut into a length of 10 mm and a width of 20 mm is adhered to a cold rolled stainless steel plate (made of SUS304) and adhered under the conditions of an ambient temperature of 25 ° C., a peeling angle of 180 ° and a pulling speed of 300 mm / min. The adhesive strength when the film was peeled off was determined. Examples 2 and 3 and Comparative Examples 1 to 3 In Example 1, the hydrogenated block copolymer (a) was replaced with (a2), and various modifications were made as shown in a1 to a5 of Table 1 and the compounding amounts thereof. In the same manner as in Example 1, except that the blending amount of polyethylene (b), the type and blending amount of tackifying resin (c), and the blending amount of non-aromatic softening agent (d) were changed as shown in Table 2. To obtain an adhesive film.

The adhesive performance of the obtained adhesive film was evaluated in the same manner as in Example 1, and the results are also shown in Table 2.

[0048]

[Table 2]

From Table 2, in Examples 1 to 3 according to the present invention, it was possible to obtain adhesive films having excellent adhesive performance. On the other hand, in Comparative Example 1 in which the amount of the tackifying resin (c) was small, the ball tack number was 3 and the tackiness was poor.

Even when the compounding amount of the tackifying resin (c) is increased, when the hydrogenated block copolymer (a) having a molecular weight smaller than the number average molecular weight specified in the present invention is used, As shown in Comparative Example 2, the adhesive force is good, but the tack performance represented by tackiness and creep resistance is insufficient.

Further, in the composition shown in Comparative Example 3, Example 1 was used.
An attempt was made to produce a pressure-sensitive adhesive film by the same procedure as in 1. However, the extrusion moldability of the pressure-sensitive adhesive composition was poor, and a pressure-sensitive adhesive layer having a uniform thickness could not be formed on the PET film.

[0052]

EFFECTS OF THE INVENTION According to the present invention, a hot-melt pressure-sensitive adhesive containing a hydrogenated product of a block copolymer having a polymer block made of an aromatic vinyl monomer and a polymer block made of a conjugated diene monomer as a base polymer is used. It is possible to provide a pressure-sensitive adhesive article having an improved pressure-sensitive adhesive layer formed on a substrate, the pressure-sensitive adhesive article having improved adhesive performance.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Atsushi Oishi             36 Towada Stock Exchange, Kamisu Town, Kashima District, Ibaraki Prefecture             Inside the company Kuraray (72) Inventor Masao Ishii             12-1239 Umeda, Kita-ku, Osaka City, Osaka Prefecture             Inside the ceremony company Kuraray F term (reference) 4J004 AA02 AA04 AA05 AA06 AA07                       AA18 AB01 AB03 CA02 CA04                       CA06 CA08 CB01 CB02 GA01                 4J040 BA202 DA021 DA022 DB022                       DM011 DM012 DN032 JA09                       JB01 JB09 KA26 LA01 LA06

Claims (2)

[Claims] 1. (a) Two or more polymer blocks A composed of an aromatic vinyl monomer, and a conjugated diene monomer, and at least 70% of carbon-carbon double bonds based on the conjugated diene monomer are hydrogenated. 1 or more polymer blocks B produced, the content of the polymer block A is in the range of 3 mass% or more and 70 mass% or less, and the number average molecular weight is in the range of 50,000 or more and 150,000 or less. With respect to 100 parts by mass of the hydrogenated block copolymer in (b)
A pressure-sensitive adhesive composition containing 10 parts by mass or more and 150 parts by mass or less of polyethylene, and (c) 50 parts by mass or more and 300 parts by mass or less of a tackifying resin. 2. An adhesive article comprising an adhesive layer formed by extruding the adhesive composition according to claim 1 on a substrate.