JPH01165684A - Self-adhesive composition - Google Patents

Abstract

PURPOSE:To obtain the title composition having excellent tackiness, by mixing a tackifier comprising a specified hydrogenated hydrocarbon resin with a base polymer comprising a specified thermoplastic elastomer. CONSTITUTION:A resin prepared by thermal polymerization of 40-85wt.% cyclopentadiene monomer and 15-60wt.% isoprene is hydrogenated to give a hydrogenated hydrocarbon resin (A) which has a softening point of 60-150 deg.C and a bromine number of 10 or less and contains 2wt.% or less polymer having a molecular weight (in terms of PS) of 5,000 or higher. Component A is mixed with a thermoplastic elastomer (B) consisting of polystyrene blocks and polyisoprene blocks or hydrogenated polybutadiene blocks to give an objective self-adhesive. Although it is well known that component B can be used as a base polymer for a self-adhesive and for a hot-melt adhesive, a hydrogenated hydrocarbon resin conventionally used as tackifier has an insufficient ability to plasticize component B, and as a result the self-adhesive composition thus obtained has such a shortcoming that it lacks tackiness. The use of component A can provide excellent tackiness.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a novel pressure-sensitive adhesive composition, and more specifically, to a novel pressure-sensitive adhesive composition obtained by copolymerizing a cyclopentadiene monomer and isoprene by a specific method. The present invention relates to a novel pressure-sensitive adhesive composition having excellent tackiness, which contains a hydride of a resin obtained by using a hydride resin as a viscosity-imparting agent.

(Prior Art) It is well known that a thermoplastic nidistomer consisting of a polystyrene block and a polyimprene block or a hydrogenated polybutadiene block can be used as a base polymer for pressure-sensitive adhesives and hot melt adhesives.

Tackifiers for these thermoplastic elastomers include:
Tackifier resins that are well compatible with the polyisoprene blocks or hydrogenated polybutadiene blocks of these elastomers, such as aliphatic hydrocarbon resins or polyterpene resins, can be used, but especially those produced by the hot melt process can be used. Regarding adhesives and hot melt adhesives,
Hydrogenated hydrocarbon resins are often used as tackifiers to impart excellent hue, thermal stability, and weather resistance.

However, conventional hydrogenated hydrocarbon resins do not necessarily have sufficient ability to plasticize the above-mentioned thermoplastic nidistomers.
The adhesive composition obtained using this method has a drawback of poor tackiness.

(Problems to be Solved by the Invention) Therefore, the inventors of the present invention have carried out intensive studies to improve the drawbacks of adhesive compositions obtained by using hydrogenated hydrocarbon resin as a tackifier. discovered that a hydrogenated hydrocarbon resin with a small content of high molecular weight polymers can be obtained by hydrogenating a hydrocarbon resin obtained by continuous thermal polymerization of a monomer mixture of a specific composition, It was discovered that a pressure-sensitive adhesive composition with excellent tackiness could be obtained by blending this into a thermoplastic elastomer consisting of a polystyrene block and a polyisoprene block or a hydrogenated polybutadiene block, and thus completed the present invention. It has arrived.

(Means for Solving the Problems) Thus, according to the present invention, (A) a hydrogenated product of a thermopolymerized resin containing 40 to 85% by weight of a cyclopentadiene monomer and 15 to 60% by weight of isoprene, Softening point 60-1
50°C, a bromine number of 10 or less, a hydrogenated carbonized resin with a molecular weight of 5000 or more in terms of polystyrene and a polymer content of 2% or less, and (B) a polystyrene block and a polyisoprene block or a hydrogenated polybutadiene block. Provided is a pressure-sensitive adhesive composition comprising a thermoplastic nidistomer comprising:

Hereinafter, the constituent elements of the present invention will be explained in detail.

(Hydrogenated Hydrocarbon Resin) In the thermally polymerized resin of the present invention, a cyclopentadiene monomer and inbrene are used as a monomer mixture. Cyclopentadiene monomers include lower alkyl-substituted cyclopentadiene such as methylcyclopentadiene and ethylcyclopentadiene, as well as dimers, dimers, and co-dimers of cyclopentadiene or its alkyl-substituted derivatives. Lower Diels-Alder adducts such as mercury are included. Isoprene used in the present invention can also be used in the form of a codimer with cyclopentadiene or its alkyl substituted product.

Of course, in addition to cyclopentadiene or its alkyl substituted product, copolymerizable monomers such as indene, methylindene, coumaron, and styrene may coexist as long as the effects of the present invention are not essentially impaired. However, even if a linear conjugated diene such as 1j-pentadiene or 1,3-butadiene is used instead of isoprene, the pressure-sensitive adhesive composition with excellent tackiness may not be obtained depending on the hydrogenated hydrocarbon resin obtained from them. The purpose of the present invention, which is to obtain

In the present invention, a monomer mixture consisting of a cyclopentadiene monomer and isoprene is heated at 240 to 300°C, preferably 250 to 280°C, in the absence of a radical initiator.
A resin obtained by thermal polymerization is used. At this time, it is preferable to use a thermally polymerized resin obtained by continuously thermally polymerizing a monomer mixture, and depending on batch polymerization, the content of a polymer having a polystyrene equivalent molecular weight of 5000 or more is 2% by weight.
Below, it is difficult to obtain a resin of preferably 1% by weight or less.

The hydrogenated hydrocarbon resin of the present invention can be prepared by a known method such as nickel, palladium, cobalt, etc.
It can be obtained by hydrogenation using a platinum- or rhodium-based catalyst in the presence or absence of a diluent at a temperature of 150 to 300°C, and has a bromine number of 10 or less and a Gardner color. It has a temperature of 1 or less and a softening point of 60 to 150°C.

The ratio of the cyclopentadiene monomer in the monomer mixture is in the range of 40 to 85% by weight, preferably 50 to 80i31%, and if this ratio is less than 40% by weight, the resin yield will be significantly reduced. This is not preferable because it results in a lowering of the polymer and a semi-solid or oily polymer. On the other hand, if this ratio exceeds 85% by weight, it will be difficult to control the reaction, even if the reaction is diluted with a solvent.
The softening point of the resin increases significantly, and a pressure-sensitive adhesive composition obtained using the hydride cannot exhibit sufficient tackiness.

The proportion of isoprene in the monomer mixture is in the range of 15 to 60% by weight, preferably 20 to 50% by weight, and when this proportion is less than 15% by weight, a high molecular weight polymer with a polystyrene equivalent molecular weight of 5000 or more is used. The content rate is double f
! :% or less, preferably 1% by weight or less; on the other hand, if this ratio exceeds 60% by weight, the yield of the resin will drop significantly and the softening point of the resin will drop significantly. Therefore, it is not desirable.

The hydrogenated hydrocarbon resin of the component (A) in the present invention has a molecular weight distribution such that the molecular weight in terms of polystyrene is 50.
In order to further improve the tackiness of the adhesive composition obtained by blending it with the thermoplastic nidistomer of component (B), the content of the high molecular weight polymer having a molecular weight of 00 or more is 2% by weight or less. It is particularly preferable that the content of high molecular weight polymer is 1% by weight or less.

(Thermoplastic elastomer) The thermoplastic elastomer, which is another basic component of the composition of the present invention, is a block copolymer derived from styrene and isoprene, or a block copolymer derived from styrene and butadiene. It is a compound whose block structure has the general formulas (AB)m, (AB)I! 1-IA
Also, Ir1(A-B)nX (in the formula, the person is substantially a polystyrene block, B is substantially a polyisoprene block or hydrogenated polybutadiene block, and It is a linear or branched block copolymer representing the residue of a functional coupling agent, m is an integer from 2 to 10, and n is an integer from 2 to 7. Mffi used in the present invention
The styrene unit content of the elastomer is 10 to 55 weight tons.
%, preferably 10 to 40% by weight, and the weight average molecular weight is in the range of 25.000 to 2.000,000, preferably 4Q, 000 to 1,000,000. In the present invention, one type of block copolymer may be used alone or two or more types may be used in combination.

The linear or branched block copolymer used in the present invention is produced by a method known in the art. To give an example of the production method, styrene monomer is first polymerized in the presence of a lithium-based initiator. After the polystyrene block is formed, the imprene monomer is added to form the polyisoprene block following the polystyrene block. Furthermore, by sequentially polymerizing styrene monomer and isoprene monomer, (polystyrene (S)-polyisoprene (I)) m-type or (S-I
) An m-1s type linear block copolymer is obtained.

In addition, in the method for producing the linear block copolymer,
-I by making a block copolymer and reacting this block copolymer with terminal lithium with a polyfunctional compound having 2 to 7 reactive groups that reacts with terminal lithium (branched s-Bnx type). block copolymers can be obtained.

Furthermore, a polystyrene-hydrogenated polybutadiene block copolymer can be obtained by hydrogenating the polystyrene-polybutadiene block copolymer by a known method.

The block copolymer used in the present invention does not necessarily have to be a complete block copolymer, and may contain incomplete block polymer portions as long as it is a thermoplastic diastereomer.

(Blending ratio) The blending ratio of thermoplastic elastomer and hydrogenated hydrocarbon resin depends on the desired application field such as pressure-sensitive adhesives and hot melt adhesives, or even in the case of the same pressure-sensitive adhesive or adhesive, depending on the type of adherend. Although not necessarily uniform, generally 10 to 500 M parts of hydrogenated hydrocarbon resin, preferably 50 to 300 M parts, per 100 parts by weight of thermoplastic elastomer.
Parts by weight are blended.

Furthermore, in the present invention, in addition to the thermoplastic elastomer and the hydrogenated hydrocarbon resin, other base polymers and tackifiers may be used in combination as long as they do not essentially impede the effects of the present invention. Softeners such as process oils, waxes such as paraffin wax, antioxidants, pigments, fillers, etc. that are commonly used in the production of agent compositions can also be blended.

(Method for producing composition) The composition of the present invention is produced according to any method. For example, each compounded component can be put into a blade mixer equipped with blades with an appropriate shape for mixing, heated and kneaded, and continuously mixed using an extruder-type mixer equipped with a -shaft or twin screws. It can also be manufactured manually. Alternatively, the adhesive solution can be prepared by stirring and mixing each component in the presence of a solvent such as toluene.

The solution type, hot melt type, etc. adhesive composition thus obtained can be applied uniformly to a desired base material using a coating machine to produce various adhesive tapes and adhesive label products. After heating and kneading, the mixture can be placed in a container such as a paper drum, cooled, and then remelted for use in hot melt adhesives.

(Example) The present invention will be described in more detail with reference to Examples below. In addition, parts and parts in Examples, Control Examples, and Reference Examples are based on weight unless otherwise specified.

Reference Example 1 An autoclave equipped with a stirrer was maintained at a temperature of 260'O and a pressure of 10 kg/cm''G, and the raw materials shown in Table 1 were continuously passed through it with an average residence time of 4 hours, or the same autoclave was After the raw materials were charged and reacted for 4 hours at a temperature of 260°C, unreacted monomers, low polymers, and reaction solvent were distilled off to obtain a pale yellow transparent hydrocarbon resin. JIS softening point
The measurement was performed according to the ring and ball method specified in JIS K-2531, the hue was measured according to the Gardner chromaticity specified in JIS K-5400, and the bromine number was measured according to the titration method specified in JIS K-2545. The results are shown in Table 1 along with the resin yield.

Table 1 100 parts of the hydrocarbon resin thus obtained, 100 parts of cyclohexane and a hydrogenation catalyst (stabilized nickel N-
113M (manufactured by JGC Chemical) in an autoclave, hydrogen pressure 60ky7cm"G% reaction temperature 200
゛Hydrogenation reaction was performed for O1 reaction time of 3 hours, and after the reaction,
The catalyst and solvent were removed from the reaction mixture to obtain a hydrogenated hydrocarbon resin. The properties of this resin were measured by a predetermined method, and the results are shown in Table 2.

The weight average molecular weight of the resin and the ratio of polymers with a molecular weight of 5000 or more are determined by high performance liquid chromatography (H
From the molecular weight distribution curve measured using LC-802A (manufactured by Toyo Soda ■), the detection value was determined in advance from the analysis results of standard polystyrene with a known molecular weight. Calculated based on 1 line.

Column G-400 packed with polystyrene gel was used for measurement.
Using a combination of 0H and G-200DH, the column temperature was 4.
0°C, carrier (tetrahydrofuran) flow rate t 3ml
Measurements were carried out under conditions of /min.

In addition to the results in Table 2, for reference, hydrogenated hydrocarbon resin A
Figure 1 shows the molecular weight distribution of H and DH.

Table 2 Example 1 100 parts of linear polystyrene-polyisoprene block copolymer (FinTac 3420, polystyrene content 14%, weight average molecular weight 220,000, manufactured by Nihon Ue On ■), No. 5
100 parts of the hydrogenated hydrocarbon resin shown in the table, paraffinic acetic oil (Fukol 205ON, manufactured by Fuji Kosan ■)
20 parts and 1 part of an antioxidant (Sumilizer BHT, manufactured by Sumitomo Chemical) were dissolved and mixed in toluene to obtain a non-volatile content concentration of 50.
A pressure-sensitive adhesive solution was prepared. Next, this solution was applied to a polyester film having a thickness of 25 μm so that the glue thickness was 25 μm to prepare an adhesive tape, and its tackiness, adhesive strength, and holding power were measured.

In addition, tackiness is 2 according to JIS Z-0237.
Adhesive tape with a length of 10 cR was pasted with the adhesive side facing up on the slope of a stainless steel plate with an inclination angle of 50 degrees at 5°C.
Steel balls of 30 sizes from 5/32 inch to 1 inch in diameter are rolled from a position 10 cgL above the slope with initial velocity dust O, and the size of the ball with the largest diameter that stops on the adhesive tape is displayed. The force is 2 according to JIS Z-0257.
Width 101 on a stainless steel plate polished with No. 80 water-resistant abrasive paper.
Attach adhesive tape to 11x length 100*m, 2
The holding force was measured by peeling in a direction of 180 degrees at a rate of 200111/min at 3°C, and the holding force was determined according to JIS Z-0237.
Paste the adhesive tape so that the area of 011m touches,
A load of 1 ky was applied at 60'C, and the time required for the adhesive tape to fall off the stainless steel plate was measured.

The results are shown in Table 6.

From the results in Table 3, the adhesive composition containing the hydrogenated hydrocarbon resin of the present invention and the thermoplastic elastomer consisting of polystyrene blocks and polyisoprene blocks exhibits high tackiness, taking into account the softening point of the resin. When the molecule tht has well-balanced adhesive properties,
It can be seen that if a hydrogenated hydrocarbon resin in which the proportion of polymer of 5,000 or more exceeds 2% is used as a tackifier, it is not possible to obtain an adhesive having sufficient tackiness.

Example 2 Linear polystyrene-hydrogenated polybutadiene block copolymer (Krayton G1657, polystyrene content 14
%, weight average molecular weight 160,000, manufactured by Shell Chemical ■) 100 parts, 150 parts of the hydrogenated hydrocarbon resin shown in Table 4, 50 parts of paraffinic acetic oil (Fukol 205ON), and 1 part of antioxidant (Sumilizer BHT) The adhesive physical properties were evaluated in the same manner as in Example 1, except that the adhesive was prepared by blending the following. The results are shown in Table 4.

From the results in Table 4, it is clear that the adhesive composition containing the hydrogenated hydrocarbon resin of the present invention and the thermoplastic elastomer consisting of a polystyrene block and a hydrogenated polybutadiene block also exhibits high tackiness and a well-balanced adhesive composition. It can be seen that it has adhesive physical properties.

Reference Example 2 (8-I) Production of nX-type branched block copolymer A mixture of n-butane and cyclohexane as a solvent, n-butyllithium as an initiator, and diptyl ether as a reaction regulator were charged into an autoclave equipped with a stirrer. ,
After polymerizing styrene at 30 C for 1 hour, isoprene was introduced into the autoclave and the autoclave was heated to 50 C.
Polymerization was carried out at .degree. C. for 2 hours to produce an S-I block copolymer. Subsequently, silicon tetrachloride was added as a polyfunctional compound, and coupling was performed at 50°C for 2 hours. The resulting reaction solution was dropped into hot water to remove the solvent, and further dried using a hot air dryer to obtain a block copolymer sample. The resulting copolymer has substantially n
The polystyrene content was 19% and the weight average molecular weight was 200,000.

Example 3 100 parts of the branched block copolymer obtained in Reference Example 2, 5th
An adhesive was prepared by blending 100 parts of the hydrogenated hydrocarbon resin shown in the table, 20 parts of paraffinic process oil (Fukol 205ON) and 1 part of an antioxidant (Sumilizer BIT), and the adhesive physical properties were prepared in the same manner as in Example 1. was evaluated.

The results are shown in Table 5.

From the results in Table 5, it is clear that the hydrogenated hydrocarbon resin of the present invention and (S
It can be seen that the pressure-sensitive adhesive composition containing -I) QX-type branched block copolymer also exhibits high tackiness and has well-balanced pressure-sensitive adhesive properties.

(Effects of the invention) The adhesive composition obtained by the invention has excellent hue,
It has thermal stability and weather resistance, exhibits superior tackiness compared to conventional technology, and exhibits well-balanced adhesive properties when considering the softening point of the resin.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the molecular weight distribution of hydrogenated hydrocarbon resin. AH...Hydrogenated hydrocarbon resin DH used in the present invention
...Comparative Hydrogenated Hydrocarbon Resin Patent Applicant Nippon Zeon Co., Ltd.

Claims (1)

[Claims] (1) (A) A hydrogenated product of a thermally polymerized resin containing 40 to 85% by weight of a cyclopentadiene monomer and 15 to 60% by weight of isoprene, with a softening point of 60 to 150°C and a bromine number of 10.
Hereinafter, a hydrogenated hydrocarbon resin having a molecular weight of 5,000 or more in terms of polystyrene and a polymer content of 2% by weight or less, and (B) a thermoplastic elastomer consisting of a polystyrene block and a polyisoprene block or a hydrogenated polybutadiene block are used. An adhesive composition characterized by comprising: