JPH021782A - Tacky adhesive composition - Google Patents

Abstract

PURPOSE:To provide a novel tacky adhesive composition containing a conjugated diene rubber and a hydrogenated copolymer of a cyclopentadiene-type monomer and isoprene and having excellent tackiness and adhesivity. CONSTITUTION:The objective composition contains (A) a resin produced by hydrogenating a resin obtained by the thermal polymerization of (i) 40-85wt.% of a cyclopentadiene-type monomer and (ii) 15-60wt.% of isoprene, having a softening point of 60-150 deg.C and a bromine value of <=10 and containing <=2wt.% (preferably <=1wt.%) of polymer having a molecular weight of >=5,000 in terms of polystyrene and (B) a conjugated diene rubber. The amount of the component A is 30-250 pts.wt. (preferably 50-200 pts.wt.) per 100 pts.wt. of the component B.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a novel adhesive composition, and more specifically,
The present invention relates to a pressure-sensitive adhesive composition having excellent tackiness and adhesive force, which contains as a tackifier a hydrogenated resin obtained by copolymerizing a cyclopentadiene monomer and isoprene by a specific method.

(Prior Art) Adhesives based on conjugated diene rubbers such as natural rubber, polyisoprene rubber, and styrene-butadiene copolymers have been widely used in various applications such as adhesive tapes and adhesive labels. Tackifiers for these conjugated diene rubbers include petroleum hydrocarbon resins such as aliphatic hydrocarbon resins, aromatic hydrocarbon resins, and aliphatic/aromatic copolymer hydrocarbon resins; polyterpene resins, and rosin. Natural tackifier resins such as esters have been used, but these resins are all colored pale yellow to brown and have the problem of not necessarily being sufficiently stable against heat and ultraviolet rays.

For this reason, aromatic hydrocarbon resins and cyclopentadiene hydrocarbon resins must be hydrogenated for applications such as adhesive tapes manufactured using transparent support films such as cellophane paper, stretched polypropylene films, and polyester films. Colorless and transparent resins obtained by this process have come to be used as tackifiers.

However, the adhesive properties of adhesive compositions obtained using these hydrogenated hydrocarbon resins are not necessarily sufficient compared to those using conventional tackifier resins, especially in terms of tackiness and adhesive strength. There was a problem.

(Problems to be Solved by the Invention) An object of the present invention is to obtain a pressure-sensitive adhesive composition using a conjugated diene rubber as a paste, which has improved the above drawbacks.

As a result of intensive studies to achieve this objective, the present inventors have found that by blending a specific hydrogenated hydrocarbon resin into a conjugated diene rubber, an adhesive composition with excellent tackiness and adhesive strength can be obtained. Based on this finding, the present invention was completed.

(Means for Solving the Problems) According to the present invention, (1) (A) 40 to 85% by weight of cyclopentadiene monomer and 15 to 15% by weight of isoprene;
60% by weight of a hydride of a thermopolymerized resin with a softening point of 6.
0 to 150°C, a bromine number of 10 or less, a hydrogenated carbonized 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 conjugated diene rubber. Advantageous adhesive compositions are provided.

The constituent types and elements of the present invention will be explained in detail below.

(Hydrogenated Hydrocarbon Resin) In the thermally polymerized resin of the present invention, a cyclopentadiene monomer and isoprene 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. Good, but 1.3
- Even if linear conjugated dienes other than isoprene such as pentadiene and 1,3-butadiene are used, adhesive compositions with excellent tackiness and adhesive strength can be obtained depending on the hydrogenated hydrocarbon resin obtained from them. The purpose of the invention cannot be achieved.

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.
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 40 to 85% by weight, preferably tj, 5o to 80% by weight.
If this ratio is less than 400% by weight, the resin yield will drop significantly and only a semi-solid or oily polymer will be obtained, which is not preferred. On the other hand, if this ratio exceeds 85% by weight, it will be difficult to control the reaction, and even if the reaction is diluted with a solvent, the softening point of the resin will rise significantly, resulting in an adhesive that can be obtained using the hydride. The composition is unable to exhibit sufficient tackiness.

The proportion of isoprene in the monomer mixture is 15-60% by weight, preferably 20-50% by weight! -%, and when this ratio is less than 15% by weight, it is possible to obtain a resin in which the content of high molecular weight polymers having a polystyrene equivalent molecular weight of 5000 or more is 2% by weight 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, which is not preferable.

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.
The content of the high molecular weight polymer having a molecular weight of 00 or more is 2% by weight or less, but it further improves the tackiness and adhesive force of the adhesive composition obtained by blending it with the conjugated diene rubber of component (B). For this purpose, the content of high molecular weight polymer must be 1
It is particularly preferable that the amount is less than % by weight.

(Conjugated diene rubber) The conjugated diene rubber used as the component (B) in the present invention is a synthetic rubber containing natural rubber or a conjugated diolefin as a constituent component.

Specific examples of the latter include, but are not limited to, polyingrene, polybutadiene, and styrene-butadiene copolymers.

The above synthetic rubber can be produced by a known method such as a solution polymerization method or an emulsion polymerization method. Further, the molecular weight of the conjugated diene rubber is not particularly limited, but one having a 2-viscosity (ML + +4/10 DC) of 60 or more is usually used.

(Blending ratio) In the present invention, the hydrogenated hydrocarbon resin of the component (A) and the component (B
) component with the conjugated diene rubber is not necessarily uniform depending on the type of support for the adhesive or the desired field of application, but it is generally 100% of the conjugated diene rubber.
30 to 250 parts by weight of hydrogenated hydrocarbon resin,
Preferably, 50 to 200 parts by weight is blended.

Furthermore, in the present invention, other base polymers and tackifiers may be used in combination with the conjugated diene rubber and the hydrogenated hydrocarbon resin, as long as they do not essentially impede the effects of the present invention. It is also possible to blend softeners, antioxidants, pigments, fillers, etc.

(Method for manufacturing the composition) The method for manufacturing the composition of the present invention is not particularly limited, and mechanical mixing methods using rolls, Banbury mixers, etc. are also used, but usually conjugated diene rubber A method is adopted in which the hydrogenated hydrocarbon resin and, if necessary, other compounding agents are dissolved in a suitable solvent to form a solution, and the solution is uniformly mixed by stirring.

Solvents used in this method include pentane,
Aliphatic hydrocarbons such as hexane and heptane; toluene,
Examples include aromatic hydrocarbons such as xylene; alicyclic hydrocarbons such as cyclohexane; and halogenated hydrocarbons such as trichloroethylene, but are not limited to these. Mixing of the components of the adhesive composition in a solution is usually carried out at room temperature, but may be carried out at an elevated temperature in order to lower the viscosity of the solution.

Various adhesive tapes and adhesive labels can be manufactured by uniformly applying the solution of the adhesive composition obtained in this way onto a support such as paper, cellophane paper, or plastic film using a coating machine and drying.

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

Reference example 1 An autoclave equipped with a stirrer was heated at a temperature of 260°C and a pressure of 1
0 kyc! ! Hold at L″G, with an average residence time of 4
The raw materials shown in Table 1 are passed through continuously, or the raw materials are charged into the same autoclave and reacted at a temperature of 260°C for 4 hours, and then unreacted monomers are removed by distillation.
The low polymer and reaction solvent were distilled off to obtain a pale yellow transparent hydrocarbon resin. The softening point of the obtained resin was determined according to JIS K-
The hue was measured according to the ring and ball method specified in J.
It was measured by Gardner chromaticity as specified in IS K-5400, and the bromine number was measured by titration method as specified in O3K-2543. 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 60 kg/cm"G, reaction temperature 200
A hydrogenation reaction was carried out at a temperature of 3 hours for a reaction time of 3 hours. 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
Calculations were made based on a molecular weight distribution curve measured using LC-802A (Tosoh Corporation) and a calibration curve previously determined from the analysis results of standard polystyrene of known molecular weight. Column G-400DH packed with polystyrene gel was used for measurement.
and G-2000H in combination, column temperature 40℃
, carrier (tetrahydrofuran) flow rate t3mt/m
Measurements were carried out under conditions of in.

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 *Hydrogenated resins AH-PH are resins obtained by hydrogenating resins A-F, respectively.

Example 1 Natural rubber (Beer crepe, Mooney viscosity (ML++4)
/+ooo℃) 60) Io parts, 100 parts of the hydrogenated hydrocarbon resin shown in Table 3, and 1 part of an antioxidant (Sumilyzer BHT, Sumitomo Chemical ff) were dissolved and mixed in toluene to obtain a non-oxidizing fraction. An adhesive composition solution with a concentration of 17% was prepared.

Next, this solution was applied to a polyester film having a thickness of 25 μm so that the adhesive 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.
At 3°C, stick a 10 cIrL length of adhesive tape with the adhesive side up on a stainless steel plate-like slope with an inclination angle of 30 degrees. Steel balls of 30 sizes from 3/32 inch to 1 inch in diameter are rolled from the L position at an initial speed of 0, and the size of the largest diameter ball that stops on the adhesive tape is indicated, and the adhesive strength is determined according to JIS. According to Z-0237, adhere adhesive tape to a stainless steel plate polished with No. 280 water-resistant abrasive paper to a width of 10 mm x length of 100 nm, and
Measured by peeling in a direction of 180 degrees at a speed of 20 o mtn 1 minute at 3°C, and the holding force was determined according to JIS Z-025.
25 audience xio on a stainless steel plate treated in the same way according to 7.
Paste adhesive tape so that the areas of mIB are in contact with each other, and
A load of 1 kg was applied at 0° C., and the time required for the adhesive tape to fall off the stainless steel plate was measured.

The results are shown in Table 3.

Table 3: 100 parts of Nippon Zeon ■), 80 parts of hydrogenated hydrocarbon resin shown in Table 4, and antioxidant (Sumilizer BHI)
The adhesive properties were evaluated in the same manner as in Example 1, except that 1 part of Sumitomo Chemical Co., Ltd.) was blended to prepare the adhesive. The results are shown in Table 4.

From the results in Table 4 and Table 3, it is clear that the adhesive composition of the present invention consisting of hydrogenated hydrocarbon resin and natural rubber exhibits high tackiness and adhesive strength, and has well-balanced adhesive properties. It can be seen that if a hydrogenated hydrocarbon resin in which the proportion of a polymer having a molecular weight of 5,000 or more exceeds 2 units is used as a tackifier, an adhesive having sufficient tackiness and adhesive force cannot be obtained.

Example 2 Styrene-butadiene copolymer (Nipole 1502) From the results in Table 4, the adhesive composition comprising the hydrogenated hydrocarbon resin of the present invention and the styrene-butadiene copolymer exhibited high tackiness and adhesive strength. ,) Although it has good adhesive physical properties, when a hydrogenated hydrocarbon resin with a proportion of polymer with a molecular weight of 5,000 or more exceeds 2% is used as a tackifier, it becomes an adhesive with extremely poor tackiness and adhesive strength. It can be seen that only .

(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. -804=

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, an adhesive composition comprising a hydrogenated hydrocarbon resin having a molecular weight of 5,000 or more in terms of polystyrene and a polymer content of 2 weight or less, and (B) a conjugated diene rubber.