JPS62506A - Hydrocarbon resin - Google Patents

Abstract

PURPOSE:To improve the compatibility with an adhesive base such as a thermoplastic resin or natural or synthetic rubber, by specifying the bromine value of a hydrocarbon resin obtained by hydrogenating a copolymer of a cyclopentadiene compound with a vinyl-substituted aromatic hydrocarbon. CONSTITUTION:A hydrocarbon resin obtained by hydrogenating a cyclopentadiene compound/vinyl-substituted aromatic hydrocarbon copolymer and has a bromine value of 3-7. Examples of said cyclopentadiene compounds which can be desirably used include cyclopentadiene and dicyclopentadiene. Examples of said vinyl-substituted aromatic hydrocarbons which can be desirably used include styrene, alpha-methylstyrene and vinyltoluene, among which styrene is preferable. The ratio between said two comonomers is preferably such that 80-30wt% cyclopentadiene compound is used per 20-70wt% vinyl-substituted aromatic hydrocarbon (the total being 100wt%).

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to hydrocarbon resins, and more specifically, they have excellent compatibility with thermoplastic resins or natural or synthetic rubbers, and are particularly suitable for use in pressure-sensitive adhesives and hot-pressure adhesives. This invention relates to hydrocarbon resins useful as tackifiers for melt-type adhesives.

[Prior art] Adhesives such as pressure-sensitive adhesives and hot-melt adhesives have a thermoplastic resin or natural or synthetic rubber as the main adhesive, and a tackifier and, if necessary, a plasticizer or filler. Most of the products are made by blending the following.

As this tackifier, a hydrocarbon resin is conventionally known, which is obtained by hydrogenating a copolymer obtained by copolymerizing cyclopentadiene and a vinyl-substituted aromatic hydrocarbon such as styrene. .

[Problem to be solved by the invention] Conventional hydrocarbon resins mainly include O~
Those having a bromine number of 3 are commonly used. This material certainly contributes to increasing the adhesive force, adhesive holding power, and thermal stability of adhesives, but it has poor compatibility with thermoplastic resins and natural or synthetic rubbers, especially rubbers, which are the main ingredients. There is an inconvenience. Therefore, when preparing an adhesive, first, this hydrocarbon resin and a main adhesive agent such as rubber are dissolved and mixed in a solvent such as pentane or benzene, and this mixture is applied to the area to be bonded and then dried. There was a problem in that it was necessary and extremely complicated from a process standpoint.

[Means for Solving the Problems] The present invention solves the conventional problems and provides hydrocarbons that have excellent compatibility with thermoplastic resins and natural or synthetic rubbers and are useful as tackifiers for adhesives. The purpose is to provide resin.

As a result of intensive studies focusing on the bromine number of the obtained hydrocarbon resin, the present inventors confirmed that the above object is achieved when the bromine number falls within the range described below, and completed the present invention. reached.

That is, the hydrocarbon resin of the present invention is a hydrogenated product of a cyclopentadiene compound-vinyl-substituted aromatic hydrocarbon copolymer, and is characterized by having a bromine number of more than 3 and less than or equal to 7. .

[Specific Description] As mentioned above, the hydrocarbon resin of the present invention is a hydrogenated product of a copolymer of a cyclopentadiene compound and a vinyl-substituted aromatic hydrocarbon, and has a bromine number of more than 3. , and is required to be 7 or less. When the bromine number is 3 or less, the compatibility of the hydrocarbon resin with the thermoplastic resin or natural or synthetic rubber decreases, which is not preferable. On the other hand, when the bromine number exceeds 7.

Although there is no problem of decreased compatibility as described above, there is a disadvantage that the thermal stability and weather resistance of the hydrocarbon resin itself are deteriorated. The preferred value of the bromine number is 3.5 to 6.0.

The hydrocarbon resin of the present invention is produced as follows.

That is, first, a copolymer containing the above-described cyclopentadiene compound and a vinyl-substituted aromatic hydrocarbon as copolymerization components is produced by a copolymerization reaction of the above-mentioned cyclopentadiene compound and a vinyl-substituted aromatic hydrocarbon.

The cyclopentadiene compound used at this time is
It is not particularly limited, and examples include cyclopentadiene, methylcyclopentadiene, ethylcyclopentadiene, dimers, trimers, or codimers thereof. Among them, cyclopentadiene and dicyclopentadiene are preferred. Further, as the cyclopentadiene compound, a mixed fraction obtained by thermal decomposition of petroleum may be used.The cyclopentadiene may be used as it is during the preparation, but dicyclopentadiene may be used as it is. The vinyl-substituted aromatic hydrocarbon used is not particularly limited, and examples include EVA, styrene, and α-methyl. Examples include styrene, vinyltoluene, and isopropylbenzene. Among these, styrene is preferred.

The composition ratio of these two copolymerization components is not particularly limited, but for example, the cyclopentadiene compound is 80 to 30% by weight, and the vinyl-substituted aromatic hydrocarbon is 20% by weight.
It is preferable to set the usage amount of each component so that the total amount is 100% by weight at 70% by weight.

The reaction conditions for this copolymerization reaction are as follows: 1 reaction degree is 220 to 320°C, preferably 250 to 300°C, reaction time is 1 to 8 hours, preferably 1.5 to 5 hours, and pressure is 0 to 30°C. kg/cnsG, preferably 5-20
kg/cydG. Further, during the reaction, a solvent such as xylene or toluene may be used as necessary.

Next, the thus obtained copolymer is hydrogenated to obtain a hydrogenated copolymer, that is, the desired hydrocarbon resin of the present invention. In this step, examples of catalysts used include old, Pd, and Go.
, Pt, and Rh-based catalysts. Further, during the reaction, a solvent such as cyclohexane or tetrahydrofuran may be used as necessary.The reaction conditions are preferably set to achieve the above-mentioned bromine number, and the reaction temperature is 130 to 300°C. Preferably,
The temperature is set at 150-260°C and the reaction time is set at 1-7 hours, preferably 2'-5 hours. Note that the degree of aromatic ring hydrogenation in this step is 80% or less. The Gardner chromaticity of the hydrocarbon resin obtained in this way is
1 or less, and its softening point is about 50-185°C.

[Example] Examples 1 to 3, Comparative Examples 1 to 3 Inner volume 200 g of cyclopentadiene (prepared with dicyclopentadiene) and 2 QOg of xylene were charged into a single-cross autoclave, and the temperature was 260 g.
The copolymerization reaction was carried out for 2 hours at °C1 pressure of 12 kg/cr+fG. As a result, 360 g of copolymer was obtained. This material had a softening point of 102°C, a bromine number of 57, and a Gardner chromaticity of 5.

The copolymer thus obtained was subjected to hydrogenation under the conditions indicated to obtain the desired hydrocarbon resin. Further, as a hydrogenation catalyst, a Pd-silica alumina catalyst containing 0.5% by weight of Pd was used.

The softening point, bromine number, hue (Gardner chromaticity), and degree of aromatic ring hydrogenation of the hydrocarbon resin are shown in the table.

Furthermore, the following evaluation tests were conducted on these hydrocarbon resins.

(1) Compatibility evaluation test Natural rubber and 5BR (11507S manufactured by Japan Synthetic Rubber)
The compatibility of hydrocarbon resin with BR) was investigated. That is, a solution made by uniformly mixing natural rubber (or 5BR), toluene, and hydrocarbon resin at a weight ratio of 1:1+1 is applied to a glass plate, and the transparency after removing toluene is evaluated by visual observation. 0 for transparent, × for opaque
1 The middle point between the two is indicated by Δ.

(2) Thermal stability evaluation test The hydrocarbon resin sample log was collected in an SOS open container with an internal volume of 20 cc, and the viscosity change after leaving the container in a hot air dryer at 150°C for 20 hours was measured using a B-type viscometer. The viscosity increase rate (%) with respect to the initial viscosity was calculated.

3) Weather resistance evaluation test hydrocarbon resin sample +00m+sX 50mmX 5
A resin plate was obtained by melting the resin in a metal sheet mold and then cooling it. For this resin plate,
After conducting a 100-hour weather test using a xenon weather tester (Toyo Seiki Seisakusho Department), the changes in coloring were evaluated by visual observation. Indicated.

The results of the above evaluation tests (1) to (3) are listed together in the table.

[Effects of the Invention] As is clear from the above explanation, the hydrocarbon resin of the present invention has excellent compatibility with thermoplastic resins and natural or synthetic rubber, especially rubber, and has excellent thermal stability. Since it also has excellent weather resistance, it is extremely useful as a tackifier for pressure-sensitive adhesives and hot-melt adhesives, and has great industrial value.

Claims (1)

[Claims] A hydrocarbon resin, which is a hydrogenated product of a cyclopentadiene compound-vinyl-substituted aromatic hydrocarbon copolymer, and has a bromine number of more than 3 and less than or equal to 7.