JPH03166286A - Elastic sealant composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition giving excellent water-stopping effect and having high heat-resistance, stability and weather-resistance by mixing an SEBS rubber consisting of a specific block copolymer with a rubber softener at a specific ratio. CONSTITUTION:The objective composition is a mixture composed of (A) 15-30wt.% of an SEBS rubber consisting of a block copolymer having PS phase at both terminal phases and a hydrogenated polyolefin phase as the intermediate rubber phase and (B) 70-80wt.% of a rubber softener consisting of one or more substances preferably selected from process oil, straight asphalt having a penetration of >=100 and a liquid resin.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to an elastic sealing material composition used in the civil engineering and construction fields, and more specifically, for use in concrete joints, segment joints, Hume pipe joints, concrete joints, etc. No. 6 relates to a molded sealing material with excellent elasticity or a sealing material composition for hot injection used in box-force Rupert joints, etc. [Prior Art 1] Conventionally, in order to construct a structure such as a tunnel, a plurality of segments are joined to form a predetermined structure. Such structures include hume pipes and concrete box rubatos for burying various cables, gas pipes, water and sewage pipes, etc. in tunnels. All of these are installed underground, but they are also included in the above-mentioned structures, such as elevated railways and expressways installed above ground. Water sealing of joints such as concrete joints and segments of these structures has been recognized as an important problem, and a number of sealing materials have been provided. There are two types of sealing materials: those that are injected and those that are used as molding materials.
Injection types include non-vulcanized rubber, rubberized asphalt,
There are flexible materials such as asphalt. In addition, molding materials include synthetic resins, vulcanized rubber, and non-vulcanized rubber, but synthetic resin molding materials are embedded during concrete pouring and are mainly used to stop water in the batting area. Ru. Vulcanized rubber molding materials are often used for segment joints, and recently there is a type called water-swellable, which expands in response to water and increases its water-stopping effect. Non-vulcanized rubber molding material itself has adhesive properties, making it easy to apply to joints, etc., and it also swells when it absorbs water. [Problems to be solved by the invention] Although conventional injection-type sealants have excellent adhesion to concrete, they lack elasticity and are prone to plastic deformation, and because they are used after being heated and melted, they are non-vulcanized. Rubber or rubberized asphalt is easily decomposed by heat, often resulting in loss of rubber elasticity. Also,
For molded sealing materials, synthetic resins are used. It has poor adhesion to post-cast concrete such as vulcanized rubber, and lacks water-stopping properties. Non-vulcanized rubber is sticky and adheres well to concrete, but has drawbacks such as a lack of elasticity. [Means for Solving the Problems] The present invention has been made in order to solve the drawbacks of the above-mentioned prior art. That is, this is an elastic sealing material composition characterized by using a mixture consisting of 5 to 30% by weight of SEBS rubber and 70 to 85% by weight of a rubber softener. The SEBS (styrene-ethylene-butylene-styrene) rubber used in the present invention is called a styrene-based thermoplastic elastomer, and has a polystyrene phase in both terminal phases.
It is a block copolymer with a hydrogenated polyolefin as the rubber intermediate phase. The polystyrene end block and the rubber intermediate block form a two-phase structure without being mutually compatible. Among these, the polystyrene phase forms physical crosslinking points (domains) that function in the same way as crosslinking points in conventional vulcanized rubber at room temperature, giving the thermoplastic elastomer rubber elasticity. When the thermoplastic elastomer is heated above the glass transition point of polystyrene, the domains soften and fluidity increases, but when cooled, the domains reappear and exhibit rubber elasticity. Because of this structure, it can be easily heated and processed, and it also has many excellent physical properties such as high cohesive strength and high elasticity at low temperatures. As such styrene thermoplastic elastomer,
In addition to the SEBS rubber mentioned above, there are SBS (styrene-butadiene-styrene) rubber and SIS (styrene-isoprene-styrene) rubber. SEBS rubber has much better weather resistance and heat resistance than these rubbers.
Rubber softeners used in the present invention include process oil, straight asphalt, and liquid resin, which may be used alone or in combination with the SEBS rubber. These rubber softeners are used for the purpose of imparting plasticity and tackiness to rubber, and 70 to 85% by weight of rubber softeners are used for 15 to 30% by weight of SEBS rubber.
This is the mixing ratio of The amount of SEBS rubber used is 15% by weight.
If it is less than that, the softening point of the composition will be low and it is not practical. On the other hand, 3
If it exceeds 0% by weight, the viscosity of the composition increases extremely, making it unfavorable for handling. Also, the cost is too high and it is not economical. Process oil is a high-boiling fraction of petroleum, consisting of saturated or inert unsaturated hydrocarbons, and has a hue ranging from colorless to fluorescent dark green, and is regulated by viscosity, specific gravity, and aniline point. ing. There are three main types: paraffinic, naphthenic, and aromatic, and any of these can be suitably used in the present invention. In addition, straight asphalt preferably has a penetration value of 100 or more, and this is a bituminous material obtained by subjecting crude oil to normal pressure/vacuum distillation equipment to remove light components, and has a total penetration degree of 100 to 120. .120~150,150~
200 and 200-300 can be used. The liquid resin is a natural or synthetic resin that is liquid at room temperature, such as a turpentine liquid resin made from pine resin or a liquid resin synthesized from petroleum, which is preferably used to impart stickiness to rubber. be able to. In the present invention, it is preferable to incorporate a filler into SEBS in order to reduce compounding costs, improve processability, and have a reinforcing effect on rubber. In this case, usually SE
For 100 parts by weight of the mixture of BS rubber and rubber softener,
The filler is blended in a range of 0 to 40 parts by weight. If the amount of filler added exceeds 40 parts by weight, the adhesive strength to concrete etc. will decrease, which is undesirable from a practical standpoint. Examples of the filler used include calcium carbonate, talc, clay, etc., and any of them are suitable. To produce the composition of the present invention, 180 to 2
A rubber softener heated and melted at 00°C and SEBS rubber are stirred and mixed in a predetermined ratio using a high shear stirring device such as a homomixer, and after the SEBS rubber is completely dissolved, the filler is added and mixed uniformly. The mixture is molded into a predetermined shape, and may be poured into a mold or molded using an extruder. Mixing can also be carried out using a Banbury mixer or a pressure kneader. [Example 1 Next, an example will be explained. Example 1 SEBS rubber (manufactured by Shell Chemical Co., Ltd., Kraton G1650
)1.5kg. Process oil (manufactured by Kyodo Oil Co., Ltd., Sonic Process Oil K. Homo mixer HV-SL (
Stir and mix at maximum capacity 20I2), and after 60 minutes, SEBS
After confirming that the rubber was completely dissolved, 3 kg of calcium carbonate was added and stirring was continued for an additional 10 minutes to obtain a homogeneous mixture. The softening point of this mixture is 102°C, and the viscosity at 200°C is 2100 CPS. Peel adhesive strength according to JISK6854 (adhesive peel adhesive strength test method) is 0.62k
gf/cm. Furthermore, in order to check the sealing performance when water pressure is applied, water pressure was applied to the adhesive surface of the sealant according to the waterproofing test method in the waterproof layer design and construction materials for road bridge reinforced concrete deck slabs (Japan Road Association). A test specimen was created at a test temperature of 20℃ and a water pressure of 3kgf/cm.
A test was conducted with a pressurization time of 60 minutes to check for water leakage. In this example, there was no water leakage at all. Example 2 2.5 kg of SEBS rubber and 7.5 kg of process oil were stirred and mixed in the same manner as in Example 1, and further 2 kg of talc was added.
was added and mixed to obtain a homogeneous mixture. The performance of this mixture is shown in Table 1. Example 3 SEBS rubber 2.5 kg. 7.5 kg of process oil was stirred and mixed in the same manner as in Example 1 to obtain a homogeneous mixture. The performance of this mixture is shown in Table 1. Example 4 Asphalt was preheated to 200°C at a ratio of 2.5 kg of SEBS rubber and 7.5 kg of straight asphalt with a needle size of 150 to 200 (manufactured by Mitsubishi Oil Corporation).
T. K. The mixture was stirred and mixed using a homomixer HV-SL, and after 60 minutes, 1 kg of calcium carbonate was added while confirming that the SEBS rubber had completely dissolved, and the mixture was further stirred for 10 minutes to obtain a homogeneous mixture. The performance of this mixture is shown in Table 1. Example 5 2.5 kg of SEBS rubber, 3.5 kg of process oil as a rubber softener, 2 kg of straight asphalt with a penetration of 100 to 120 (manufactured by Mitsubishi Oil Corporation), and 2 kg of turpentine liquid resin (Guimaron, manufactured by Yasushi Oil Co., Ltd.) were used. These rubber softeners were preheated to 180° C., stirred and mixed in the same manner as in Example 1, and 3 kg of talc was added and mixed to obtain a homogeneous mixture. The performance of this mixture is shown in Table 1. Example 6 3 kg of SEBS rubber and 7 kg of process oil were added to Example 1.
Stir and mix in the same manner as above, and add 4 kg of calcium carbonate.
was added and mixed to obtain a homogeneous mixture. The performance of this mixture is shown in Table 1. Comparative example 1
~3 As shown in the formulation column of Table 1, the amounts of SEBS rubber, process oil, and filler were set to values outside the scope of the present invention, and homogeneous mixtures were prepared in the same manner as in Example 1. did. The performance of each mixture is shown in Table 1. Comparative Example 4 This is a conventional molded seal material using butyl rubber. As mentioned above, the mixing ratio of SEBS rubber and rubber softener
If the EBS rubber is reduced to 15% by weight, the softening point of the composition will be 100° C. or lower, which is undesirable in practical use because there is a fear that sagging may occur under the influence of direct sunlight.

In addition, if the SEBS rubber exceeds 30% by weight, the viscosity of the composition when melted will be extremely high, and the viscosity at 20'O ℃ will be more than sooocps, which may cause problems especially in injection work. , Water leakage occurs due to poor sealing properties when water pressure is applied, making it unsuitable. Furthermore, if the blending ratio of SEBS rubber and rubber softener is appropriate, and if a filler is blended, the amount exceeds 40 parts by weight based on 100 parts by weight of the total amount of rubber and rubber softener, The peel adhesion strength was less than 0.4 kgf/cm, and water leakage was observed due to the sealing properties when water pressure was applied, which is undesirable. As is well known, the conventional butyl rubber rubber used in Comparative Example 4 has poor weather resistance, which not only limits the areas in which it can be used, but also has an extremely high viscosity, so it cannot be used as a heat-melting type. Even as a molded sealant, it has the disadvantage that it tends to leak when water pressure is applied. [Effect of the invention]

Claims (1)

[Claims] 1. 15 to 30% by weight of SEBS rubber, which is a block copolymer having a polystyrene phase as both terminal phases and a hydrogenated polyolefin phase as a rubber intermediate phase, and a rubber softener 7
An elastic sealing material composition characterized by using a mixture consisting of 0 to 85% by weight. 2. The rubber softener is at least one of process oil, straight asphalt with a penetration of 100 or more, and liquid resin.
The elastic sealing material composition according to claim 1, comprising: