JPH026578A - Self-fusing pressure-sensitive adhesive tape - Google Patents

Abstract

PURPOSE:To obtain the title tape improved in parting from calender rolls, heat resistance, etc., and prevented from undergoing telescopic side sticking by coating a plastic film support with a pressure-sensitive rubber adhesive layer comprising a mixture of an uncrosslinked rubber with a crosslinked rubber. CONSTITUTION:A mixture is obtained from 100 pts.wt. uncrosslinked rubber such as natural rubber or butyl rubber, 5-100 pts.wt. crosslinked rubber such as, desirably, butyl rubber and, optionally, about 20-100 pts.wt. softener such as a process oil and about 40-300 pts.wt. filler such as white carbon. A plastic film support such as a PE film of a thickness of about 0.05-0.25mm is coated with said mixture as a pressure-sensitive rubber adhesive layer in a coating thickness of about 0.1-3mm. It is preferable that said butyl rubber has a gel fraction of about 40-90% and that said filler has a particle diameter of about 5nm-20mum.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses a plastic film as a support, and is characterized in that 100 parts by weight of uncrosslinked rubber (hereinafter simply referred to as "parts") and 5 to 100 parts of crosslinked rubber are blended therein. This relates to adhesive tape.

By stretching self-adhesive tape and wrapping it around iron pipes, cables, etc., the tape's weight lines (occurring grooves) are completely clogged, filling the minute irregularities on the surface of the material and preventing the passage of moisture on the surface layer. In order to eliminate corrosion, it is used as anti-corrosion tape, insulating tape, etc., which is far superior to pressure-sensitive tape, and its uses are gradually expanding.

The self-adhesive tape that is commonly used is a polyethylene film coated with uncrosslinked rubber thicker than the film, and by stretching and wrapping it, it achieves the purpose of corrosion protection and insulation, but only uncrosslinked rubber coats it. is used, it lacks heat resistance, is easily exposed to cytostick telescopes, etc., and there are also problems with the adhesive strength between the film and the rubber adhesive layer. JP-A-59-i60908 describes an insulating tape using crosslinked rubber and uncrosslinked rubber.

This tape consists of 80 to 120 parts of crosslinked rubber and 3 parts of uncrosslinked rubber.
It is characterized by a high blending ratio of frame rubber, ranging from 0 to 70 parts. When the blending ratio of cross-linked rubber is high, the calender separation tends to be poor due to the tendency of boat fishing, which tends to cause roughness on the adhesive surface, and the unwinding force is large because the adhesion to the film surface is too strong. There is a drawback that the part becomes difficult to peel off, making this part unusable.

On the other hand, the tape of the present application uses an appropriate proportion of uncrosslinked rubber and crosslinked rubber, so it is easy to manufacture and has good calender release, so the adhesive surface is smooth and can be rolled even after a long period of time. There is little change in adhesive strength from the beginning to the end of winding, and it has excellent heat resistance, and is resistant to telescope and sight stick. The present invention will be described in detail below.

The plastic film of the present invention is a film of easily stretchable thermoplastic plastic such as polyethylene, polypropylene, flexible polyvinyl chloride, etc., and its thickness ranges from 0.05 to 0.25 mm. The most preferred is a soft polyvinyl chloride film, which stretches uniformly against increases in stress and is therefore easy to wind at a constant stretching rate (it is flame retardant, has excellent strength, and has good weather resistance). Usually, a film containing 100 parts of polyvinyl chloride resin and 60 to 130 parts of a plasticizer is used.

The present invention is characterized by blending 5 to 100 parts of crosslinked rubber with 100 parts of uncrosslinked rubber, and is characterized by good heat resistance, good calender release, and easy production. A preferable range is 10 to 50 parts of crosslinked rubber per 100 parts of uncrosslinked rubber. The thickness of the rubber layer is usually <0.1 to 3 times thicker than the film.

Rubbers used as uncrosslinked rubber and crosslinked rubber include natural rubber,
Examples include butyl rubber, phtadiene-styrene rubber, ethylene propylene rubber and urethane rubber, but butyl rubber is preferred because it has excellent aging resistance. In the present invention, the crosslinked rubber may be any crosslinked rubber, but preferred is a crosslinked butyl rubber with a gel fraction usually in the range of 40 to 90%.

In the present invention, 5 to 200 parts of a softener are used per 100 parts of uncrosslinked rubber. The softening agent used is process oil, polybutene, plastic paraffin, fats and oils, coal tar, etc., and the preferable range is 20 to 100 parts. When a soft vinyl chloride film is used, 10 to 50 parts of plasticizer is used per 100 parts of uncrosslinked rubber to prevent migration of the plasticizer in the film.

In the present invention, 40 to 300 parts of filler is added to 100 parts of uncrosslinked rubber.
Use part. The filler used is white carbon, carbon black, clay silica, Merck, calcium carbonate, etc., and the preferable range is 25 to 100 parts, and the preferable filler is white carbon and carbon black with small particles. The preferred particle size range is 5 mμ to 20μ.

The following method is used to knead crosslinked rubber with uncrosslinked rubber to create a uniform adhesive layer with a clean adhesive surface. Crosslinked rubber has a higher viscosity than uncrosslinked rubber, so it is difficult to mix. Therefore, in order to lower the viscosity of crosslinked rubber, it is thinly rolled using a roll or the like to bring it closer to the viscosity of uncrosslinked rubber. However, if the crosslinked rubber has a Kel fraction of 40% or more, the viscosity does not decrease easily, so the particle size is small, and the preferable particle size is 10 mμ to 1.00 mμ.
White carbon and carbon black having a diameter of 0 mμ are used.

If the rubber mixture is not uniformly coated, the adhesive surface will have an uneven surface, resulting in a decrease in adhesive strength, variations in unwinding force, telescoping, etc. - To give an example, crosslinked rubber is rolled with a gap of about 1 - and a roll temperature of 20 to 60C.
Perform thin threading 10 times. Next, the mixture is kneaded together with the uncrosslinked rubber in a pressurized kneading machine at a temperature of about 145C for 5 minutes, a filler and a softener Φ are added, and the mixture is kneaded at the same temperature for 15 minutes to form an adhesive.

Adding a large amount of fine particle filler such as carbon black or white carbon will lower Mooney viscosity, but will also reduce flow and help prevent side snacking and telescoping.

Topping of the adhesive onto the plastic film is usually done using a calender roll. When using a three-roll calender, the roll temperature is 50 to 140 C for the upper roll.
, middle roll 50~110C1 lower roll 5~60tl
The adhesive can be easily manufactured using rolls, kneaders, etc.
It is heated in advance to 90 to 130C by a method such as the above method, and then supplied to a calender. The temperature of the upper roll is 50C
If it is less than 140C, the film cannot be transferred to the medium roll, and if it is more than 140C, the film will stretch or wrinkle.

If the temperature of the middle roll is lower than 50 tl', the adhesive will separate from the roll; if it is higher than <<110 tl', the film will stretch or wrinkle.

The film stretches when the bottom roll is over 6 Or. Tapes manufactured in this way have a uniform adhesive layer and a smooth surface, and there is little variation in adhesive strength, and the unwinding force is constant from the beginning to the end of the winding. It has certain characteristics. When a four-roll calender is used, it is preferable that the rotation of the side roll is slower than that of the upper roll and the temperature thereof is about 10 C higher than that of the upper roll, and the other rolls may be kept under the same conditions as the three-roll calender.

Next, embodiments of the present invention will be described.

Example 1 100 parts of a polyvinyl chloride resin with an average degree of polymerization of 1.100, 45 parts of dioctyl phthalate, 22 parts of a filler, and 4 parts of a stabilizer were uniformly kneaded and rolled in a calender to obtain a 0.171a
No. 11 film was used. Cross-linked butyl rubber (gel fraction 80
%) The Mooney viscosity of uncrosslinked butyl rubber (
1ooCML1+a) The Mooney viscosity was set to 48, which is close to 45. Next, add particle size 2 to uncrosslinked butyl rubber at the blending ratio shown in Table 1.
Add 5 mμ of carbon black and mix with a pressure kneader.
After kneading at 45C for 5 minutes, white carbon having a clay particle size of 15 mμ, dioctyl phthalate, polybutene, and terpene resin were added and kneaded for 15 minutes. The resulting adhesive was uniform and had appropriate properties. Using the above vinyl chloride film and adhesive, the upper roll, middle roll, and lower roll were heated to 12 Or each using a three-roll calender.

Topped with 90r and 20c. Glue thickness is 0.53
m, but the release of the adhesive from the calendar was extremely good.
A tape with a smooth adhesive surface and good adhesiveness was obtained.

Example 2゜Example 1. The tape obtained in step 1 was wrapped around a water pipe with a 1/2 lug, both ends of which were sealed, and the tape was placed in water and immersed for 3 months. When the iron pipe was removed and the tape was untied, the water flow had completely stopped and the irregularities on the surface were covered, and no rust was observed at all, and there was no evidence of water entering the pipe.

Example 6゜Example 1. The resulting tape was tested in comparison with a commercially available polyvinyl chloride self-bonding tape.

The results were as follows.

(1) Telescope The tape of the present invention and a commercially available polyvinyl chloride self-fusing tape were heated at 4011' for 48 hours.

The tape of the present invention showed no telescope, whereas the commercially available product showed five cabinets of telescope.

(2) Take samples from the surface layer, middle layer, and core layer of two types of tapes with unwinding force.
The unwinding force was measured at a speed of 00 M/min.

The results were as follows.

Tape of this application Commercially available tape surface layer 1.024/25m 1.21Kg/25m
Layer 1.10Kf/258 1.55KF/25mm
Core layer 1.05Kf/259 2.15 glaze/2511
Im results showed that the tape of the present application showed a fairly uniform unwinding force from the beginning to the end, whereas the commercially available tape became extremely heavy as it approached the window, and the part in contact with the core had almost no unwinding force. It was something that would never happen.

(3) Self-back adhesive strength The self-back adhesive strength of two types of tapes was measured and the results were as follows.

Tape of the present application Commercially available tape Surface layer 1.00 instant/25cm 0.85 instant/25■ middle layer
1.05 to 9/25■ 1.10 immediately/25 core part layer
1.05Kg/25■ 1.84Kg/25m In this way, the tape of this application has almost uniform adhesive strength in the surface layer, middle layer, and core layer, whereas commercially available tapes have large variations in adhesive strength depending on the location. there were.

Claims (1)

[Claims] Consisting of a plastic film and a rubber adhesive layer, the rubber adhesive layer contains 100 parts by weight of uncrosslinked rubber and 5 to 100 parts by weight of crosslinked rubber.
Self-adhesive tape characterized by containing parts by weight