JPS6025728A - Heat-shrinkable sheet for t-pipe - Google Patents

Abstract

PURPOSE:To obviate the displacement or the like when shrinking is effected by heating, by providing a sheet section that has an aperture section at a position corresponding to a neck section of a rising section of a branch pipe and a shape to cover a main pipe, the undersurface of the part around the aperture section having an adhesive layer that exhibits a high shear strength at high temperatures. CONSTITUTION:A heat-shrinkable sheet 1 has a sheet section 11 having an aperture section 12 at a position corresponding to a neck section 22 of a rising section of a branch pipe 21 and a shape capable of covering all the circumference of the main pipe 23, and the undersurface of the sheet section 11 has an adhesive layer 14 that exhibits a high shear strength at high temperature. The heat- shrinkable sheet 1 is put around the circumference of the main pipe 23 with the opposite sides of the sheet 1 overlapped and connected by a heat seal tape 3 and is heated to be shrunk. The part where the adhesive layer 14 is situated would not be displaced when the sheet 1 is heated and shrunk.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat-shrinkable sheet for a T-tube having a specific adhesive layer suitable for covering a T-tube.

Conventionally, the shape of pipes in heavy chemical factory plants, pipes for urban central heating, or pipes around pump stations for crude oil and natural gas transportation pipelines have been shaped like elbows,
There are a wide variety of products such as reducers, valves, T-shaped pipes, flange parts, etc., but when conventional heat-shrinkable sheathing materials are applied to these irregularly shaped pipes, the heat-shrinkable sheathing material will In addition to shrinking in the circumferential direction, for example, a considerable "shift" in the width direction of the coating material, which is perpendicular to the direction of heat shrinkage (the circumferential direction of the tube), may occur due to dimensional changes during heat shrinkage. As a result, the coating material sometimes slips off the surface of the portion of the irregularly shaped tube to be coated, peels off, or forms a void.

That is, if the irregularly shaped pipe to be coated is a T-shaped pipe with branch pipes branching from the main pipe in a ``■'' shape, a heat shrinkable jacket with a large heat shrinkage rate is used. When it is wrapped around the pipe and heat-shrinked, during the heat-shrinking, the covering material is tightly attached around the main pipe and branch pipe by heat shrinking in the circumferential direction (the width of the covering material There is also a large contraction in the direction, and the rising part of the bamboo branch pipe shifts away from the neck and the surrounding part of the main pipe, and it comes off from the neck of the pipe to be covered and its surroundings. There was a problem.

The present inventors have discovered that the heat shrinkability (corrosion prevention) of the above-mentioned single-shaped tube
As a result of intensive research into solving the problems that coating materials had, we developed a new adhesive layer that maintains a high shear strength, which is related to adhesive strength, even at high temperatures where the coating material shrinks due to heat. It has been found that by employing a heat-adhesive adhesive layer containing an elastomer material as a main component, problems such as shearing of heat-shrinkable coating materials caused by heat-shrinking can be solved.

The present invention was made based on the above findings, and is a heat-shrinkable sheath I for covering an F-shaped pipe having a T-shaped branch pipe branching from a main pipe. The part corresponding to the neck of the rising part of the branch pipe of the pipe is opened or cut out, and has a shape that can cover part or the entire circumference of the main pipe of the single-shaped pipe, and the back part is The present invention provides a heat-shrinkable sheet for a T-shaped tube, characterized in that an adhesive layer exhibiting high shear strength at high temperatures is provided at least in a portion including the peripheral edge of the opening or cutout.

When the heat-shrinkable sheet for a T-shaped pipe of the present invention is placed around the main pipe of an I'-shaped pipe and subjected to heat shrinkage, the adhesive layer on the back side has high shear strength at the heat shrinkage temperature. Because of this, it is tightly attached to a part of the main pipe around the neck of the branch pipe during heat shrinkage, and there is almost no problem of it shifting in the width direction or peeling off at high temperatures.

Hereinafter, embodiments of the heat-shrinkable sheath I for T-shaped pipes of the present invention will be described in more detail with reference to the drawings.

FIG. 1 shows a perspective view from the back side of an embodiment of the heat-shrinkable sheet for 'I'-shaped pipes of the present invention. The heat-shrinkable sheet 1 is provided with an opening 12 at a location corresponding to the neck 22 of the rising portion of the branch pipe 21 of the 'I'-shaped tube 2 as shown in FIG. A sheet portion 11 having a shape capable of covering the entire circumference of the main pipe 23; and the sheet portion]1
An adhesive layer 14 that exhibits high shear strength at high temperatures is provided on the entire back surface area of the holder.

The sheet portion 11 is a cross-linked plastic film or sheet having heat-shrinkable properties known in the art, or a cross-linked brass film formed from a laminated sheet thereof.
It's fine if it's just a joke.

The sheet portion 11 of the present invention formed of this crosslinked plastic film or sheet 1- has a heat shrinkage temperature of about 8
It is sufficient that the temperature is about 0 to 200°C, especially about 90 to 180°C, and the heat shrinkage rate is about 20 to 80%, especially about 30 to 70%. It is preferable that the degree is about 20 to 90%, particularly 25 to 80%, expressed as the gel fraction described below.

The above gel fraction refers to the sample (cross-linked plastic film or sheet) that is dissolved in xylene by placing it in xylene and dissolving it under reflux at a temperature of about 130°C for about 10 hours. The value obtained by dividing the weight (Ag) by the weight (Bg) of all the samples used is multiplied by 100.

Gel fraction - (A/B) vinyl,
Polyester, polyamide (nylon-6, nylon-
6,6) and other thermoplastic resins by extrusion molding, etc.
After forming into a film or sheet, it is exposed to electron beams, X-rays,
A crosslinked film or sheet is formed by irradiation with radiation such as gamma rays or by chemical reaction with a suitable peroxide, etc., and then the firn or sheet is made into a crosslinked film or sheet.
It is suitable if it is formed from a heat-shrinkable crosslinked plastic film obtained by stretching at a high temperature of 0 to 200°C and cooling in the stretched state, or from C.I.

In the present invention, ζ, the adhesive layer 14 is the heat-shrinkable sheet portion (or the heat-shrinkable crosslinked plastic layer>1
1 exhibits the largest heat shrinkage force (e.g., also referred to as heat shrinkage temperature; high temperature in the range of about 80 to 200°C), the heat shrinkage force is within the range of about 0:002 to 0.05 kg/cJ, preferably 0. It exhibits an adhesive strength expressed by a shear strength <AsTMD 1002> within the range of 0.005 to 0.04 kg/cJ, and the shear strength does not drop immediately and rapidly even if the temperature is raised further than the heat shrinkage temperature. , consisting of an adhesive layer containing an elastomer material as a main component.

This adhesive layer I4 maintains adhesive strength at high temperatures as described above, and at cold temperatures (near about 20"C),
About 0.8-30 kg/cJ, especially 1. O~3Qkg
, /cjA is suitable.

The adhesive layer 14 may be made of an olefin elastomer such as polyisobutene rubber (IIRi butyl rubber), ethylene-propylene copolymer rubber (EPR), or ethylene-propylene-nonconjugated diene copolymer rubber (EPDM). , polybutadiene rubber, polyisoprene rubber,
Other non-conjugated diene elastomers such as styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, chloroprene rubber, chlorosulfonated polyethylene rubber, acrylic rubber, epichlorohydrin rubber, chlorinated polyethylene rubber, fluorinated rubber, etc. The elastomer component is about 30 to 70% by weight, especially 35 to 6% by weight.
The content is preferably 5% by weight.

In addition to the elastomer component, the adhesive layer 14 also contains other modifying polymers (
Modifying polymers), adhesive agents, corrosion inhibitors, and inorganic fillers may also be blended. Examples of the modifying polymers include polyethylene, ethylene-vinyl acetate co-merged, Examples include olefin polymers such as ethylene-propylene copolymer, acrylate-ethylene copolymer, polypropylene, and polybutene, as well as thermoplastic resins or liquid polymers such as polyvinyl chloride, polyamide, and styrene polymers. , Adhesive agents include rosin and rosin derivatives, pinene resins, aliphatic hydrocarbon resins (Cs fraction, pentene,
(single or copolymers of isoprene, 1,3-pentadiene, etc.), aromatic hydrocarbon resins (single or copolymers of C9 fraction, styrenes, indenes, etc.), alicyclic hydrocarbon resins, coumaron resins 1 , coumaron-indene resin,
Examples include phenolic resins, naphthenic oils, and modified terpenes. Examples of corrosion inhibitors include inorganic corrosion inhibitors such as metal chromates, metal phosphates, metal phosphites, metal borates, molybdates, and metal nitrites, aromatic carbon Examples include metal salts of acids, aliphatic or aromatic compounds having multiple hydroxyl groups, organic corrosion inhibitors such as tannic acid, and inorganic fillers such as talc, carbonaceous, silica, alumina, and mica. , carbon black, etc.

In the present invention, the adhesive layer 14 includes about 30 to 70% by weight of the above-mentioned olefin elastomer, about 1 to 20% by weight of the modifying polymer, about 10 to 30% by weight of the adhesive agent,
A heat-adhesive adhesive composition containing about 0 to 20% by weight of an inorganic filler has an adhesive strength (shear strength) of about 1.0 kg/cJ or more at room temperature, and has a high adhesive strength at high temperatures. Adhesive strength (shear strength) is approximately 0.0 at 80°C. Ol kg
/cJ or more, approximately 0.005kg/cII at 100℃!
It is optimal because it is as high as 2.

In the heat-shrinkable sheet 1 for T-shaped pipes of the present invention, if the elastomer component of the adhesive [14] becomes too small, the heat-shrinkage temperature of the heat-shrinkable coating material will be approximately At temperatures above 80°C, the shear strength of the adhesive becomes extremely small or rapidly decreases, so it is not suitable. Also, if the elastomer component is too large, the adhesive strength after cooling to room temperature becomes small, so it is not suitable. isn't it.

Note that tackifiers are blended with the main purpose of imparting fluidity (=Js1) and tackiness to the adhesive, and if the amount of Q is too low, these properties will be lost. Undesirable.

The heat-shrinkable sheet 1-1 for a T-shaped tube of the present invention is such that the adhesive layer 14 having high shear strength at high temperatures is provided on the entire back surface area of the heat-shrinkable sheet portion 11. Preferably, if necessary, as shown in FIG. 2, the portion of the heat-shrinkable sheet portion 11 that contacts the neck of the branch pipe of the T-tube, including the periphery of the opening 12, is provided with high shear strength at high temperatures. The adhesive layer 14 having the above-mentioned adhesive layer 14 may be provided, and an ordinary bot-melt type adhesive layer 15 may be provided on the other back surface portion.

Typical bot-melt type adhesive layer 15 is made of thermoplastic resin such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, acrylonitrile-ethylene copolymer, polyvinyl chloride, polyester, polyamide, etc. % by weight, asphalt (bitumen) 0-50% by weight, tackifier 10-20% by weight,
E7) A melt-type adhesive containing 5 to 20% by weight of an inorganic filler has excellent adhesive strength (shear strength of 5 to 30 kg/cIil) at product temperature,
Moreover, it is suitable because it can be applied to small irregularities and rough surfaces on the surface to be coated by heating, softening and flowing.

Further, in the present invention, the opening 1 provided in the seat portion 11
2 can penetrate the branch pipe 21 of the i'-shaped bamboo 2 when covering the main pipe 23 of the T-shaped pipe 2 with the heat-shrinkable sheet 1 for single-shaped pipes of the present invention, and Seat part 11 by heating
It is sufficient that the heat-shrinkable sheet 1 for a double-shaped tube of the present invention is provided in a form that allows it to be in close contact with the main pipe 23 around the neck 22 of the branch pipe 21 of the double-shaped tube 2 during heat shrinkage. teeth,
As shown in FIG. 3, the cutout 13.13 replaces the opening 12
The seat portion 11 may have the following.

In addition, in the present invention, the size of the seat portion 11, particularly its length, is not necessarily limited to T as shown in FIGS. 1 to 3.
It does not have to be large enough to cover the entire circumference of the main pipe 23 of the double-shaped pipe 2, but it is large enough to cover the main pipe 23 around the neck 22 of '1゛1°2, as shown in Fig. 7. As shown in Fig. 1 or Fig. 8, it is composed of a pair of sheets 1' and 1°.
The heat-shrinkable sheet 1 for an R-shaped pipe of the present invention has an adhesive layer 14 that exhibits high shear strength at high temperatures as described above over the entire back surface area.

Further, the heat-shrinkable sheet 1-1 for a T-shaped tube of the present invention does not necessarily have to be a rectangular sheet as shown in FIGS. 1, 2, 3, and 7. The shape may be any shape as long as it is compatible with the surface of the main pipe 23, and may be, for example, trapezoidal, fan-shaped, or other shapes.

In addition, in FIG. 1, FIG. 2, FIG. 3, FIG. 7, and FIG.
is the direction of heat contraction.

Next, the heat-shrinkable sheet 1 for a single-shaped pipe of the present invention shown in FIG.
The following describes the embodiment of the jointed T-shaped pipe 2, which is carried out using the above together with another heat-shrinkable seam 1-, according to a preferred construction order.

For the above-mentioned covering, first, as shown in FIG. The parts are overlapped, and the overlapped parts are connected with a heat seal tape 3 to form a cylinder, and then the heat-shrinkable sheet 1 for a single-shaped tube, which has been formed into a cylinder, is heated with the flame of a gas burner to be heat-shrinked. The heat-shrinkable sheet for T-shaped pipes 1 is bonded to the main pipe 23 with an adhesive layer 14 exhibiting high shear strength at high temperatures by further heating and bonding it to the main pipe 23 as shown in FIG. Cover. With this construction, when the conventionally known heat-shrinkable coating material is heated, the neck portion 2 of the single-shaped pipe 2
However, according to the heat-shrinkable sheet 1 for 1° 1° of the present invention, the adhesive layer 14 having high shear strength at high temperatures ,
Unlike conventional heat-shrinkable sheets, it does not shift during heat-shrinking.

Next, a heat-shrinkable sheet 4 for a branch pipe with an adhesive layer as shown in FIG. The parts are overlapped and the overlapped parts are connected with a heat seal tape 5 to form a cylindrical shape as shown in FIG. The heat-shrinkable sheet 4 for the branch pipe is bonded tightly to the surface of the branch pipe 21 while being heated and heat-shrinked.
It is connected to the branch pipe 21 and covered as shown in FIG.

In addition, at the time of this joining, a part of the heat-shrinkable sheet 4 for the branch pipe and a part of the heat-shrinkable sheet 1 for the T-shaped pipe of the present invention, which has already been joined to the main pipe 23 as described above, are connected to the T-shaped pipe. The cylindrical bodies of heat-shrinkable sheets 4 are arranged so as to overlap at the neck 22 of the tube 2.

In addition, when the branch pipe 21 of the spot-jointed T-shaped pipe 2 to which the branch pipe 21 is applied has a small diameter as shown in FIG. 4, it is preferable to use a heat-shrinkable sheet 4 for the branch pipe having a shape as shown in FIG. As the adhesive layer, it is preferable to use an adhesive layer that exhibits high shear strength at high temperatures as described above. In addition, the heat shrinkable sheet 4 for branch pipes is 20 to 70% preferably 30 to 70%
It is preferable to form it into a cylindrical shape so that it will come into close contact with the branch pipe 21 when it is thermally shrunk by 60%.

In addition, when covering the T-shaped pipe 2, the construction order is not limited to the above-mentioned construction order. For example, covering the branch pipe 21 with the heat-shrinkable sheet 4 for the branch pipe, and covering the main pipe 23 with the heat-shrinkable sheet 4 for the T-shaped pipe It may be carried out prior to coating the sheet 1.

Further, when the branch pipe 21 of the potato-jointed T-shaped pipe 2 has a medium or large diameter, it is preferable to use a heat-shrinkable sheet 4'' for a rectangular branch pipe as shown in FIG.

In this case, the heat-shrinkable sheet 4” for the branch pipe is 20 to 70%
Preferably, it is formed into a cylindrical shape so that it comes into close contact with the branch pipe 21 when it is thermally shrunk by 30 to 60%.

Further, the heat-shrinkable sheet 1 for single-shaped pipes of the present invention having the shape shown in FIG. 1 is particularly suitable for covering the above-mentioned R-shaped pipe 2.

As described above, the first tube sufficient to cover the entire circumference of the main pipe 23 of the T-shaped pipe
The method for covering a 1'-shaped tube using the heat-shrinkable sheet 1 for I'-shaped tubes of the present invention having the shape as shown in the figure has been described. When covering the entire circumference of the main pipe 23 using the heat-shrinkable sheet 1'' for single-shaped pipes of the present invention, which does not have
As shown in Figure 9, the heat-shrinkable sheet for T-tube (-1
After placing it on a part of the main pipe 23 around the neck 22 of the 'R-shaped tube 2, a sheet with a known adhesive layer is placed so as to partially overlap the heat-shrinkable sheet 1-1° for the 'R-shaped tube'. A heat-shrinkable sheet 6 is placed around the remaining entire circumference of the main pipe 23, and the overlapping portion with the heat-shrinkable sheet 1 for the T-tube is joined with a heat seal tape 3. Shrinkable sheet 1
The heat-shrinkable sheet 6 with adhesive may be thermally bonded to the main pipe 23 while being heated and heat-shrinked.

Below, we will compare test examples of the adhesive forming the adhesive layer of the heat-shrinkable sheet for single-shaped pipes of the present invention and examples of coating methods using the heat-shrinkable sheet for single-shaped pipes of the present invention. Shown together with test examples and comparative examples.

In addition, in the test examples and comparative test examples, the shear strength of the adhesive was determined by overlapping two iron plates (125 mm x 25 mm x 1.5 mm) 12 times over each other and interposing an adhesive in the overlapping part. Approximately 5 to 130”c junction temperature
The iron plates were heated for 1 minute, joined together, and then simultaneously pulled in the direction of both ends using a universal testing machine, and measured according to the measurement method of STM D1002.

Test Example 1 An adhesive having the composition shown below was cross-wired at a temperature of 150° C. for 5 minutes using a knee gun, and then an adhesive sheet having a thickness of 1.5 mm was bound using a roll.

Butyl rubber 25% by weight Ethylene-propylene-non-conjugated diene copolymer 30% by weight Polybutene 5% by weight Coumaron-indene resin 20% by weight Kuruku 10% by weight This adhesive sheet was measured using the shear strength measurement method described above. It is 0.014 kg/cta at 105°C, 0.029 kg/cta at 80°C, and 1 at 20°C.
, 15 kg/cta.

Comparative Test Example An adhesive sheet (comparative adhesive) was formed in the same manner as Test Example 1, except that the composition of the adhesive was changed as follows.

20% by weight of ethylene-propylene-non-conjugated diene copolymer 25% by weight of ethylene-ethyl acrylate copolymer 45% by weight of coumaron-indene wfJ 45% by weight of micro wax 10% by weight This adhesive sheet was measured using the shear strength measurement method described above. As a result, the shear strength was 0.001 kgloJ at 105°C and 0.124 kg/cn at 80°C, and the shear strength decreased to a very small extent around 110°C, and further at 20°C.
It was 24.2 kg/cal.

fruit. Example The adhesive sheet obtained in the above test example was applied to one side of a crosslinked plastic sheet (thickness 1.0 female, gel fraction 60%, heat shrinkage rate in the length direction 45%, heat shrinkage temperature 105°C). A heat-shrinkable sheet of the present invention having a shape as shown in FIG. ) was formed.

This heat-shrinkable sheet was then attached to a jointed T-tube (main pipe outer diameter: 800 mm, branch pipe outer diameter: 300 mm), as shown in Figure 4.
Wrap it around a main pipe of mm) and join both ends with heat seal tape to form a cylinder, and heat the knot-shaped coating material to about 105 to 110 ° C with the flame of a gas burner.
The sheet was heat-shrinked to fit tightly around the main pipe, and heating was continued to bond the heat-shrinkable sheet around the main pipe using the adhesive layer. Next, another heat-shrinkable sheet having a shape as shown in Fig. 5 (heat shrinkage rate: 40%, thickness: 'l, 5 long, width: 700 long, length, J, wasted from a 600-long square sheet) (The adhesive layer sheet obtained in the comparative test example above was used as the adhesive layer.) In a manner not shown in Fig. 4, the adhesive layer was cut out to a minimum, and the adhesive layer sheet obtained in the comparative test example was used in the same manner as the main pipe coating described above. to cover the branch pipes.

As a result, the heat-shrinkable sheet 1- and other heat-shrinkable sheets of the present invention do not cause "slippage" in the vicinity of the neck of the rising portion of the branch pipe of the T-shaped pipe, and provide good coverage as shown in FIG. formed a layer.

Comparative Example Instead of the heat-shrinkable sheet 1- of the present invention used in the above example, a heat-shrinkable sheet (comparative In Example 1, a T-tube was covered in exactly the same manner as in the above Example using the sheet.

As a result, when covering the main pipe, approximately 10% of the above comparison sheet was used.
When heated to 5°C or higher, the comparison product causes a significant "slippage" in the wood pipe area around the neck of the rising part of the branch pipe of the T-tube, and this r-slip causes the branch pipe to undergo separate heat shrinkage. The damage further increased due to heating during covering with the plastic sheet, and a wide area around the neck was exposed.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of one embodiment of the present invention from the back side;
The figure is a perspective view from the back side of another embodiment of the present invention, FIG. 3 is a perspective view from the back side of yet another embodiment of the present invention, and FIG. 4 is a main view of one embodiment of the present invention. FIG. 5 is a plan view showing an example of a heat-shrinkable sheet with an adhesive layer for a branch pipe used in conjunction with an embodiment of the present invention when covering an I"-shaped pipe; FIG. FIG. 6 is a perspective view showing an embodiment of the present invention connected to a main pipe, FIGS. 7 and 8 are plan views of another embodiment and still another embodiment of the present invention, and FIG. The figure is a perspective view showing how the main pipe is covered in the embodiment shown in Fig. 7, and Fig. 10 is a plan view showing another example of a heat-shrinkable sheet with an adhesive layer for branch pipes. ” Heat-shrinkable sheet for T-tube 11 Sheet portion 12 Opening portion 13 Cutting portion 14 Adhesive layer 2 exhibiting high shear strength at high temperatures...
T-shaped pipe 21...Branch pipe 22...Neck 23...Main bamboo Fig. 4 Fig. 5 Fig. 6 Fig. 1 Fig. 7 Fig. 8゜A

Claims (1)

[Claims] A heat-shrinkable sheet for covering a T-shaped pipe that has branch pipes that branch out from the main pipe in a T-shape, where the part corresponding to the neck of the rising part of the T-shaped pipe is opened or cut out. It has a shape that can cover part or the entire circumference of the main pipe of the T-tube, and the back side part, at least the part including the peripheral edge of the opening or cut part, is heated to a high temperature. A heat-shrinkable sheet for single-shaped pipes, characterized by being provided with an adhesive layer that exhibits high shear strength.