JPS6021234A - Thermal shrinkable covering material for specials - Google Patents

Abstract

PURPOSE:To prevent the slippage of a covering material from its thermal shrinkage for covering a specials by laminating a layer of thermal shrinkable bridged plastic with a layer of elastomer family adhesive having a specific adhesive strength. CONSTITUTION:To the inside of a layer of thermal shrinkable bridged plastic 2 which is made by elongating and cooling bridged plastic, a layer of adhesive 3 consisting of olefine family elastomer which shows adhesive strength (shearing strength) of 0.005-0.05kg/cm<2> at an area of high temperatures (80-200 deg.C) where said bridged plastic layer 2 shows the largest thermal shrinking strength is laminated, and the laminated material thus obtained is wrapped around a specially shaped pipe 4 such as a reducer, etc. and it is formed into a tubular shape by joining with a heat seal tape 6 and the pipe is covered with thermal shrinkable material by heating it with a gas burner. Generally speaking, a covering material 1 tends to slip down from a large diameter part 5' to a small diameter part 5 at the time of covering by thermal shrinkage, but this material is laminated with a layer of specific adhesive, therefore such a trouble is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat-shrinkable coating material having a specific adhesive layer suitable for coating the outer peripheral surface of various shaped tubes.

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 may slip off or peel off from the surface of the portion of the irregularly shaped tube to be coated, or a void may be created. In particular, the irregularly shaped pipe to be coated is
(The outer circumference length or outer diameter of the pipe gradually increases in one direction)
In the case of a reducer type with a small size, if a heat-shrinkable coating material with a large heat shrinkage rate is wrapped around the reducer to form a cylindrical body and heat-shrinked, the The coating material that adheres tightly around the reducer due to heat contraction in the circumferential direction also causes a large contraction in the width direction of the coating material, shifting toward the shorter outer circumference of the tube, causing damage to the tube to be coated. It becomes out of place.

As a result of intensive research into solving the problems that the heat-shrinkable (corrosion-proof) coating material had on the aforementioned irregularly shaped pipes, the inventors discovered that the adhesive layer could be used as an adhesive layer even at high temperatures when heat-shrinking. By adopting a heat-adhesive adhesive layer mainly composed of an elastomer material that can maintain a high value of shear strength related to adhesion, it is possible to eliminate the slippage that occurs when heat-shrinkable coating materials shrink. He discovered that this problem could be solved and completed this invention.

This invention includes a heat-shrinkable crosslinked plastic layer;
The adhesive layer on one side of the entire surface area of the coating material laminated with the heat-adhesive adhesive or the adhesive layer on a partial area of the coating material at high temperatures exhibiting the largest thermal shrinkage force of the coating material. Characterized by being formed of an adhesive based on an elastomeric material capable of exhibiting an adhesive strength expressed in terms of shear strength (ASTM 111002) in the range of about 0.005 to 0.05 kg/-. The present invention relates to heat-shrinkable coating materials.

The heat-shrinkable coating material of the present invention is placed around various irregularly shaped tubes to form a cylindrical shape, and when heat-shrinked, the adhesive layer has high shear strength at the heat-shrinkage temperature of the coating material. As a result, the coating material, which has been heat-shrinked and tightly adhered to the surface of the irregularly shaped tube, is unlikely to shift in the width direction or partially peel off at high temperatures.

Hereinafter, the heat-shrinkable coating material of the present invention will be explained in more detail with reference to the drawings.

FIG. 1 shows an example of the heat-shrinkable coating material of the present invention (
FIG. 1 is a side view and a top view of the mountain.

FIG. 2 is a perspective view showing an example of a situation in which the heat-shrinkable coating material of the present invention is wound around a deformed tube to be coated, and both ends of the tube are joined to form a cylindrical body.

FIG. 3 shows that a second
It is a perspective view which shows an example of the situation where the irregularly shaped pipe|tube similar to the figure is covered.

The heat-shrinkable coating material in this invention is roughly, for example,
As shown in FIG. 1, heat-shrinkable coating materials (sheets or tubes) 14 for various shaped pipes are laminated with heat-shrinkable cross-linked plastic N2 and a heat-adhesive specific adhesive layer 3. This is relevant.

The crosslinked plastic layer may be formed from a conventionally known heat-shrinkable crosslinked plastic film or sheet, or a laminated sheet thereof.

In this invention, the crosslinked plastic film or sheet has a heat shrinkage temperature of about 80-200°C, especially 90-200°C.
It is sufficient that the temperature is about 180°C and the heat shrinkage rate is about 2θ to 80%, especially about 30 to 70%.Furthermore, the degree of crosslinking of the polymer used to form the film or sheet is as follows: Expressed as a fraction, about 20-90%, especially 25%
It is preferable that it is 80%.

The above gel fraction refers to the sample (cross-linked plastic film or sheet) placed in xylene and dissolved under reflux at a temperature of about 130°C for about 10 hours, and the sample that did not dissolve in xylene. 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) After forming a thermoplastic resin such as nylon-6, nylon-6, 6) into a film or sheet by extrusion molding, it is irradiated with radiation such as electron beams, The heat obtained by chemically reacting with an oxide, etc. to form a crosslinked film or sheet, then stretching the film or sheet at a high temperature of about 80 to 200°C, and cooling it in the stretched state. It is suitable if it is formed from a crosslinked plastic film or sheet that has shrinkage properties.

In this invention, the adhesive layer is formed in a high temperature region (for example, about 80 to 200°C
(at high temperatures within the range of about 0.0 O5 to 0.05
kg/c barge, preferably 0, OO7~0.
04 Shear strength in the range of ktr/csl (^STM
D1002).
It consists of an adhesive layer whose main component is an elastomer material.

As mentioned above, the adhesive layer has adhesive strength (
At room temperature (around 20℃), the shear strength is approximately 0.8 to 30 kg/crA.
In particular, it is appropriate that it is about 1.0 to 30 kg/C11.

The adhesive layer may be made of, for example, polyisobutyne rubber (II
R; butyl rubber), olefin elastomers such as ethylene-propylene copolymer rubber (F, PR), ethylene-propylene-nonconjugated diene copolymer rubber (EPDM), polybutadiene rubber, polyisoprene rubber, styrene-butadiene Conjugated diene elastomers such as copolymer rubber, acrylonitrile-butadiene copolymer rubber, chloroprene rubber, and other non-conjugated dienes such as chlorosulfonated polyethylene rubber, acrylic rubber, epichlorohydrin rubber, chlorinated polyethylene rubber, and fluorinated rubber. elastomer components such as elastomers, about 3
It is preferably contained in an amount of 0 to 75% by weight, particularly 35 to 70% by weight.

The elastomer component of the adhesive layer is mainly the olefin elastomer mentioned above, or a mixture of the olefin elastomer and other non-conjugated diene elastomer and/or conjugated diene elastomer. Elastomeric components are optimal.

In addition to the elastomer component, the adhesive layer also contains other modifying polymers (modifying polymers), tackifiers, corrosion inhibitors, and inorganic fillers that are generally contained in adhesives. It may be blended.

Modifying polymers include, for example, olefin polymers such as polyethylene, ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, acrylate-ethylene copolymer, polypropylene, polybutene, and polyvinyl chloride, Examples include thermoplastic resins or liquid polymers such as polyamides and styrene polymers, and tackifiers include rosin and rosin derivatives, pinene resins, aliphatic hydrocarbon resins (C5 distillate), etc. minutes,
pentene, isoprene, 1,3-pentadiene, etc.), aromatic hydrocarbon resins (Cs fraction,
(styrenes, indenes, etc. alone or copolymers),
Examples include alicyclic hydrocarbon resins, coumaron resins, coumaron-indene resins, phenolic resins, naphthenic oils, and modified terpenes. Examples of corrosion inhibitors include inorganic corrosion inhibitors such as metal chromates, metal phosphates, metal phosphites, metal borate, molybinate, metal nitrite, and aromatic Metal salts of group carboxylic acids, aliphatic or aromatic compounds having multiple hydroxyl groups, organic corrosion inhibitors such as tannic acid, and inorganic fillers include talc, carbonaceous, silica, alumina, etc. , mica, carbon black, etc.

In this invention, the adhesive layer includes about 30 to 65% 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 tackifier, and about θ to 30% by weight of the inorganic filler. A thermoadhesive adhesive composition of 20% by weight has an adhesive strength (shear strength) of approximately 1.0 kg/c+J or more at room temperature and an adhesive strength (shear strength) at high temperatures. Approximately 0.01 kg at 80℃
/c4 or more, which is high at about 0.01 kg/cd or more at 1°0°C, and does not drop rapidly as the temperature rises above that, making it optimal.

In the coating material of this invention, if the elastomer component in the adhesive layer becomes too small, the adhesive will shear due to the heat shrinkage temperature of the heat-shrinkable coating material being about 80°C or higher, similar to general real-melt adhesives. It is not appropriate because the strength becomes extremely small or decreases rapidly.
Furthermore, if the elastomer component is too large, the adhesive force after cooling to room temperature will be reduced, which is not appropriate.

The tackifier is blended primarily to impart fluidity and tackiness to the adhesive, and if the amount is too small, these properties will be lost, which is not desirable.

In this invention, the heat-shrinkable coating material may be one in which the above-mentioned adhesive layer having high shear strength at high temperatures is provided on the entire surface area of one side of the heat-shrinkable crosslinked plastic sheet. If so, some areas of the cross-linked plastic sheet (for example, in a pipe with a gradually decreasing outer diameter, the inner surface of the sheathing material that is in contact with the larger diameter side; in a T-shaped pipe, the inner surface of the sheathing material that is in contact with the neck of a branch pipe) areas such as)
The above-mentioned first adhesive layer having high shear strength at high temperatures is provided, and the other part following this first adhesive layer is provided with a normal hot melt type adhesive layer having high adhesive strength at room temperature. Two adhesive layers may be provided.

As the second adhesive layer, for example, polyethylene,
Thermoplastic resins such as polypropylene, ethylene-vinyl acetate copolymer, acrylonitrile-ethylene copolymer, polyvinyl chloride, polyester, polyamide, etc. 30-80
Weight%, Asphalt (Bichi Komen) 0-50% by weight
, a hot melt type adhesive containing 10 to 20% by weight of a tackifier, 0 to 20% by weight of an inorganic filler, etc., has an adhesive strength (shear strength of about 5 to 30 kg/cm) at room temperature.
cJ ), and is suitable because it can flow and cope with small irregularities on the surface to be coated.

As the tackifier, inorganic filler, other additives, etc. in the second adhesive layer, those already mentioned can be used.

For example, the heat-shrinkable coating material of the present invention can be applied by:
First, as shown in Fig. 2, a heat-shrinkable covering material (sheet) 1 is wound around a deformed tube (reducer) 4 coated with a plastic resin coating layer of 5.5''. The overlapping parts of both ends of the sheet) 1 are connected with heat seal tape to form a cylinder, and then the knot-shaped covering material 1 is heated with the flame of a gas burner to heat-shrink it to form a deformed tube. This is done by bringing the coating material 1 into close contact with the surface of the coating material 1, heating the coating material 1, and bonding it with the heat-adhesive adhesive R3 of the coating material 1. In this construction, with conventionally known heat-shrinkable covering materials, the covering material would come off from the 5° plastic resin coating layer on the side with the larger outer diameter of the deformed tube during heat shrinkage, whereas the present invention With the heat-shrinkable coating material, the adhesive layer that has high shear strength at high temperatures during heat shrinkage prevents the coating material from coming off from the plastic resin coating N5" on the larger outer diameter side of the irregular-shaped tube. It was.

Note that the heat-shrinkable coating material of the present invention does not necessarily have to be a rectangular sheet as shown in FIG. , fan-like, or other shapes.

Examples and comparative examples are shown below.

In addition, in the examples and comparative examples, the shear strength of the adhesive was determined by overlapping two iron plates (125 m x 251 x 1°5 dragon) by 12 tm and interposing the adhesive in the overlapped part. The iron plates were heated to a bonding temperature of 130° C. for about 5 minutes, and the steel plates were simultaneously pulled in the direction of both ends using a universal testing machine, and measurements were taken according to the measurement method of ^STM D 1002.

Example 1 An adhesive having the composition shown below was kneaded at a temperature of 150° C. for 5 minutes using a knee-gut, and then rolled into an adhesive sheet having a thickness of 1.5 cages.

Butyl rubber 30% by weight Ethylene-propylene-nonconjugated diene copolymer rubber 2
5% by weight Polybutene 5% by weight Coumarone-indene resin 20% by weight Talc 10% by weight This adhesive sheet was measured using the above-mentioned shear strength measurement method, and the shear strength was 0.029 kg/cd at 80°C, 105~
1.014 kg/- at 10℃, 110-12
The shear strength does not suddenly decrease even at 0℃,
Further, at 20°C, it was 1.15 kg/cIll.

This adhesive sheet is attached to a cross-linked plastic sheet (thickness 1
．． OB, gel fraction 60%, heat shrinkage rate in the length direction 45%
, a heat shrinkable coating material (thickness: 2.5 m, width 11000 m, length Q;
A 2800m long seaport was formed.

As shown in Fig. 2, the heat-shrinkable covering sheet was applied to a reducer type deformed tube (outer diameter of large diameter part: 32 inches,
Wrap it around the small diameter part (outer diameter: 24 inches, length: 610 x ■) and join both ends with heat-sealing tape to form a cylinder, and heat the cylinder-shaped coating material with the flame of a gas burner for about 105 cm. The material was heated to ~110° C. and heat-shrinked to adhere tightly around the irregularly shaped tube, and heating was continued to bond the coating material around the irregularly shaped tube with the adhesive layer.

During the coating, the coating material did not cause large "slippage", especially on the larger diameter side of the irregularly shaped tube, and formed a good coating layer.

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

Ethylene-propylene-nonconjugated diene copolymer 20% by weight Ethylene-ethyl acrylate copolymer 25% by weight Coumarone-indene resin 45% by weight Microwax 10% by weight This adhesive sheet was measured using the shear strength measurement method described above. The result was 0.124 kg/cJ at 80℃, 105~
At 110℃, O,OO1kg/c+a, and at higher temperatures than 110℃, the shear strength decreases more rapidly, and
At 0°C, it was 24.2 kg/-.

Using this adhesive sheet, a heat-shrinkable covering sheet was formed in the same manner as in Example 1, and in the same manner as in Example 1, the periphery of the deformed reducer type tube was covered.

With this coating, when the cylindrical heat-shrinkable coating sheet is heated to about 90°C or higher, the coating sheet will shift abnormally on the larger diameter side of the irregularly shaped tube, exposing a wide area of the surface of the tube. It happened.

Example 2 A heat-shrinkable covering sheet had a first adhesive layer having the same adhesive composition as in Example 1 in a strip shape with a width of about 150 mm parallel to one edge in the longitudinal direction, and further , the same as in Example 1, except that the remaining surface of the covering sheet (width: approximately 850 mm strip surface) had a second adhesive layer having the same adhesive composition as in Comparative Example 1. A heat-shrinkable covering sheet was formed.

The heat-shrinkable covering sheet was used in the same manner as in Example 1, except that the first adhesive layer was overlapped with the coating layer on the large diameter part of the reducer type irregularly shaped tube. The circumference of the tube was coated.

During the coating, the coating material did not cause large "slippage", especially on the larger diameter side of the irregularly shaped tube, and showed strong adhesion at room temperature in areas where the tube diameter changed, forming a good coating layer.

[Brief explanation of drawings]

FIG. 1 shows an example of the heat-shrinkable coating material of the present invention (
a) A side view and a (bl) plan view. Figure 2 shows a situation in which the heat-shrinkable coating material of the present invention is wound around a deformed tube to be coated, and its both ends are joined to form a cylindrical body. FIG. 3 is a perspective view showing an example. FIG.
It is a perspective view which shows an example of the situation where the irregularly shaped pipe|tube similar to the figure is covered. 1; heat-shrinkable coating material, 2; crosslinked plastic layer, 3;
Adhesive layer, 4; irregular shape, tube (reducer), 5; coating layer, 6; heat seal tape. Patent applicant: Ube Industries, Ltd.

Claims (3)

[Claims] (1) In a heat-shrinkable sheathing material for irregularly shaped pipes in which a heat-shrinkable crosslinked plastic layer and a heat-adhesive adhesive are laminated, the entire area of one side of the sheathing material or one side of the sheathing material At high temperatures where the adhesive layer in some areas exhibits the greatest thermal shrinkage force of the coating material, it is approximately 0.005 to 0.05 *g.
/ ctA (8 STM D l0
02) A heat-shrinkable coating material characterized in that it is made of an adhesive whose main component is an elastomer material, and which can exhibit an adhesive force expressed by 02). (2) The shear strength of the adhesive layer is about 0.007 to
The heat-shrinkable coating material according to claim 1, which is within the range of 0.04 kg/call. (3) The heat-shrinkable coating material according to claim 1, wherein the elastomer material that is the main component of the adhesive layer is an olefin elastomer.