JPS61135729A - Heat restoring article - Google Patents

Abstract

PURPOSE:To obtain the heat restoring article, prominent in long period water resistant bonding force, by a method wherein the mixture of specified ratio of ethylene copolymer, specified ratio of polyamide resin, specified ratio of rubber and specified ratio of rust preventive is coated on the inner surface of the heat restoring article. CONSTITUTION:The layer of hot-melt adhesive, consisting of 5-30wt% of block copolymer, consisting of ethylenevinyl acetate copolymer having hydrolysis rate of 50-90wt%, 5-30pts.wt. of polyamide resin having amine value of 0.5-15 and styrenebutadien styrene having styrene containing rate of 30wt% or less or styrene-isoprene styrene, and 1.0-30pts.wt. of quick-lime or slaked lime, is provided at least one surface of the layer of heat restoring rubber or plastic. In case a molded product is tubular such as protective coating of electric cable, the layer is provided on the inner surface of the tube while the layer is provided on one surface of a sheet, coming to the inside of a tube when the sheet is rolled, in case the formed product is a sheet for preventing a steel pipe from corrosion.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat-recoverable article that has been improved to have strong adhesion to both various metals and plastics.

[Conventional technology]

It is well known to use hot melt adhesives to bond metals and plastic compositions. It is widely known that hot melt adhesives are applied to heat-recoverable articles, such as heat-shrinkable sleeves and sheet end caps, for use in connections and terminals of electrical cables, communication cables, steel pipes, steel pipes, and the like.

[Problem that the invention seeks to solve]

The hot-melt adhesives currently used for heat-recoverable articles are:
The various materials used (for example, iron, shell, lead, aluminum, stainless steel, steel, etc.), polyethylene, polypropylene, polyvinyl chloride, polyester, chloroprene rubber, ethylene propylene rubber, etc. It was difficult to adhere all the scales to the resin. Some adhered to polyethylene and metals, but did not adhere at all to polyvinyl chloride or polyester. On the contrary, it adhered to polyvinyl chloride and polyester, but did not adhere at all to polyethylene and polypropylene.

Conventionally, ethylene-vinyl acetate copolymers,
Ethylene obtained by hydrolyzing or thermally decomposing ethylene, ethyl acrylate copolymer, ethylene-glycidyl methacrylate copolymer, ethylene-glycidyl methacrylate-vinyl acetate terpolymer, ioolemer resin, ethylene acrylate copolymer Acrylic acid-
Acrylic acid ester terpolymers and the like are known. However, these adhesives had insufficient adhesion to lead-sheathed cables, polyvinyl chloride-sheathed cables, and the like. Furthermore, although these ethylene adhesives have excellent low-temperature impact resistance, they have low high-temperature shear adhesive strength and high-temperature peel strength, resulting in displacement of bonded parts and gas leaks during actual use.

On the other hand, polyvinyl chloride and polyester resin, copper, lead,
Polyamide resins, saturated polyester resins, and the like are known for adhesion to metals such as aluminum. However, these did not adhere to polyethylene sheathed cables and also had very poor low temperature impact properties. For this reason, if the cable was bent or subjected to impact at low temperatures, it would crack or peel at the adhesive, making it impractical.

However, in reality, the connection parts and terminal parts of power cables and communication cables are made of a combination of various materials, so it is extremely inconvenient that the adherends that can be bonded are limited as described above. be.

In addition, the environment in which electric wires and cables are used, as well as steel pipes and pipes, has recently become wider in temperature range from extremely low temperatures (about -40℃) to high temperatures (about SO'C), and even longer durability is required. As a result, there has been a demand for heat-recoverable articles coated with hot-melt adhesives that can withstand this, but there has not yet been a satisfactory product. In particular, when used for copper strip outer layer cables that contain steel materials that are easily corroded, or connections for steel pipes, etc., maintaining long-term adhesive strength with steel becomes a problem. The decrease in the value was so great that there was nothing that could be put to practical use.

[Means for solving problems]

The present invention provides a heat-recoverable article that has excellent adhesion between various plastics and metals, particularly steel materials, and has better low-temperature embrittlement and high-temperature adhesion than conventional products, and has excellent long-term water-resistant adhesive strength. That is, the present invention was first obtained by applying a mixture of a specific ethylene copolymer, a specific polyamide resin, a specific rubber, and a specific rust inhibitor in a predetermined ratio to the inner surface of a heat-recoverable article. The gist of this is that an ethylene-vinyl acetate copolymer with a hydrolysis rate of 5% to 90% by weight and an amine value of 0.5 are added to a necessary portion of at least one side of a heat-recoverable rubber or plastic layer. ~15 polyamide resin 5~
30 parts by weight and styrene, butadiene, styrene or styrene, isobrene, with a styrene content of 30% by weight or less.
A heat-recoverable article comprising a layer of a hot-melt adhesive made of a mixture of 5 to 30 parts by weight of a block copolymer made of styrene and 1.0 to 30 parts by weight of quicklime or slaked lime. .

In the present invention, the heat-recoverable rubber or plastic layer is
It may have a sheet shape, a tape shape, a tube shape, a cap shape with one end of the tube closed, or any other shape depending on the purpose of use.

Rubber or plastic is a polyolefin such as polyethylene, or a mixture of rubber and other plastics such as polyolefin. Heat recovery properties are determined by forming the above material into a desired shape, applying crosslinking treatment (chemical crosslinking, irradiation crosslinking, etc.), mechanically deforming it above its softening point, and cooling it to room temperature in the deformed state. A property given to a product that has the ability to recover its original shape when heated.

The location where the adhesive layer is provided differs depending on the shape of the molded product and the purpose of use, but when the molded product is a tube and is used as a protective covering for electric wires and cables, it is placed on the inner surface of the tube, and when the molded product is sheet-like, it is applied on the inner surface of the tube. When used for corrosion protection of steel pipes, it is provided on one side that becomes the inside when the steel pipe is wound and, if necessary, on a part of the outside surface and overlaps with the one side that becomes the inside.

The adhesive used in the heat recovery article of the present invention is ethylene vinyl acetate copolymer, polyamide resin and styrene/butadiene/styrene or styrene/isoprene/styrene/vinyl acetate copolymer.
It consists of three parts of a block copolymer made of styrene, and each component will be explained below.

Various types of hydrolyzate of the ethylene vinyl acetate copolymer can be obtained depending on the vinyl acetate content, melt index, and hydrolysis rate, but preferably the vinyl acetate content is 45% by weight or less, Hydrolysis rate is 5
0 to 90% by weight is preferable. The reason for this is that when the vinyl acetate content is 45% by weight or more, adhesive properties with polyolefins are poor, and heat stability and cold resistance are poor. Further, if the hydrolysis rate is less than 45% by weight, the melting point is low and the mechanical strength at high temperatures is low. If the hydrolysis rate is 90% by weight or more, the low-temperature impact resistance is poor and the melt viscosity is high. More preferably, after hydrolyzing the ethylene-vinyl acetate copolymer, 0.1 to 5.0% by weight of unsaturated carboxylic acid is graft-polymerized, thereby further improving the adhesion to the metal.

Examples of ethylene-vinyl acetate copolymers with a hydrolysis rate of 50 to 90% by weight include Dumilan D-291, D-229, D-159, and D-2251 manufactured by Takeda Pharmaceutical Company Limited.
G-222, G-452, G-422, C-2191,
C-2271, C-1591, C-1570, C-15
80, C-1550, C-2280, etc. can be used.

Furthermore, polyamide resins with an amine value of 0.5 to 15 are polymers made by reacting dibasic acids called dimer acids with diamines, such as unsaturated fatty acids such as tall oil fatty acids and soybean oil fatty acids, adipic acid, and azelaic acid. Acid, cepatic acid, etc. are added, and further ethylenediamine, hexamethylenediamine, influoronediamine, xylenediamine, 4-4'diaminodicyclohexylmethane, P-pimethylenedianiline, piperidine, trimethylhexamethylenediamine, alkanolamine, etc. Examples include reacted polyamide resins.

The obtained polyamide resin has a number average molecular weight of about 1500 to 2.
0000 range, ring and ball softening point is approximately 80°C ~
A temperature range of 180°C is preferable. Particularly in the present invention, those having an amine value of 0.5 to 15 are preferable, and those having an amine value of 0.5 to 15 are preferable.
If the amine value is less than 4, the reactivity is poor and the adhesion to metals is poor, and if the amine value is 16 or more, the reactivity is strong and it is easily susceptible to thermal deterioration, and furthermore, the compatibility with ethylene vinyl acetate copolymers is poor, resulting in poor adhesion. This is to cause a decline.

The polyamide resin having an amine value of 0.5 to 15 according to the present invention is manufactured by Henkel Japan Co., Ltd. and has a product name of Persalon 1128.1.
300.1188.1139.1140.1165.1
175 etc. and Fuji Kasei Kogyo Co., Ltd. parts name Tomide 39
4.509.1310.535.1350,512.5
65.500.575.1360 etc. can be used.

Furthermore, a block copolymer consisting of styrene/butadiene/styrene or styrene/isobrene/styrene with a styrene content of 30% by weight or less is manufactured by Shell Chemical Co., Ltd. Part name: CARIFLEX TR-11011TR-1102
, TR-1184, TR-1107, TR-1112 and Asahi Kasei Corporation parts name Toughblen A1 Turuprene T-4
No. 11 Asaprene T-431 and Trubulen T-475 can be used. In particular, block copolymers with a styrene content of 35% by weight or more are hard at low temperatures and do not exhibit rubber elasticity.
Not suitable as a low-temperature modifier for heat-recoverable articles. The block copolymer with a styrene content of 30% by weight or less is dispersed as fine rubber particles in the mixed resin of the ethylene vinyl acetate copolymer and polyamide resin, and exhibits a seabird structure, resulting in low-temperature brittleness and low-temperature impact properties. , low-temperature adhesion, etc. were greatly improved, and it exhibited properties that cannot be obtained with other rubbers or other component systems.

Furthermore, quicklime CaO or slaked lime Ca(OH)g is most suitable as the rust preventive agent of the present invention. Conventional anti-rust pigments such as lead cyanamid lead, zinc oxide, basic lead carbonate, zinc chromate, basic lead chromate, Bengara, zinc molybdate, zinc phosphate, aluminum phosphate, etc. are based on the above combinations. It had no effect on.

Of the four components of the adhesive used in the heat-recoverable article of the present invention, the resin component is 50 to 50% of the ethylene vinyl acetate copolymer.
It is preferably 90% by weight; if it is less than 45% by weight, it will have poor adhesion to polyolefin resins, and if it is more than 90% by weight, it will have poor adhesion to polyvinyl chloride resins and various metal bodies. Further, it is preferable that the polyamide resin is contained in an amount of 5 to 30% by weight, and if it is less than 3% by weight, the adhesion to polyvinyl chloride resin and various metal bodies is poor, and the water resistance is poor. This is because if it exceeds 35% by weight, it will have poor adhesion to the polyolefin resin and will have poor low temperature properties. Further, the block copolymer content is preferably 5 to 30% by weight; if it is less than 3% by weight, low temperature brittleness and low temperature impact properties will be poor, and if it is more than 35% by weight, adhesiveness with various metal bodies will be poor. It is necessary to add 1.0 to 30 parts by weight of quicklime or slaked lime to 100% by weight of these resins.

This is because if the amount is less than 1.0 parts by weight, the rust preventive performance is insufficient, and if it is more than 30 parts by weight, the adhesive becomes hard, the adhesive strength decreases, and the low-temperature embrittlement temperature worsens.

In this way, the four components are essential, but when the total resin component is 100 parts by weight, a small amount of thickening agent such as terpene resin, terpene phenol resin, phenol resin, alkyl phenol resin, coloring agent, filler, etc. It is also possible to add several tens of parts of an anti-aging agent or the like from the base.

The hot-melt adhesive thus obtained is shown in Figures 1 and 2.
Crosslinked thermoplastic resin or rubber as shown (1)
A heat-recoverable article is obtained by applying the hot-melt adhesive (2) to the inner surface of the article.

Cross-linked thermoplastic resin or rubber is polyethylene,
A mixture of one or more of ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, ethylene propylene rubber, silicone rubber, etc. is chemically crosslinked by electron beam irradiation crosslinking, peroxide, silane coupling agent, etc. After crosslinking, the outer layer of the heat-recoverable article can be obtained by heating the resin to a temperature above its melting point and causing it to expand.

〔Example〕

The following will explain based on examples.

Example 1 Dumilan D-215 (80% of hydrolysis rate) was used as an ethylene vinyl acetate copolymer (hereinafter abbreviated as EVA).
) and Persalon 1140 (amine value: 8, softening point: 140'C) as a polyamide resin (hereinafter abbreviated as PAm).
) and styrene-butadiene-styrene (SBS)
) as Kaliflex TRll0I (abbreviated as
Styrene content 30%) and quicklime powder 90:5:5:
5.80:10:10:10.70:15:15:15
．． 60: 20: 20:20゜50:30:20
A hot-melt adhesive was obtained by melt mixing (kneader mixing at 150° C. for 30 minutes) at a weight ratio of: 25.50: 20:30:30. This was press-molded at 150℃ and 2
．． On top of the QIuIL thick sheet, an adhesive was applied to a 100 ity heat-shrinkable sleeve (a cross-linked polyethylene pipe with an inner diameter of 5Q#J and a wall thickness of 3.0julLt heated and expanded to 1001ttsx) to a thickness of Q, 5Iua. The heat-recoverable article was used as a sample for the following performance test.

Performance Test 1 A low temperature embrittlement test was conducted on an adhesive sheet having a thickness of 2.0 mm and LL according to ASTM D-746 to determine the low temperature embrittlement temperature.

Performance Test 2 An adhesive sheet having a thickness of 2.0 & IL was subjected to a ring and ball softening point test using ASTM E-28 to determine the softening point of the adhesive.

Performance Test 3 The heat-recoverable article coated to a thickness of 0.5μ was heat-shrinked onto a 70mm steel pipe using a gas burner, and after cooling, the crosslinked polyethylene (PE) was peeled off at 90' to determine the adhesive strength. In the peel test, the adhesive strength was determined at -40°C, 25°C, and +80°C.

Further, the adhesive test pieces were immersed in 3% NaCl at 60°C, and after 1 month, 2 months, and 8 months, they were taken out and the peel strength was determined at 25°C.

The performance test results are shown in Table 1.

Example 2 Dumilan C-2270 (hydrolysis rate: 70%, unsaturated carboxylic acid content: 0.5%) as EVA, and PA
Persalon 1165 (amine value: 1.5, softening point: 160°C) as m and Califlex TR-1 as styrene-isobrene-styrene (hereinafter abbreviated as SIS)
101 (styrene content 14%) and slaked lime powder, 90
:5:5:5.80:10:10:10.70:15:
15:15, BO:20:20:20.50:30:2
A hot-melt adhesive was obtained by melt-kneading (mixing in a kneader at 150° C. for 30 minutes) at a weight ratio of 0:25.50:20:30:30. The obtained adhesive was subjected to the same performance test as in Example 1 to evaluate its performance. The results are shown in Table 2.

Example & EVA: Dumilan C-1550 (hydrolysis rate: 55%, unsaturated carboxylic acid content: 0.5%) was used as PAm.
Persalon 1358 (amine value: 6, softening point: 1)
40°C) and SBS with Turprene T-411 (styrene content 30%) and slaked lime powder in a ratio of 90:5:5:1.
0.80:10:10:10.70:15:15:10
．． 60:20:20:20.50:30:20:20.
Melt mixed wire at a weight ratio of 50:20:30:20 (150℃
The mixture was mixed in a kneader for 30 minutes to obtain a hot melt adhesive. The obtained adhesive was subjected to the same performance test as in Example 1 to evaluate its performance.

The results are shown in Table 3.

Comparative Example 1 The conventional hot-melt adhesives used were Evaflexum 220 (Mitsui Polychemical Co., Ltd. 1iEVA, hydrolysis rate 096) and Diamid T-450 (manufactured by Daicel Chemical Industries, Ltd., nylon 12 copolymer). ) and Tuffden 2000R
(Styrene-butadiene rubber manufactured by Asahi Kasei, styrene content 25%) and calcium carbonate powder in a ratio of 80:10:10:1.
0.60:10:20:20,40:3010:30
A hot-melt adhesive was obtained by melt mixing (kneader mixing at 150° C. for 30 minutes) at a weight ratio of . The obtained adhesive was subjected to the same performance test as in Example 1 to evaluate its performance. The results are shown in Table 4.

As can be seen from the performance test results in Tables 1, 2, and 8, the inner surface of the heat-recoverable article of the present invention has a hydrolysis rate of 50 to 9.
0% by weight of ethylene vinyl acetate copolymer and amine value of 0.
5-15 polyamide resin and styrene content 80% by weight
The following styrene-butadiene, ethylene or ethylene-
Heat-recoverable articles coated with a hot-melt adhesive made by kneading a block copolymer of isoprene and styrene with quicklime or slaked lime have a low low-temperature embrittlement temperature and have adhesive strength to various adherends from low to high temperatures. Are better.

In particular, ethylene-vinyl acetate copolymer is preferably graft-polymerized with 0.1 to 5.0% by weight of unsaturated carboxylic acid.
The polyamide resin preferably has a softening point in the range of 80 to 180°C. Also, the above blending ratio is 50-90:5-30:5
It can be seen that a ratio of ~30% by weight is excellent.

On the other hand, as can be seen from the results in Table 4, conventional kneaded products of ethylene-vinyl acetate copolymer, polyamide resin, and styrene-butadiene rubber have poor low-temperature embrittlement and a high softening point, so they are not compatible with various adherends. Although not included in the comparative example, commonly used inorganic fillers such as curk, clay, and sulfuric acid were used because they did not provide sufficient adhesive strength and the adhesive strength rapidly decreased when immersed in a corrosive atmosphere. As a result of adding 20 parts of each of calcium, alumina, alumina hydroxide, magnesium carbonate, lead oxide, iron oxide, etc. as substitutes for quicklime in the formulation system of Example 1, and examining the water-resistant adhesive strength, it was found that none of them had any anti-corrosion effect. After one month, rust had formed at the interface between the iron pipes and the pipes had naturally peeled off.

It turned out to be impractical.

〔Effect of the invention〕

From the above results, the heat-recoverable article with the special adhesive of the present invention has universal adhesion to various adherends, has excellent low-temperature embrittlement resistance, and has excellent adhesive strength at high temperatures. , which proves the significance of the present invention.

[Brief explanation of the drawing]

FIG. 1 shows an example of a tubular heat-recoverable article, in which (1) shows a crosslinked polyolefin resin and (2) shows a hot-melt adhesive. FIG. 2 shows an example of a three-pronged heat-recoverable article, in which (1) shows a crosslinked polyolefin resin and (2) shows a hot-melt adhesive. Figure 1 to Figure 2

Claims (4)

[Claims] (1) Add 50 to 90% by weight of an ethylene vinyl acetate copolymer with a hydrolysis rate of 50 to 90% and an amine value of 0.5 to 15 to a necessary portion of at least one side of the heat-recoverable rubber or plastic layer. Polyamide resin 5 to 30% by weight and styrene/butadiene with a styrene content of 30% by weight or less
It is characterized by providing a layer of a hot-melt adhesive made by mixing 5 to 30 parts by weight of styrene or a block copolymer of styrene, isoprene, and styrene and 1.0 to 30 parts by weight of quicklime or slaked lime. heat-recoverable articles. (2) The heat-recoverable article according to claim (1), wherein the ethylene-vinyl acetate copolymer is graft-polymerized with 0.1 to 5.0% by weight of an unsaturated carboxylic acid. (3) The heat-recoverable article according to claim (1), wherein the polyamide resin has a softening point of 80 to 180°C. (4) The heat-recoverable article according to claim (1), wherein the heat-recoverable article is made of a crosslinked polyolefin resin.