JPS61136561A - Hot-melt adhesive - Google Patents

Abstract

PURPOSE:To provide a hot-melt adhesive exhibiting strong adhesion in the bonding of plastics to metal, esp. iron and steel materials, prepared by mixing specified ethylene copolymer, polyamide resin, rubber and rust preventive in a specified blend ratio. CONSTITUTION:The adhesive is prepared by blending (A) 50-90wt% ethylene/ vinyl acetate copolymer having a hydrolysis ratio of 50-90wt%, (B) 5-30wt% polyamide resin having an amine value of 0.5-15, (C) 5-30wt% styrene/ butadiene/styrene or styrene/isoprene/styrene block copolymer having a styrene content of less than 30wt% and (D) 1.0-30wt% quick lime or slaked lime. Preferred ethylene/vinyl acetate copolymer contains 0.1-5.0wt% graft polymerized unsatd. carboxylic acid and the preferred polyamide resin has a softening point of 80-180 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hot-melt adhesive composition that has been improved to have strong adhesion to both metals and plastics.

[Conventional technology]

It is well known to use hot melt adhesives to bond metals and plastic compositions. Hot melt adhesive e.g. heat shrink sleeve,
It is widely known that it can be applied to terminal caps, etc., and used for connection parts and terminal parts of electric cables, communication cables, steel pipes, steel pipes, etc.

[Problem that the invention seeks to solve]

Hot-melt adhesives currently in use are made of various materials used for the above-mentioned connections and terminals, such as metals such as iron, copper, lead, aluminum, stainless steel, and steel, as well as polyethylene, polypropylene, polyvinyl chloride, and polyester. It was difficult for scales to adhere to synthetic resins such as polypropylene rubber, ethylene fluoroprene rubber, and ethylene fluoropyrene rubber. Some types of adhesive bonded to polyethylene and metals, but there was no bond 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 copolymer, ethylene-dityl acrylate copolymer, ethylene-vinyl acrylate copolymer, ethylene-vinyl acrylate copolymer, etc.
Glycidyl methacrylate copolymer, ethylene, glycidyl methacrylate-vinyl acetate terpolymer, ioolemer resin, ethylene acrylic acid-acrylic ester terpolymer obtained by hydrolyzing or thermally decomposing ethylene acrylic ester copolymer Combination etc. 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, and during actual use, the bonded area may shift and regas leakage may occur.

On the other hand, polyamide resins, saturated polyester resins, and the like are known for adhering polyvinyl chloride or polyester resins to metals such as copper, lead, and 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. .

In addition, the environment in which electric wires and cables are used, as well as steel pipes and pipes, has recently expanded to a wide temperature range from extremely low temperatures (about -40°C) to high temperatures (about 80°C), and even longer durability is required. As a result, there was a need for a hot-melt adhesive that could withstand this, but there was still no satisfactory material. Copper band outer layer cables containing steel materials that are particularly prone to corrosion,
When used for connections of steel pipes, etc., maintaining long-term adhesive strength with iron becomes a problem, and the adhesive strength deteriorates significantly in highly corrosive seawater or high-temperature water, making it impossible to find a product that can withstand practical use.

[Means for solving the problems] The present invention is a heat-melting type that has excellent adhesion between various plastics and metals, especially steel materials, and has better low-temperature embrittlement and high-temperature adhesion than conventional ones, and has excellent long-term water-resistant adhesive strength. Provide adhesive.

That is, the present invention was first obtained by mixing a specific ethylene copolymer, a specific polyamide resin, a specific rubber, and a specific rust inhibitor in a predetermined ratio. Ethylene-vinyl acetate copolymer with a decomposition rate of 50 to 90% by weight, 5 to 30 parts of polyamide resin with an amine value of 0.5 to 15, and styrene/butadiene-styrene or hastyrene with a styrene content of 30% by weight or less. Block copolymer consisting of isoprene and styrene 5 to 30
% by weight and 1.0 to 30 parts by weight of quicklime or slaked lime.

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-251 manufactured by Takeda Pharmaceutical Co., Ltd.
, G-222, G-252, G-422, C-2191
゜C-2271, C-1591, C-1570, C-1
580, C-1550, C-2280, etc. can be used.

Sarashi; As a polyamide resin with an amine value of 0.5 to 15, it is a polymer made by reacting a dibasic acid called dimer acid with a diamine. For example, adipic acid is added to an unsaturated fatty acid such as tall oil fatty acid or soybean oil fatty acid. , azelaic acid, sepatic acid, etc., and further -ethylene diamine, hexamethylene diamine, influorone diamine, xylene diamine, 4-4'diaminodicyclohexylmethane, P-
Examples include polyamide resins reacted with P'methylene dianiline, piperidine, trimethylhexamethylene diamine, alkanolamine, and the like.

The obtained polyamide resin has a number average molecular weight of about 1500 to 2.
0000 range, with a ring and ball softening point of about 80'C~
A temperature range of 180°C is good. In particular, in the present invention, those with an amine value of 0.5 to 15 are preferable, and those with an amine value of 0.
．． 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 of the present invention is manufactured by Henkel Japan Co., Ltd. under the trade name Parson on 1128.180.
0.1138.1189.1140,1165.117
5th grade and Fuji Kasei Kogyo special product name Tomide 894.5
09.1310.585.13501512.565.
500°575.1360 etc. can be used.

Furthermore, block copolymers consisting of styrene-butadiene, styrene, or styrene-isoprene/styrene with a styrene content of 30% by weight or less include Shell Kagaku special trade names Kaliflex TR-1101, TR-1102,
TR-1184, TR-1107, TR-1112, Asahi Kasei Co., Ltd. product name Toughblane A1 Turuprene T-411
, Asaprene T-4311 and Turprene 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 hot-melt adhesives. The Nofrock copolymer with a styrene content of 30% by weight or less is obtained by dispersing fine JI as 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 resistance. , low-temperature adhesion, etc. were greatly improved, and it exhibited properties that could not be obtained with Ike's rubber or other component systems.

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

Among the blending ratios of the four components of the present invention, the resin content is preferably 50 to 90% by weight of ethylene vinyl acetate copolymer. If it is less than 45% by weight, it will have poor adhesion with polyolefin resin, and if it is more than 90% by weight, polyvinyl chloride copolymer This is because the adhesion to resins and various metal bodies becomes poor. Further, the content of the polyamide resin is preferably 5 to 30% by weight, and if it is less than 3% by weight, the adhesiveness 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, the adhesiveness with the polyolefin resin will be poor and the low-temperature properties will be poor. Further, the block copolymer content is preferably 5 to 30% by weight, because 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. These resin parts 1
Quicklime or slaked lime is 1.0 to 3% by weight
It is necessary to add 0 parts by weight. This is because if the amount is less than LO parts by weight, the rust prevention performance will be insufficient, and if it is more than 30 parts by weight, the adhesive will be hard and the adhesive strength will decrease, resulting in a worsening of the low-temperature embrittlement temperature.

In this way, the four components are essential, but a small amount of thickening agents such as terpene resin, terpene phenol resin, phenol resin, alkylphenol IIt fat, coloring agent, and filler are added to the total of 100 parts by weight of the above resin components. It is also possible to add several tens of parts of antioxidants and the like from the base.

〔Example〕

The following will be explained based on examples.

Example 1 Ethylene vinyl acetate copolymer (hereinafter abbreviated as EVA)
Dumilan D-215 (hydrolysis rate: 80%) and Persalon 1140 (amine value: 8, softening point: 140°C) as polyamide resin (hereinafter abbreviated as PAm).
) and styrene-butazine-styrene (hereinafter abbreviated as SBS), Cauliflex TRll0I (styrene content 30%) and quicklime powder were mixed in a ratio of 90:5:5:5.
．． 80:10:10:”10170:15:
15:15.60:20:20:20゜50:30:2
A hot-melt adhesive was obtained by melt mixing (1-, kneader mixing 3° at 50°C) at a weight ratio of 0:25.50:20:30:30. Further press molding at 150'C gives a thickness of 2.0IuL and 0.5! A thick adhesive sheet was used as a sample for the next performance test.

Performance test 1゜2.0 thickness adhesive sheet ASTM D 7461C
A low temperature embrittlement temperature test was conducted to determine the low temperature embrittlement temperature.

Performance test 2゜2.0! The thick adhesive sheet was subjected to a ring and ball softening point test using A-5TME-28 to determine the softening point of the adhesive.

Performance test 3゜Q, a 5 IuL thick adhesive sheet was mixed with a 2.0 mm thick crosslinked polyethylene sheet. It was inserted between a steel plate of OB thickness and press-bonded for 10 minutes at 0°C, and after cooling, the A S TM D-
A 180° peel test was conducted using 903. The peeling temperature was tested at -40°C, 25°C, and SO'C atmosphere.

Furthermore, the adhesive test piece was immersed in 60'C3% NaCl and taken out after 1 month, 2 months, and 3 months, 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
m is Persalon 1165 (amine value: 1.5, softening point: 160°C), styrene, isoprene-styrene (
Califlex TR-1 (hereinafter abbreviated as SIS)
101 (styrene content 14%) and slaked lime powder, 90
:5:5:30180:10:10:25.70:15
:15:20,60:20:20:15.50:30:
A hot-melt adhesive was obtained by melt-kneading (mixing in a kneader at 150'C for 30 minutes) at a weight ratio of 20:10, 50:20:30:5. 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 3 Dumilan C-1550 (hydrolysis rate: 55%, unsaturated carboxylic acid content: 0.5%) as EVA and PA
Persalon 1358 (amine value: 6, softening point: 140°C) as m, Turprene T-411 (styrene content bO%) as SBS, and slaked lime powder at 9o:5:5:1
0.80: 10: 10: 10170:15
Knee i 5: 10.60:20:20:20.5o
:30:20:20.50:20: and 30:20 were melt-kneaded (kneader at 150°C 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 Evaflex Z22O (EVA manufactured by Mitsui Polychemical Co., Ltd. with a hydrolysis rate of 0%) and Diamid T-450 (Nylon 12 copolymer manufactured by Daicel Chemical Industries, Ltd.). ) and Tuffden 200OR (styrene-butadiene rubber manufactured by Asahi Kasei Corporation, styrene content 25%)
) and calcium carbonate powder at 80:10:10:10.6
0:20:20:20.40:30:30:3
Melt kneading at a weight ratio of 0 (kneader kneading at 150°C for 30 minutes)
A hot-melt adhesive was obtained. The obtained adhesive is Example 1
A performance test similar to that was conducted to evaluate the performance. The results are shown in Table 4.

1! i Shil! 3 1-・ As can be seen from the performance test results in Table 2, Table 3, Table 4, Tables 1, 2, and 3, ethylene vinyl acetate with a hydrolysis rate of 50 to 90% by weight of the present invention A heat-melting type made by kneading a polymer, a polyamide resin with an amine value of 0.5 to 15, a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene with a styrene content of 30% by weight or less, and quicklime or slaked lime. Adhesives have a low low-temperature embrittlement temperature and have excellent adhesive strength to various adherends from low to high temperatures. In particular, the ethylene-vinyl acetate copolymer may be graft-polymerized with 0.1 to 5.0% by weight of unsaturated carboxylic acid, and 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
: It can be seen that a ratio of 5 to 30% by weight is excellent.

On the other hand, as can be seen from the results in Table 4, conventional ethylene vinyl acetate copolymer, polyamide resin and styrene
Kneaded products of butadiene rubber have poor low-temperature embrittlement and a high softening point, making it difficult to obtain sufficient adhesive strength with various adherends, and the adhesive strength rapidly decreases when immersed in a corrosive atmosphere, making it unsuitable for practical use. It turned out that it wasn't. Furthermore, although not mentioned in the comparative example, commonly used inorganic fillers such as talc, clay, calcium sulfate, alumina, aluminum hydroxide, magnesium carbonate, and lead oxide are used as substitutes for quicklime in the formulation system of Example 1. As a result of adding 20 parts of each type and examining the water-resistant adhesive strength, it was found that none of them had an anticorrosive effect, and after one month, rust occurred at the interface of the iron plate and spontaneously peeled off.

〔Effect of the invention〕

From the above results, the hot-melt adhesive of the present invention has excellent long-term adhesive strength even in a corrosive atmosphere, is resistant to low-temperature embrittlement, and has excellent adhesive strength at high temperatures, which demonstrates the significance of the present invention. This proves that

Claims (3)

[Claims] (1) Ethylene-vinyl acetate copolymer with a hydrolysis rate of 50-90% by weight and an amine value of 0.5-90% by weight
5 to 30% by weight of polyamide resin No. 15, 5 to 30% by weight of a block copolymer consisting of styrene, butadiene, styrene or styrene, isoprene/styrene with a styrene content of 30% by weight or less, and 1.0% of quicklime or slaked lime.
-30 parts by weight of a hot-melt adhesive. (2) The hot-melt adhesive according to claim (1), wherein the ethylene vinyl acetate copolymer is graft-polymerized with 0.1 to 5.0% by weight of unsaturated carboxylic acid. . (3) The hot-melt adhesive according to claim (1), wherein the polyamide resin has a softening point of 80 to 180°C.