JPH06336580A - Hot-melt adhesive - Google Patents

Abstract

PURPOSE:To obtain a hot-melt adhesive which strongly bonds to plastics, fluororesins, and metals. CONSTITUTION:This hot-melt adhesive is prepd. by mixing an ethylene copolymer having an ethylene content of 50% or higher with a copolyamide in a wt. ratio of (95:5) to (5:95).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot melt adhesive having excellent adhesion to plastics, fluororesins and metals.

[0002]

2. Description of the Related Art It is well known to use hot melt adhesives for interlayer adhesion of multilayer structures such as multilayer tubes, multilayer sheets and multilayer heat shrinkable tubes, and for bonding to adherends such as plastics and metals. Kaisho 63-218344
The publication discloses a hot melt adhesive obtained by mixing a metal and a metal adhesive layer with a polyamide, a diene polymer and an acid or an acid anhydride. Also, JP-A-59-1436
No. 38 proposes a polyether ester as an adhesive layer between a polyester resin and an olefin-vinyl alcohol resin. Further, JP-A-56-122880 proposes a mixture of an ethylene vinyl acetate copolymer having a hydrolysis rate of 50 to 90% by weight and a polyamide resin having an amine value of 3 to 30 as a hot-melt adhesive of plastic and metal. ing. In addition, as a hot-melt adhesive for plastic and metal, Japanese Patent Publication No.
JP-A-59-5097 and JP-B-59-5097 propose a polyamide resin based on dimer acid. Further, in Japanese Patent Publication No. 56-17218, there are known examples of hot-melt adhesives for plastic and metal, such as ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, styrene butadiene block copolymer, styrene isoprene block copolymer, dimer vinegar base polyamide resin, It is disclosed that an acrylic resin or the like is kneaded with polybutene, polyisobutylene, chroman resin, terpene resin, terpene phenol resin, natural rosin, paraffin wax, microcrystal wax, asphalt, process oil, or the like.

[0003]

However, the hot-melt adhesive prepared by mixing the polyamide and the diene polymer and the acid or the acid anhydride, which is disclosed in the above-mentioned Japanese Patent Laid-Open No. 63-218344, is not compatible with the metal. The adhesiveness was excellent, but the adhesiveness with a polyolefin resin such as ethylene-vinyl acetate copolymer was insufficient. In addition, JP-A-59
-143638, a polyether ester, an ethylene vinyl acetate copolymer having a hydrolysis rate of 50 to 90% by weight and a polyamide resin having an amine value of 3 to 30 shown in JP-A-56-122880. Mixture and Japanese Patent Publication Nos. 56-17218 and 5
Similarly to the above, the hot-melt adhesive of a dimer acid-based polyamide resin disclosed in JP-A-9-5097 also had insufficient adhesion to a polyolefin resin such as an ethylene vinyl acetate copolymer.

Further, since the hot melt adhesive retains the performance of the multi-layer structure, it must be firmly adhered to both of them, and not only various plastics or metal adherends but also coating with fluororesin or fluororesin these days. However, there has been a demand for a hot-melt adhesive that strongly adheres to an adherend forming one of the multilayer structures. For example,
The heat-shrinkable tube used as the covering material for the crimp terminals and the covering material for automobile fuel line pipes uses a hot melt adhesive as the inner layer of the tube.
There has been a demand for an interlayer adhesive that strongly adheres to both the metal of the adherend and the polyolefin resin of the outer layer. Further, it firmly adheres to both the inner layer fluororesin and / or the polyolefin resin, which is being considered for the inner tube material of the fuel tube, and the outer layer polyamide resin and / or the multi-layered tube material formed of nitrile rubber or the like. Interlayer adhesives have been desired.

Therefore, an object of the present invention is to solve the above problems and to obtain a hot melt adhesive having excellent adhesive performance.

[0006]

DISCLOSURE OF THE INVENTION As a result of intensive studies to solve the above problems in hot melt adhesives, the present invention has revealed that hot melt adhesives composed of an ethylene copolymer having an ethylene content of 50% or more and a polyamide copolymer. It was found that a hot-melt adhesive having excellent adhesiveness to plastics, fluororesins and metals can be obtained by using the agent, and the present invention has been accomplished.

That is, the present invention provides a hot melt adhesive prepared by mixing an ethylene copolymer having an ethylene content of 50% or more and a polyamide copolymer in the range of 95: 5% by weight to 5: 95% by weight. It is a thing.

In the present invention, examples of the ethylene copolymer having an ethylene content of 50% or more include ionomer resins, ethylene vinyl acetate copolymers, ethylene-ethyl acrylate copolymers, ethylene-methacrylate copolymers, ethylene-methyl methacrylate copolymers. Examples thereof include polymers, ethylene-glycidyl methacrylate copolymers, ethylene-butene-1 copolymers and ethylene-propylene copolymers. When the ethylene content is less than 50%, the heat resistance is poor, so
Not preferable. The carboxyl group-containing ethylene copolymer is produced by a known method such as direct copolymerization or graft copolymerization of an α, β-unsaturated carboxylic acid component with the ethylene copolymer. Examples of the above α, β-unsaturated carboxylic acid component include acrylic acid, methacrylic acid, itaconic acid, maleic anhydride, fumaric acid and their monoesters, and preferably acrylic acid, methacrylic acid, maleic anhydride. Mention may be made of acids. Especially,
Addition of a small amount of maleic anhydride of 0.1 to 2% by weight is preferable because it has a sufficient modifying effect. For example, as the carboxyl group-containing ethylene copolymer, ethylene-butene-1-maleic anhydride copolymer and / or ethylene-propylene-maleic anhydride copolymer, ethylene-methacrylic acid-acrylic acid ester-maleic anhydride copolymer Examples include coalescing.

In the present invention, the polyamide copolymer means polycaproamide unit (nylon 6 unit), polyundecaamide unit (nylon 11 unit), polydodecaamide unit (nylon 12 unit), polyhexamethylene adipate. A copolymer containing at least two components of a polyamide-forming component such as a amide unit (nylon 66 unit), a polyhexamethylene sebacamide unit (nylon 610 unit), and a dimer acid polyamide, but is not limited thereto. For example, nylon 6 / dimer acid polyamide, nylon 12 / dimer acid polyamide, nylon 6/6
6, nylon 6/66/610, nylon 6/66/6
Examples of the copolymer include 10/12, and the melting point of the polyamide copolymer is preferably 150 ° C. or lower. Two or more components of the above copolymer may be blended and used by a method such as melt mixing. Further, the above-mentioned copolymer, a polyether ester amide copolymer, and a thermoplastic polyamide resin such as dimer acid polyamide may be blended by a method such as melt mixing and used.

The method of blending with an ethylene copolymer having an ethylene content of 50% or more is not limited, but for example, a method of melt mixing at a melting point of the both or more, or a method of blending the two into a tube or sheet molding machine. And the like. If the content of the ethylene copolymer or the polyamide copolymer having an ethylene content of 50% or more is less than 5% by weight, the effect of the present invention is small, which is not preferable.

Further, within a range not impairing the performance of the present invention,
Styrene such as styrene-isoprene block copolymer, styrene-isoprene-styrene block copolymer, styrene-butadiene block copolymer, styrene-butadiene-styrene block copolymer, styrene-ethylene-butadiene-styrene block copolymer It is also possible to add a thermoplastic elastomer such as a system elastomer, natural rubber, butyl rubber, polyester elastomer, or polyurethane elastomer. Furthermore, a known thickener,
Fillers, reinforcing agents, flame retardants, coloring agents, clarifying agents, plasticizers,
Ultraviolet ray blocking agents, anti-aging agents and the like can also be added.

The method for obtaining a multilayer structure using the hot melt adhesive of the present invention as an adhesive layer is not particularly limited, but it can be applied to, for example, a heat shrink tube. That is, two extrusion molding machines are used to form a cylindrical shape through a two-layer tube die so that the hot melt adhesive is on the inside and the outer layer material such as polyolefin is on the outside. It can be obtained by molding and cooling, and then cutting or winding it into a predetermined length through a take-up machine. If the melt viscosity of the polymer used at this time is low or the solidification time is long, in order to maintain the circular shape and size of the molten tube extruded from the die, the homing part should be cooled sufficiently by the internal pressure method, vacuum homing method, etc. The target tube-molded product can be obtained by taking into consideration such factors as adjusting the length of the cooling zone, the cooling temperature, and reducing the frictional resistance of the sliding surface so that solidification and roundness shaping can be obtained. Further, the heat-shrinkable tube is manufactured by continuously or intermittently crosslinking, heating and expanding in the radial direction and cooling.
The heat-shrinkable tube thus obtained exhibits the property of recovering its original shape when heated above the melting point of the polyolefin forming the outer layer, and the hot melt adhesive of the inner layer material is the outer layer material and the metal pipe. It adheres firmly to the adherend such as. Further, if the ring-and-ball softening temperature of the hot melt adhesive is less than 160 ° C., the hot melt adhesive tends to sag during the above-mentioned crosslinking, and the thickness becomes uneven, which is not preferable.

[0013]

According to the present invention, a hot melt adhesive comprising an ethylene copolymer having an ethylene content of 50% or more and a polyamide copolymer is obtained to obtain a hot melt adhesive having excellent adhesive performance with plastics, fluororesins and metals. To be

[0014]

EXAMPLES The effects of the present invention will be described below with reference to examples, but the present invention is not limited to these examples. In the examples,% and parts are based on weight unless otherwise specified.

The tests carried out in the examples were carried out by the following method.

Peel strength between the outer layer material and the hot melt adhesive:
The tube molded product was cut into a strip shape having a length of 100 mm and a width of 5 mm in the longitudinal direction, and the peel strength was obtained by a tensile tester. Adhesive strength between hot-melt adhesive and fluororesin: Using polyvinylfluoride (trade name Tedlar TWH15BE3) commercially available from DuPont Japan as the fluororesin, bond it with the hot-melt adhesive by hot pressing at 120 ° C. It was cut into a strip having a width of 100 mm and a width of 5 mm, and the adhesive strength was obtained by a tensile tester.

Bonding strength between hot-melt adhesive and metal: An aluminum sheet (manufactured by Toyo Aluminum Co., Ltd.) having a thickness of 50 μm is bonded to the hot-melt adhesive by a hot press at 120 ° C., and the length is 100 mm and the width is 5 mm. It was cut into strips, and the adhesive strength was determined with a tensile tester.

Reference Example 1 100 parts of an ethylene-propylene copolymer (Tufmer P0680, trade name of Mitsui Petrochemical Co., Ltd.) and 1 part of maleic anhydride were mixed and fed to an extruder set at 220 ° C. An ethylene-propylene-maleic anhydride copolymer was obtained. The amount of maleic anhydride grafted was measured by infrared spectrum, and it was confirmed that 0.79 part of maleic anhydride was grafted.

Reference Example 2 About 35% of caproamide units (6 units of nylon), about 1
5% of dodecamide unit (12 units of nylon), about 20
% Hexamethylene adipamide unit (nylon 66 unit) and about 30% hexamethylene sebacamide unit (nylon 610 unit) polyamide copolymer were produced by a known method, and the melting point was measured by a scanning calorimeter. By the way, 108 ℃
Met. Further, the relative viscosity (ηr) measured at 25 ° C. and 0.5% concentration in concentrated sulfuric acid was 1.95.

Example 1 Ethylene vinyl acetate copolymer (Sumitomo Chemical Co., Ltd., trade name Evatate D2011 vinyl acetate content 5%) was placed outside two extruders, and ethylene-propylene-maleic anhydride of Reference Example 1 was used. The molten polymer was extruded onto a cylinder through an internal pressure method tube two-layer molding die so that the polymer obtained by blending 80 parts of the copolymer and 20 parts of the polyamide copolymer of Reference Example 2 was on the inside, and was passed through a sizing plate in water. By cooling, a tube molded product (A-1) having an outer diameter of 7 mm, an inner diameter of 5 mm, an outer layer material thickness of 1.5 mm, and an inner layer material thickness of 0.5 mm was obtained.

Example 2 The same production method as in Example 1 was carried out using a polymer in which 50 parts of the ethylene-propylene-maleic anhydride copolymer of Reference Example 1 and 50 parts of the polyamide copolymer of Reference Example 2 were blended inside. A tube molded product (A-2) was obtained.

Example 3 A polymer prepared by blending 20 parts of the ethylene-propylene-maleic anhydride copolymer of Reference Example 1 and 80 parts of the polyamide copolymer of Reference Example 2 was used inside and the same production method as in Example 1 was used. A tube molded product (A-3) was obtained.

Example 4 Ethylene vinyl acetate copolymer (Sumitomo Chemical Co., Ltd., Evatate D2011 vinyl acetate content 5%) was added to three extruders.
On the outside, with a polymer obtained by blending 50 parts of the ethylene-propylene-maleic anhydride copolymer of Reference Example 1 and 50 parts of the polyamide copolymer of Reference Example 2 in the middle and the polyamide resin of nylon 6 inside. The outer diameter of the molten polymer was extruded onto a cylinder through a three-layer molding die for internal pressure method and then cooled in water through a sizing plate to give an outer diameter of 8
mm, the inner diameter was 5 mm, the outer layer material had a thickness of 1.25 mm, the intermediate layer had a thickness of 0.5 mm, and the inner layer had a thickness of 1.25 mm.

Comparative Example 1 Using the ethylene-propylene-maleic anhydride copolymer of Reference Example 1 inside, a tube molded product (B-1) was obtained by the same production method as in Example 1.

Comparative Example 2 The polyamide copolymer of Reference Example 2 was used on the inside, and Example 1 was used.
A tube molded product (B-2) was obtained by the same manufacturing method as described above.

Comparative Example 3 A polymer obtained by blending 80 parts of the ethylene-propylene-maleic anhydride copolymer of Reference Example 1 and 20 parts of dimer acid polyamide (Versamide 930, Henkel Hakusui Co., Ltd.) was used on the inside, and Example 1 and A tube molded product (B-3) was obtained by the same manufacturing method.

Comparative Example 4 80 parts of ethylene vinyl acetate copolymer (Takeda Pharmaceutical Co., Ltd.)
A polymer obtained by blending 20 parts of Dumilan C-1550) and a dimer acid polyamide (Henkel Hakusui Co., Ltd. Versamide 930) was used on the inside, and the same production method as in Example 1 was used.
A tube molded product (B-4) was obtained.

Peel strength between the outer layer material and the inner layer or middle layer hot melt adhesive of the tube molded articles obtained in Examples 1 to 4 and Comparative Examples 1 to 4, inner layer hot melt adhesive and fluororesin and metal. Table 1 shows the adhesive strength with.

[0029]

[Table 1] From Table 1, the hot melt adhesives of Comparative Examples 2 to 4 (B-2 to B-4) have insufficient peel strength from the polyolefin resin forming the outer layer material, and may peel from the outer layer material depending on the use conditions. It seems to be a problem. In particular, Comparative Example 2 (B-
The hot melt adhesive of 2) did not adhere at all.
Further, the hot melt adhesives of Comparative Examples 1, 3, 4 (B-1, B-3, B-4) were inferior in the adhesive performance with the fluorine resin and the metal.

Examples 1 to 4 (A-1 to A-4) of the present invention
It is clear that has a high peel strength with the outer layer material and a high adhesive strength with the fluororesin and the metal, and has excellent adhesive performance to various members. However, ethylene content is 50%
In the above-mentioned systems containing a large amount of ethylene copolymer components, the adhesive strength with the fluororesin tends to be low, and the peel strength with the outer layer material tends to increase, while in the systems containing many polyamide copolymer components, the adhesive strength with the fluororesin is high. And the peel strength with the outer layer material tended to be low.

[0031]

INDUSTRIAL APPLICABILITY The present invention uses a hot melt adhesive composed of an ethylene copolymer having an ethylene content of 50% or more and a polyamide copolymer, and thus has excellent adhesive performance to plastics, fluororesins and metals. It is expected that a hot-melt adhesive will be obtained, and the application will be expanded as an inter-layer adhesive layer of a multilayer structure and a hot-melt adhesive for various adherends.

Claims (5)

[Claims] 1. An ethylene copolymer having an ethylene content of 50% or more and a polyamide copolymer in an amount of 95: 5% by weight to 5:95.
Hot melt adhesive prepared by mixing in the range of wt%. 2. The hot melt adhesive according to claim 1, wherein the ethylene copolymer is a carboxyl group-containing ethylene copolymer. 3. The ethylene copolymer is one or more selected from a carboxyl group-containing ethylene-butene-1 copolymer, a carboxyl group-containing ethylene-propylene copolymer and an ethylene-methacrylic acid-acrylic acid ester copolymer. The hot melt adhesive according to claim 1. 4. The hot melt adhesive according to claim 1, wherein the polyamide copolymer is composed of a polyamide copolymer having a melting point of 150 ° C. or lower. 5. A heat-shrinkable polyolefin heat-shrinkable tube using the hot melt adhesive according to claim 1 as an inner layer, wherein the ring-and-ball softening temperature of the adhesive is 160 ° C. or higher, and the heat has a two-layer structure. Shrink tube.