JPH10102019A - Hot-melt adhesive composition and bonding of polyolefin material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition exhibiting low-temperature bonding performances and high-temperature bonding performances to a polyolefin material, by blending a specific base polymer with a tackifier resin compatible with the polymer and an incompatible solid tackifier resin. SOLUTION: This composition comprises (A) a base polymer comprising an ethylene-(meth)acrylic acid ester copolymer (preferably one having 40-90wt.% ethylene content and 100-2,000dg/minute melt index by JIS K6,730) and/or a polyolefin-based resin (preferably one having 1,000-50,000Pa.S melt viscosity at 190 deg.C), (B) a tackifier resin in a liquid at a normal temperature and/or a tackifier resin (preferably rosin resin, etc.) in a solid state having compatibility with the component A and (C) a tackifier resin in a solid state at a normal temperature, having incompatibility with the component A. Preferably, the component B has 30-120 deg.C softening point by a ring and ball method. Preferably, the component C has 100-160 deg.C softening point by the ring and ball method.

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 composition for bonding a polyolefin material and a method for bonding a polyolefin material using the same.

[0002]

2. Description of the Related Art Polyolefin materials such as polyethylene and polypropylene are inexpensive and easily available,
It is widely used in various industrial fields because of easy processing into sheets, foams, various molded products, and the like. However, polyolefin materials have low surface energy,
It is also known that bonding with an adhesive is difficult, and bonding using an organic solvent-based adhesive having good wettability with an adherend is widely performed.

[0003] However, regulations on organic solvents are becoming stricter from the viewpoint of environmental and health effects, and there is a demand for a bonding method using an adhesive that does not use organic solvents. As one of them, various attempts have been made to bond with a hot melt adhesive. Hot melt adhesives that are widely used generally comprise a base polymer such as an ethylene-vinyl acetate copolymer or a styrene block copolymer, and a tackifying resin compatible with the base polymer. Wax or oils.

According to the hot melt adhesive, particularly when a polyolefin material is bonded, a tackifier resin having compatibility with a base polymer is used, so that both low-temperature adhesiveness and high-temperature adhesiveness can be achieved. There was a problem that it was difficult. That is, a tackifying resin having a low softening point is often used to improve the adhesiveness at a low temperature, but in this case, the cohesive force at a high temperature is reduced, the heat-resistant adhesiveness is reduced, and conversely, at a high temperature, When a tackifying resin having a high softening point is used to improve the adhesiveness, there is a problem that the low-temperature adhesiveness is deteriorated.

[0005] As a solution to such a problem, attempts have been made to improve a base polymer so that both low-temperature adhesion and high-temperature adhesion can be achieved. For example, JP-A-7-4855
No. 2 discloses a hot melt adhesive containing an ethylene n-butyl acrylate copolymer as a base polymer and further containing a tackifier resin and a wax.

The hot-melt adhesive described in the above publication also exhibits good low-temperature and high-temperature adhesiveness to paper materials such as corrugated cardboard, but low-temperature adhesiveness and high-temperature adhesiveness for bonding polyolefin materials. There is a problem that the compatibility of the two is insufficient.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems and provides a hot-melt adhesive composition exhibiting excellent low-temperature adhesive performance and high-temperature adhesive performance to polyolefin materials, and this hot-melt adhesive. It is an object of the present invention to provide a method for bonding a polyolefin material using an agent composition.

[0008]

According to the present invention, there is provided a hot melt adhesive composition comprising a base polymer (a) comprising an ethylene- (meth) acrylate copolymer and / or a polyolefin resin; (B) a liquid tackifying resin and / or a tackifying resin which is solid at room temperature and is compatible with the base polymer; and a tackifier which is solid at room temperature and is incompatible with the base polymer. It is characterized by comprising resin (c).

[0009] The base polymer (a) ethylene-
Examples of the (meth) acrylate constituting the (meth) acrylate copolymer include, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate,
N-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, glycidyl methacrylate, methyl methacrylate,
Ethyl methacrylate and the like. These may be used alone or in combination of two or more. Further, a third component such as carbon monoxide or maleic anhydride may be copolymerized.

The ethylene content in the ethylene- (meth) acrylate copolymer is preferably from 30 to 98% by weight, more preferably from 40 to 90% by weight. or,
The melt index of the ethylene copolymer is JIS
10 to 5000 dg / mi as measured by K6730
The range of n is preferable, More preferably, it is 100-2000.
dg / min. Two or more ethylene copolymers may be used in combination, and in this case, the mixture may be selected so that the melt index of the mixture falls within the above range.

Polyolefin resins include polyethylene, polypropylene, polyhexene, polyoctene,
Ethylene-propylene copolymer, propylene-butene copolymer, propylene-hexene copolymer, propylene-
A crystalline or amorphous polyolefin such as an octene copolymer and an ethylene-propylene-butene copolymer can be used.

The melt viscosity of the polyolefin resin is 1
It is preferably in the range of 100 to 100000 mPa · s at 90 ° C., more preferably 1000 to 50 mPa · s.
000 mPa · s. Even when two or more polyolefin-based resins are used in combination, it is preferable to select the mixture so that the melt viscosity of the mixture falls within the above range.

Examples of the tackifying resin (b) which is liquid at normal temperature include liquid rosin resin, liquid terpene resin, liquid alicyclic petroleum resin and the like. As the tackifying resin (b) which is solid at room temperature and is compatible with the base polymer, the cloud point of a mixture having a weight ratio to the base polymer of 1: 1 according to the measurement method of JIS K2269 is determined. Lower than the ring-ball method softening point, and is preferably selected from rosin-based resins, terpene-based resins, petroleum-based resins, cumarone-based resins and the like according to the base polymer.

The rosin-based tackifying resin includes gum rosin, wood rosin, polymerized rosin, disproportionated rosin,
Hydrogenated rosin, dimerized rosin; esters of these various rosins with pentaerythritol, glycerin, diethylene glycol, etc .; rosin phenol resins.

As the terpene-based tackifying resin,
Examples thereof include terpene resins, copolymers of terpene and styrene, copolymers of terpene and α-methylstyrene, copolymers of terpene and phenol, and hydrogenated products thereof.

Examples of the tackifying resin of the petroleum resin include aliphatic petroleum resins, alicyclic petroleum resins, aromatic petroleum resins, petroleum resins of aliphatic-aromatic copolymers, and hydrogenated products thereof. However, examples of the tackifier resin of the coumarone-based resin include a coumarone resin and a coumarone-indene resin. The tackifier resin may be used alone, or two or more resins having different types and different softening points may be used in combination.

The above tackifying resin has a ring-ball method softening point of 30.
To 140 ° C., more preferably 30 to 1 ° C.
It is at 20 ° C.

The tackifying resin (c) which is solid at room temperature and is incompatible with the base polymer has a cloud point of a mixture having a weight ratio to the base polymer of 1: 1 according to the measuring method of JIS K2269. It is higher than the ring and ball softening point temperature of the tackifier resin, or refers to a mixture that does not become transparent even when heated to 200 ° C., and the rosin-based resin described above,
The terpene resin, petroleum resin, cumarone resin, alkylphenol resin, xylene resin, maleic resin, rosin-modified maleic resin, and the like are selected according to the base polymer. The tackifying resin (c) may be used alone, or two or more kinds having different types and softening points may be used in combination.

The tackifier resin (c) preferably has a softening point in the ring and ball method of 100 to 180 ° C, more preferably 100 to 160 ° C.

The mixing ratio of the base polymer (a), the tackifying resin (b) and the tackifying resin (c) is preferably as follows. Hereinafter, all percentages are (a), (b),
% By weight in the composition comprising (c). In the case of the base polymer (a): ethylene- (meth) acrylate copolymer, the content is preferably from 20 to 80%, more preferably from 30 to 60%. If it is less than 20%, the low-temperature adhesiveness decreases, and if it exceeds 80%, the melt viscosity becomes too high and the workability deteriorates.

20 to 80 in the case of a polyolefin resin
% Is preferable, and more preferably 40 to 70%. 2
If it is less than 0%, the low-temperature adhesiveness decreases, and if it exceeds 80%, the high-temperature adhesiveness decreases.

Tackifying resin (b): The compounding ratio is 10 to 5
0% is preferable, and 10 to 40% is more preferable.
If it is less than 10%, low-temperature adhesiveness is not exhibited, and if it exceeds 50%, high-temperature adhesiveness cannot be obtained.

Tackifying resin (c): 5 to 50
% Is preferable, and more preferably 10 to 30%. 5
%, High-temperature adhesiveness is not exhibited, and if it exceeds 50%, low-temperature adhesiveness cannot be obtained.

The hot melt adhesive composition of the present invention comprises
Wax, softener, filler, antioxidant,
Colorants (pigments, dyes), ultraviolet absorbers, and the like may be added. Wax is used when it is necessary to lower the viscosity and improve the solidification rate. Examples of such waxes include paraffin wax, microcrystalline wax, Fischer-Tropsch wax, polyethylene wax, polypropylene wax, and oxidized wax obtained by oxidative decomposition of these waxes; maleic acid,
An acid-modified wax grafted with an unsaturated (anhydride) carboxylic acid such as maleic anhydride, fumaric acid, acrylic acid, methacrylic acid and the like can be mentioned.

The compounding ratio of the wax is preferably at most 40%, more preferably at most 30%. If it exceeds 40%, low-temperature adhesion cannot be obtained.

Examples of the softening agent include process oils such as paraffin oil, naphthenic acid oil, and aroma oil known as rubber developing oil; plasticizers such as phthalic acid ester and phosphoric acid ester; liquid polybutene, liquid polybutadiene; These hydrogenated products and liquid polyisoprene are exemplified. These may be used alone or in combination of two or more.

The blending ratio of the softener is preferably 40% or less, more preferably 30% or less. If it exceeds 40%, high-temperature adhesion cannot be obtained.

As fillers, calcium carbonate, clay,
Examples include talc, carbon black, silica and the like.

Examples of the antioxidant include known ones such as a hindered phenol type, a hindered amine type, a phosphorus type and a sulfur type, and these may be used alone or in combination of two or more.

The equipment for producing the hot melt adhesive composition of the present invention may be any equipment having a function of heating, stirring or kneading, and the equipment conventionally used for producing hot melt adhesives may be used as it is. it can. Examples of such equipment include single or twin screw extruders, sigma plate mixers, ribbon mixers, butterfly mixers, kneaders, and the like.

As a method for producing the hot melt adhesive composition, a conventionally performed method can be employed as it is. For example, the adhesive composition can be obtained by putting the compounding materials into the above facility heated to 100 to 250 ° C, preferably 140 to 200 ° C, and mixing while heating.

The product may be directly supplied from the manufacturing apparatus to the coating apparatus via a heating pipe or a heating vessel, or may be cooled once and supplied as a solid. In order to supply as a solid, a molded product consisting of an adhesive alone such as pellets, beads, strips, sticks, sheets, films, and lumps is used. In this case, it is desirable that the solid state is not sticky.

If the solid state has tackiness, the surface is supplied with a non-tacky coating. At the time of bonding, the coating is used as it is. Examples of the non-stick coating include a thin layer coating of silicone oil, wax, lubricant, etc .; coating with a film of polyethylene, amorphous polypropylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, etc. Is mentioned.

When the solid adhesive composition has tackiness, it may be subjected to a removable detackifying treatment.
For example, it is supplied in a state of being wrapped with release-treated paper or a plastic film, or in a state of being filled in a metal or paper can.

Next, a method for bonding a polyolefin material according to claim 3 will be described. The invention according to claim 3 is
In bonding a polyolefin material to each other or a polyolefin material and another material, a method of bonding a polyolefin material using the hot melt adhesive composition according to any one of claims 1 and 2 for one of the materials.

Examples of the polyolefin material include films such as polyethylene and polypropylene, sheets, foamed sheets, nonwoven fabrics, and molded products. These polyolefin materials may be laminated or coated with other materials by an adhesive, heat fusion, or coextrusion.

Other materials other than polyolefin materials include paper; metal materials such as iron, aluminum, nickel, tin, lead, and alloys thereof; ethylene-vinyl acetate copolymer, polyvinyl alcohol, polyester, and polyvinyl chloride. , Polystyrene, polycarbonate, acrylonitrile-butadiene styrene copolymer, polyurethane,
Synthetic resins such as acrylic resins; glass and other ceramic materials; and the like, such as sheets, films, and molded articles.

The following method can be adopted as this bonding method. (1) An adhesive in a heated and melted state is applied to one of the materials, and the other material is bonded until the adhesive is cooled and solidified. Specifically, (a) the adhesive is heated and melted by a hot melt applicator, and is applied in a dot, peed, surface, spiral, etc. through a nozzle or a slit. (B) The adhesive is heated on a heating roll. Melting and applying with a roll, (c) extrusion coating with an extruder, and the like are employed.

(2) An adhesive in a heated and melted state is applied to one of the materials, and once cooled, the other material is bonded. Specifically, (a) when bonding, the adhesive is reheated and bonded in a molten state; (b) when the adhesive has tackiness, it is bonded and bonded as it is (c)
For example, a method in which the bonding surface of the material to which the adhesive is not applied is heated to a temperature equal to or higher than the softening point of the adhesive and bonded together is adopted. As a method of reheating, there are a method of heating the adhesive or the material with a hot plate, hot air, infrared rays, or the like, and a method of heating the adhesive or the material by electromagnetic wave induction heating or the like.

In the above cases (1) and (2), the adhesive may be applied in a foamed state by mixing carbon dioxide gas, nitrogen gas or the like.

According to a third aspect of the present invention, in the method of bonding a polyolefin material, the polyolefin material is formed into a sheet or a film.
The hot melt adhesive composition described above is arranged between the materials to be bonded, and bonded by means such as a hot press.

The method of bonding the hot melt adhesive composition and the polyolefin material of the present invention is used for assembling and sealing paper containers such as cardboard and cartons; for producing automobile parts, electric / electronic parts, sanitary articles, books, magazines, etc. Used.

[0043]

Embodiments of the present invention will be described below. (Examples 1 to 3) (Comparative Examples 1 to 3) A hot melt adhesive composition was obtained by melt-mixing the ethylene-based copolymer, tackifier resin, wax and antioxidant shown in Table 1 at 180 ° C. Was.

[0044]

[Table 1]

The components used in the table are as follows. Base polymer (a): (a) 1; ethylene-ethyl acrylate copolymer (ethyl acrylate content 25% by weight, melt index 8)
00 dg / min, manufactured by Mitsui Dupont Polychemicals Co., Ltd., trade name "Evaflex A-715") (a) 2; ethylene-butyl acrylate copolymer (butyl acrylate content 35% by weight, melt index 4)
00dg / min, manufactured by Du Pont-Mitsui Polychemicals Co., Ltd., trade name "Elvacs EP-4113W") Tackifying resin (b): (b) 1; stabilized rosin ester resin (softening point 115
℃, Arakawa Chemical Co., trade name “Super Ester A11
5)) (b) 2; hydrogenated rosin ester resin (softening point 75 ° C., manufactured by Arakawa Chemical Co., trade name “Ester Gum H”) Tackifying resin (c): rosin-modified maleic resin (softening point 145 ° C., Arakawa Chemical Co., Ltd., product name "Marquid No.
5)) Wax: Fischer-Tropsch wax (melting point 10)
5 ° C, manufactured by Sasol Corporation, trade name “Sasol Wax H
1)) Antioxidant: hindered phenol type (trade name “Irganox 1010” manufactured by Ciba-Geigy)

The hot melt adhesive compositions of the above Examples and Comparative Examples were evaluated for the following properties.
It was shown to. (1) Measurement of low-temperature adhesiveness / peeling strength A hot-melt adhesive composition heated and melted at 180 ° C. was applied to a 2 mm-thick polypropylene plate at a coating amount of about 3 g / m ^{2 in} a single bead form. Two seconds later, a 40 μm-thick polypropylene film was attached to prepare a test piece. Using an "Autograph AG-10TB" manufactured by Shimadzu Corporation, a tensile speed of 300 mm /
A 180-degree peel test was performed in minutes, and the maximum strength was defined as the peel strength.

(2) Measurement of high-temperature adhesiveness / shear creep fall time A hot-melt adhesive composition melted on a hot plate heated to 180 ° C. was measured for length 100 mm, width 20 mm,
Attach it to one end of a 2 mm thick polypropylene plate and immediately attach it to the end of another polypropylene plate of the same size.
Overlap with an area of 0 mm x 20 mm.
A test piece was prepared by applying a load of kg / cm ² and bonding, and removing the hot melt adhesive protruding after solidification with a knife. Next, in an oven at 50 ° C., in the shearing direction of
A 200 g weight was suspended, and the time required for the bonded portion to break and drop was measured.

As is clear from Table 1, those of Examples 1 to 4 have the same low-temperature adhesiveness and excellent high-temperature adhesiveness as compared with Comparative Examples 1 to 4, or have the same high-temperature adhesiveness and low-temperature adhesiveness. Excellent adhesion.

[0049]

The hot-melt adhesive composition of the present invention comprises:
Demonstrates excellent low-temperature bonding performance and high-temperature bonding performance to polyolefin materials. According to the method for bonding a polyolefin material using the hot melt adhesive composition,
No special equipment is required, and a conventionally used coating device can be used as it is.

Claims (3)

[Claims] 1. A base polymer (a) comprising an ethylene- (meth) acrylate copolymer and / or a polyolefin resin, a tackifier resin which is liquid at room temperature, and / or
Or a tackifying resin (b) which is solid at room temperature and has compatibility with the base polymer, and a tackifying resin (c) which is solid at room temperature and is incompatible with the base polymer.
A hot melt adhesive composition comprising: 2. A tackifying resin (c) which is solid at room temperature and is incompatible with the base polymer, is 100 to 16%.
The hot melt adhesive composition according to claim 1, having a ring and ball softening temperature of 0 ° C. 3. The method according to claim 1, wherein the bonding between the polyolefin materials or between the polyolefin material and another material is performed.
A method for bonding a polyolefin material, comprising using the hot melt adhesive composition according to claim 2.