JPH09143434A - How to use hot melt adhesive - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To provide a hot melt adhesive which can be always used in a uniform mixed state without causing the filler to settle or float even when the hot melt adhesive containing the filler is melted. Provide usage instructions. SOLUTION: Hot melt adhesive containing filler (2)
When the material is heated and melted in the melting tank 11 for use, the hot melt adhesive 2 that is heated and melted in the melting tank 11 is stirred in the melting tank 11 by using the melting tank 11 equipped with a stirrer. While taking it out, use it.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method of using a hot melt adhesive containing a filler.

[0002]

2. Description of the Related Art Hot-melt adhesives have the advantages of being solvent-free, one-pack type, and high-speed adhesiveness. They are used in the field of packaging such as cardboard boxes and carton closures, bookbinding such as book backing, and automobile parts. It is widely used in the field of product assembly such as assembling sanitary materials and building materials. When using, apply it to the adherend in the state of heating and melting, and immediately apply it.

These hot melt adhesives are composed of a base material blended with a tackifying resin, a wax, a softening agent and the like. Further, the fluidity is improved and the adhesiveness is improved.
A filler is blended for the purpose of improving heat resistance and the like.

Japanese Unexamined Patent Publication (Kokai) No. 5-194921 discloses a hot melt adhesive in which a hollow body having a volume ratio of 70 to 120% is mixed with a hot melt adhesive in order to impart a function as a foaming adhesive. Has been done.

[0005]

In the conventional hot melt adhesive containing a filler and the hot melt adhesives described in the above publications, the filler and the hot melt adhesive have different specific gravities. When the blended hot melt adhesive is left in the molten state for a long time, the filler may settle or float, the component ratio in the adhesive may change between the upper and lower parts in the melting tank, and the molten adhesive may There was a problem that the pump for supplying the gas would be clogged.

The present invention solves the above-mentioned problems of the prior art, and does not cause the filler to settle or float even when the hot-melt adhesive containing the filler is melted, so that the hot-melt adhesive is always used in a uniform mixed state. It is an object to provide a method of using a hot melt adhesive that can be used.

[0007]

The method of using the hot-melt adhesive of the present invention is such that when the hot-melt adhesive containing the filler is used, the hot-melt adhesive is melted by heating in a melting tank and equipped with a stirrer. It is characterized in that a hot melt adhesive which is heated and melted in the melting tank is taken out and used in the melting tank while being stirred by using a tank.

The hot melt adhesive as referred to in the present invention is produced by a conventionally known method, and has a composition such that a base polymer has a tackifying resin, a wax, a softening agent, a coloring agent,
It contains an antioxidant, an ultraviolet absorber, and the like.
That is, the raw materials are put into an apparatus having a heating and stirring function such as a sigma blade mixer, a ribbon mixer, a butterfly mixer, a kneader, a single-screw or twin-screw extruder, and the mixture is heated and melted and mixed at a temperature of 100 to 250 ° C. Manufactured by.

As the base polymer, ethylene- (meth) acrylic acid ester copolymer, ethylene- (meth) acrylate
Acrylic acid copolymers, ethylene- (meth) acrylic acid ester-carbon monoxide terpolymers and other ethylene-based copolymers, ethylene, propylene, 1-butene, isobutylene, 1-pentene, 1-heptene, etc. Polyolefins which are homopolymers or copolymers, the following formulas AB, ABAA,
_{(A-B) n, (} A-B) n -A, (A-B) a vinyl aromatic compound represented by the _{n + 1} X - conjugated diene (hydrogenated) block copolymer type or mixtures (although , A is a (co) polymer block of a vinyl aromatic compound such as styrene, α-methylstyrene and vinyltoluene, B is butadiene,
A block of a conjugated diene polymer such as isoprene or a hydrogenated product thereof, n is an integer of 2 or more, X is a coupling agent residue), or (meth) acrylic acid and (meth) acrylic acid ester alone Examples thereof include polymers and random or block copolymers (meth) acrylic polymers, polyamides, polyesters, nylons and polyurethanes.

Further, these base polymers are those which have been modified such as acid modification by graft polymerization of unsaturated carboxylic acid (anhydride), isocyanate groups, hydrolyzable silyl groups, vinyl groups, epoxy groups, etc. in the molecule. The curing reaction may be caused by water, an ultraviolet ray, an electron beam or the like having the reactive group of. Further, the base polymer may be composed of the same type, but may be a combination of two or more different types.

As the tackifying resin, conventionally known ones are used. Aliphatic petroleum resin, aromatic petroleum resin, alicyclic petroleum resin, aliphatic-aromatic petroleum resin, aliphatic-alicyclic petroleum resin, and fat. Aromatic-aromatic petroleum resins, coumarone-indene resins, phenol-formaldehyde resins, etc., and hydrogenated petroleum resins, rosins, polymerized rosins, disproportionated rosins, rosins such as hydrogenated rosins, rosins And ethylene glycol, diene glycol, glycerin, rosin esters which are esters of pentaerythritol and the like, terpene resins such as polyterpene resin, terpene-phenol resin, terpene-styrene resin, and the like,
These may be used alone or in combination of two or more.

As the wax, those used for ordinary hot melt adhesives can be used as they are, and paraffin wax, polyethylene wax, microcrystalline wax, Fischer-Tropsch wax, etc., and unsaturated carboxylic acid (anhydride) are grafted onto these waxes. Examples thereof include polymerized acid-modified wax and oxidized wax. Further, it may be one which causes a curing reaction by moisture, ultraviolet rays, electron beams or the like having a reactive group such as an isocyanate group, a hydrolyzable silyl group, a vinyl group or an epoxy group in the molecule. These waxes may be used alone or in combination of two or more.

As softening agents, process oils known as rubber developing oils such as paraffin oil, naphthene oil and aroma oil, plasticizers such as phthalic acid ester and phosphoric acid ester, liquid polybutene, liquid polybutadiene and Examples thereof include hydrogenated products thereof, liquid polyisoprene and hydrogenated products thereof. These may be alone,
Two or more types may be used in combination.

As the antioxidant, known antioxidants such as hindered phenol type, phosphorus type and sulfur type may be used alone or in combination of two or more kinds. As other additives, colorants such as pigments and dyes, ultraviolet absorbers, curing reaction catalysts and the like can be added depending on the purpose.

The present invention is directed to the above-mentioned hot melt adhesive compounded with a filler. As the filler, those having a specific gravity of more than 1 such as calcium carbonate, clay, talc, carbon black, silica, benton, and chalk are generally used, and those having a specific gravity of less than 1 include:
For example, there may be mentioned micro hollow bodies known as "balloons" in the field of fillers. Materials for forming the balloon include inorganic materials such as shirasu, perlite, glass, fly ash, alumina, zirconia, and carbon, and organic materials such as phenol resin, epoxy resin, urea resin, saran resin, polystyrene, polymethacrylate, and polyacrylonitrile. You can list the following. Further, a composite balloon in which the surface of an organic balloon is coated with an inorganic material, or a porous filler can also be used. Further, it may be surface-treated with a silane coupling agent or the like.

The mixing amount of the filler with respect to the hot melt adhesive is not particularly limited, but is generally 5 to 300 parts by weight with respect to 100 parts by weight of the hot melt adhesive, and the application,
It may be appropriately selected depending on the desired performance.

As a means for stirring the molten hot melt adhesive containing a filler in the melting tank, a stirring blade is installed in the melting tank to stir the hot melt adhesive in the tank. is there. There are propeller shape, meniscus shape, plate shape, ribbon blade, etc. as the shape of the stirring blade, and the stirring method is by rotating around the axis, moving up and down, left and right, or a combination of these. Is mentioned. Examples of such devices include, for example, Nordson,
Applicators commercially available from Suntool Co., ITW Dynatec Co., Iwata Coating Machine Co., etc. can be used.

As another means for stirring, a circulation pump is arranged outside the melting tank, and the adhesive returns to the inside of the melting tank again via a pump and a hose provided outside the melting tank. Then, there is a method of stirring by the flow of the inflowing adhesive. The pump used here may be of a type generally used as a liquid transport pump, such as a gear pump, a screw pump, a snake pump, a plunger pump, or the like.

Further, using a commercially available applicator model equipped with two or more pumps, one of them is used for circulation, and the hot melt adhesive is transferred from the other end of the heating hose attached to the discharge port to the melting tank. A method of returning can also be adopted. The hot melt adhesive circulation path is preferably such that the outlet and inlet are located opposite the tank, such as exiting the bottom of the melting tank and returning to the top of the tank, or vice versa. However, it is not particularly limited.

(Function) Even if fillers having different specific gravities are blended with the hot melt adhesive, the fillers do not settle or float in the molten state because they are stirred in the molten state in the melting tank. As a result, it can always be used in a homogeneous mixed state. Further, the pump for supplying the molten adhesive does not become clogged.

[0021]

Next, embodiments of the present invention will be described. (Example) The following composition was heated and mixed at 180 ° C to prepare a hot melt adhesive. Base polymer: ethylene-vinyl acetate copolymer (manufactured by Mitsui DuPont Polychemical Co., Ltd., trade name "Eva Flex 210") 40 parts by weight Tackifying resin: rosin ester (manufactured by Arakawa Chemical Co., Ltd., trade name "Super Ester A-115") 40 parts by weight Paraffin wax: (manufactured by Nippon Seiro Co., Ltd., trade name "paraffin wax 155") 20 parts by weight Filler: silica balloon (manufactured by Asahi Glass Co., Ltd., trade name "Q-CEL600") 10 parts by weight Stabilizer: 1 part by weight of a hindered phenolic antioxidant (manufactured by Ciba-Geigy, trade name “Irganox 1010”) The amount of the filler in this composition was 9.0% by weight.

Hot melt applicator 1 shown in FIG.
(Nordson, product number "HM3400")
After heating 4 kg of the hot melt adhesive 2 at 180 ° C. to completely melt it, the tip of the heating hose 4 connected to the discharge port of the pump 3 is placed on the melting tank 11, and 0.3 kg / It was discharged at a rate of min and circulated so as to return from the tip of the heating hose 4 to the melting tank 11 again. This was continuously performed for 12 hours.

Thereafter, 100 g of the hot melt adhesive discharged from the tip of the supply hose 6 was first discarded, and 100 g of the hot melt adhesive that subsequently came out was sampled to obtain "Discharge 1". Further, 100 g after discharging 3.5 kg from the tip of the supply hose 6 was designated as "Discharged product 2".

Tetrahydrofuran 500
Dissolved in g, the insoluble filler was collected, and the weight fraction of the discharged product was determined.
The amount of the filler in each is 8.9% by weight and 9.1% by weight, which is almost the same as the amount of the filler in the original hot melt adhesive, and the separation of the filler is prevented by circulating the adhesive. It was clear that it was done.

(Comparative Example) The same operation as in Example was carried out except that heating was performed for 12 hours without circulating the adhesive with a pump. As a result, the amounts of the fillers in the discharge products 1 and 2 were 5.2% by weight and 12.1% by weight, respectively, and it was found that the filler having a low specific gravity had risen to the upper portion of the melting tank.

[0026]

By melting and circulating the hot melt adhesive in the melting tank, separation of the filler due to settling or floating is prevented, and the adhesive composition can be used even after heating for a long time without change. Further, troubles such as clogging of the coating nozzle due to agglomeration of the filler can be prevented in advance.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for explaining an example of a method of using a hot melt adhesive according to the present invention.

[Explanation of symbols]

 1: Hot melt applicator 2: Hot melt adhesive 3: Pump 4: Heating hose 5: Heating part 6: Supply hose 11: Melting tank

Claims (1)

[Claims] 1. A hot melt that is heated and melted in a melting tank using a melting tank equipped with a stirrer when heating and melting in a melting tank to use a hot melt adhesive containing a filler. A method of using a hot melt adhesive, characterized in that the adhesive is taken out and used in the melting tank while being stirred.