JPH02178383A - Hot-melt adhesive composition - Google Patents

Abstract

PURPOSE:To obtain the title composition containing a polyurethanepoloyisocyanate prepolymer, rosin ester and silane coupling agent at a specific ratio, having water resistance and heat resistance and remarkably improved especially in adhesion with metals. CONSTITUTION:The aimed composition consisting of (A) 40-90 pts.wt. polyurethanepolyisocyanate prepolymer obtained by copolymerizing a polyol having a carboxyl group bonded through an ester linkage to main chain, (B) 10-60 pts.wt. rosin ester, preferably having <=110 deg.C thermosetting temperature and <=10 acid value and (C) 0.1-10 pts.wt. mercaptan-based silane coupling agent, preferably having silanol group and mercaptan group.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a one-component moisture-curing hot melt adhesive used for building materials, furniture, textile products, vehicles and vehicle parts, etc.

[Prior Art] A hot melt adhesive is a solvent-free adhesive that is solid at room temperature, and is used as a liquid by heating and melting. This adhesive is easy to use, has a fast adhesion speed, provides strong adhesive force immediately after processing, and has good workability.

[Problems to be Solved by the Invention] Hot melt adhesives that have been commonly used have a fatal drawback of poor heat resistance.

Polyurethane adhesives are used in various industrial fields, but because they lack adhesion to metal surfaces (especially after immersion in water), they are significantly less effective against constituent materials such as aluminum foil and steel plates. Usage is restricted.

The present inventors aimed to solve the above-mentioned deficiencies of the prior art, and first of all, the present inventors developed a method that can repeatedly use hot melt at a relatively low temperature of around 100°C, has a heat resistance of 150°C or more after curing, and has a metal surface. As a result of extensive research in order to obtain a one-component moisture-curing hot melt adhesive that also has adhesive strength with The present invention was achieved by discovering that an adhesive obtained by melt-mixing a polymer and rosin ester in a specific ratio and further mixing a silane coupling agent has excellent adhesive properties, water resistance, and heat resistance. .

[Means for Solving the Problems] That is, the present invention provides a polyurethane polyisocyanate prepolymer 4 obtained by copolymerizing a polyol having a carboxyl group bonded to the main chain via an ester bond.
0 to 90 parts by weight, 10 to 60 parts by weight of rosin ester, and 0.1 to 10 parts by weight of a silane coupling agent.

Next, to explain the present invention in more detail, the silane coupling agent used in the present invention is a mercaptan-based polymer having a mercapto group as an organic functional group and a silanol group as a hydrolyzable group reactive with inorganic materials. The use of this silane coupling agent significantly improves the adhesion to metals, which conventional polyurethane adhesives are weak at.

Specific examples of mercaptan-based V run coupling agents include γ-mercaptoglobil trimethoxysilane,
γ-Mercaptogropylmethyldimethoxysilane, γ-
Examples include mercagutoglopyrudimethylmethoxysilane and γ-mercagutoglopyruethyldimethoxysilane.

The blending amount of the silane coupling agent is 01 parts by weight to 10 parts by weight, preferably 0.5 parts by weight to 5 parts by weight. 0.
If it is less than 1 part by weight, a sufficient effect cannot be obtained, and if it is more than 10 parts by weight, a large amount of water is required when the silane coupling agent is hydrolyzed into silanol, which may result in poor curing. do not have.

I bonded to the main chain via an ester bond used in the present invention
;Polyols having carboxyl groups are polyols having trifunctional or more functional hydroxyl groups, various polycarboxylic acids,
Preferably, it is obtained by reacting a polycarboxylic acid having an acid anhydride group in the molecule so that at least two hydroxyl groups of the polyol remain.

Preferred polyols include trihydric or higher alcohols such as glycerin, diglycerin, polyglycerin, erythritol, pentaerythritol, arabitol, sorbitol, sorbitan, mannitol, mannitan, trimethylolpropane, or ethylene oxide using these alcohols as an initiator. Polyether polyols obtained by polymerizing alkylene oxides such as propylene oxide and butylene oxide, polyester polyols having trivalent or higher hydroxyl groups consisting of these polyhydric alcohols or polyether polyols, and dicarboxylic acids; Examples include a polymer of alkylene oxide, a polyester polyol containing trivalent or higher hydroxyl groups obtained from the polymer and dicarboxylic acid, and the like. In the present invention, particularly preferred among these polyols are polyether triols and polycaprolactone triols having a molecular weight of about 90 to 4,000.

Further, as the polycarboxylic acid to be reacted with the above polyol, any polycarboxylic acid having two or more carboxyl groups can be used, and preferred examples include oxalic acid, malonic acid, succinic acid, and glutaric acid. Acid, adipic acid, pimelic acid, speric acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, methylmaleic acid, methyl hexamalic acid, itaconic acid, citraconic acid,
Mesaconic acid, acetylenic acid, malic acid, methylmalic acid, citric acid, incitric acid, tartaric acid, heptalatric acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, naphthalene dicarboxylic acid and their alkyl esters, acid halogens Among the above-mentioned polycarboxylic acids, acid anhydrides which can have an acid anhydride group are most preferred in the present invention.

The reaction between the polyol as described above and the polycarboxylic acid as described above is preferably carried out at a ratio in which the obtained carboxylic acid-modified polyol becomes a diol, for example, at a ratio of 1 mol of dicarboxylic acid anhydride to 1 mol of triol. .

The reaction between a polyol and a polycarboxylic acid, especially an acid anhydride of a polycarboxylic acid, is extremely easy and can be carried out according to a conventional method. Alternatively, it may be performed after manufacturing. Most preferably, the polyol is modified with carboxylic acid in advance before producing the polyurethane resin.

The polyurethane polyisocyanate prepolymer obtained by copolymerizing a polyol having a carboxyl group bonded to the main chain via an ester bond used in the present invention is prepared by combining a polyol and an organic polyisocyanate compound in a conventional manner at an N G Olo H ratio of 1. It can be easily obtained by reacting at .1 or more and using a small amount of chain extender if necessary.

In addition, in the present invention, as the polyol used in combination with the polyol having a carboxyl group described above, conventionally known polyols that can be used in normal polyurethane production can be used alone or in a mixture of two or more types.

Preferred examples of such conventionally known polyols include those whose terminal group is a hydroxyl group and whose molecular weight is 300 to 300.
4000 polyethylene adipate, polyethylene propylene adipate, polyethylene butylene adipate,
polydiethylene adipate, polybutylene adipate,
Polyethylene succinate, polybutylene succinate, polyethylene sebacate, polybutylene sebacate,
Polytetramethylene ether glycol, poly-ε-caprolactoneol, polyhexamethylene abate, carbonate polyol, polyethylene glycol,
Examples include polypropylene glycol.

The organic polyisocyanate used in the present invention is
It is a compound having at least two incyanate groups in an aliphatic or aromatic compound, and has been widely used as a synthetic raw material for polyurethane resins.

Any of these known organic polyisocyanates are useful in the present invention. Particularly preferred organic polyisocyanates are as follows.

Tolylene diisocyanate, 4-methoxy-1,3-7
22 diisocyanate, 4-isopropyl-1,3
-phenylene diisocyanate, 4-chloro-1,3-
Phenyl diisocyanate, 4-butoxy-1,3-
Finidine diisocyanate, 2,4-diisocyanate-diphenyl ether, mesitylene diisocyanate, 4.4°-methylenebis(phenylisocyanate)
, shrylene diisocyanate, 1.5-su7thalene diisocyanate, benzidine diisocyanate, O-
Nitropenzidine diisocyanate-1-14,4-diisocyanate dibenzyl, 1,4-tetramethylene diisocyanate, 1,6-titramethylene diisocyanate, 1.10-decamethylene diisocyanate, 1. 4-
Ncrohexyl diiso/anate, quinolone diisocyanate, 4,4-methylenebis(ncrohexylisona-h), 1,5-tetrahydronaphthalene diisocyanate, inphorone diisocyanate, etc.

Further, chain extenders that may be used in the present invention include ethylene glycol, propylene glycol, diethylene glycol, 1.4-7'tanediol, 1.6-hexanediol, water, and the like.

Although it is not always necessary to mix a small amount of isone anate adduct with these polyurethane polyisocyanates, it is effective for increasing the crosslinking density.

The rosin ester used in the present invention is a polyhydric alcohol ester of rosin, that is, mainly abietic acid and/or its hydrogenated product, and preferred examples of the polyhydric alcohol include glycerin pentaerythritol, diethylene glycol, and triethylene glycol.

If the amount of rosin ester added is 60 parts or more, sufficient heat resistance cannot be obtained, and if the amount is less than 10 parts, initial adhesive strength cannot be obtained.

Also, if its acid value is high, it will inhibit the curing of the inner layer,
This is not preferable because crosslinking due to moisture becomes insufficient.

(Function) In the adhesive composition of the present invention, the polyisocyanate prepolymer is post-crosslinked by moisture in the air, and curing is accelerated to obtain excellent heat resistance, and the polyisocyanate prepolymer is bonded to the main chain through ester bonds. The bonded carboxyl group and the silanol group of the 7-run coupling agent provide adhesive strength to the metal surface.

It is also believed that the action of the rosin ester imparts hot-melt properties and adhesiveness at the same time as heat resistance.

Furthermore, a reaction occurs between the residual hydroxyl groups of the rosin ester and the terminal isocyanate groups of the prepolymer, and the resulting reaction product acts as a compatibilizer for both the polyurethane polyisomer and the rosin ester. Therefore, the entire adhesive composition exhibits behavior similar to a homogeneous system, and it is thought that the one-component suitability is exhibited synergistically.

Hereinafter, the present invention will be specifically explained with reference to Examples.

[Example] Example 1 1000 parts by weight of ethylene oxide adduct of trimethylolpropane (molecule 1 about 1000) and 140 parts by weight of phthalic anhydride were placed in 21 flasks equipped with a nitrogen inlet tube, a thermometer, a stirrer, and a distillation tube. and 57 parts by weight of methyl ethyl ketone were charged, and the temperature was raised to 150 to 160°C in 1 hour and 30 minutes.
The reaction was further continued for 1 hour and 30 minutes at a temperature of 150 to 16 Q'C. Thereafter, the pressure inside the container was reduced to 5 to 19 rom ml to remove the solvent and unreacted substances, thereby obtaining carboxyl group-modified polyethylene diol.

This product had a hydroxyl value of 92 and an acid value of 45.

The above carboxyl group-modified polyethylene diol 100
Part by weight, polypropylene diol with a hydroxyl value of 112 80
0 parts by weight, 361 parts by weight of MI)1 are reacted at 90 DEG C. for 9 hours to obtain a polyisocyanate prepolymer having an NCO content of 2.8%.

Furthermore, rosin ester (product name: Ester Gum HP)
, pentaerythritol ester of hydrogenated rosin manufactured by Marukaku Kagaku Kogyo Co., Ltd.) 8001i parts and a silane coupling agent (
70 parts by weight (trade name: KBM-803, manufactured by Shin-Etsu Chemical Co., Ltd.) were added thereto and stirred and mixed at 95° C. for 1 hour to obtain a hot melt adhesive composition with an NCO content of 1.4%.

Comparative Example 1 1000 parts by weight of ethylene oxide adduct of trimethylolpropane (molecule 1 about 1000), 140 parts by weight of phthalic anhydride, and 57 parts by weight of methyl ethyl ketone were placed in 21 flasks equipped with a nitrogen inlet tube, a thermometer, a stirrer, and a distillation tube. 1 hour and 30 minutes to raise the temperature to 150-160℃,
Further, the reaction was carried out for 1 hour and 30 minutes at a temperature of 150 to 160°C. Thereafter, the pressure inside the container was reduced to 5 to 10 mmHy to remove the solvent and unreacted substances to obtain carboxyl group-modified polyethylene diol.

The hydroxyl value of this product is 92, and the acid value is 45.
two.

The above carboxyl group-modified polyethylene diol 100
Part by weight, polypropylene diol with a hydroxyl value of 112 80
0 parts by weight of MDI and 361 parts by weight of MDI were reacted at 90° C. for 9 hours to obtain a polyisocyanate prepolymer having an NCO content of 2.8%.

Comparative Example 2 1000 parts by weight of polypropylene diol having a hydroxyl value of 112 and 375 parts by weight of MDI were reacted at 90° C. for 8 hours to obtain a polyisocyanate prepolymer having an NGO content of 3.0%.

Further, 600 parts by weight of the same rosin ester as in Example 1 was added thereto, and the mixture was stirred and mixed at 95°C for 1 hour, until the NCO content was 1.
A 6% hot melt adhesive composition was obtained.

Example 2 1000 parts by weight of caprolactone adduct of trimethylolpropane (molecule 1 about 850), 220 parts by weight of trimellitic anhydride and 61 parts by weight of toluene were placed in 21 flasks equipped with a nitrogen inlet tube, a thermometer, a stirrer and a distillation tube. prepare the department,
The temperature was raised to 150-160℃ in 1 hour and 30 minutes, and then further heated to 150℃.
The reaction was carried out for 1 hour and 30 minutes at a temperature of ~160°C. after that,
The pressure inside the container was reduced to 5 to lo+++Ill[ig to remove the solvent and unreacted substances, and a carboxyl group-modified polycaprolactone diol was obtained.

This product had a hydroxyl value of 106 and an acid value of 53.

100 parts by weight of the aforementioned carboxyl group-modified polycaprolactone diol, 900 parts by weight of polyvalerolactone diol with a hydroxyl value of 56, and 3 parts by weight of XD1153 were mixed at 90'C! The reaction was carried out for 9 hours to obtain a polyisocyanate prepolymer having an NCO content of 1.9%.

Furthermore, rosin ester (product name: Ester Gum HP)
, 800 parts by weight of hydrogenated rosin pentaerythritol ester (manufactured by Marukaku Kagaku Kogyo Co., Ltd.) and 35 parts by weight of a silane cuff pulling agent (trade name: TSL-8380, manufactured by Tobu/Ricone Co., Ltd.), and heated at 95°C for 1 hour and 30 minutes. Stir to mix, NGO
A hot melt adhesive composition with a content of 0.9% was obtained.

Comparative Example 3 1000 parts by weight of polyvalerolactone diol having a hydroxyl value of 56 and 188 parts by weight of XDI were reacted at 90°C for 8 hours to obtain a polyisocyanate prepolymer having an NCO content of 1.7%.

Further, 600 parts by weight of the same rosin ester as in Example 2 was added thereto, and the mixture was stirred and mixed at 95° C. for 1 hour to obtain a hot melt adhesive composition with an NCO content of 1.0%.

Example 3 Propylene oxide adduct of glycerin (molecule 1 approx. 1
500) 1000 parts by weight, 100 parts by weight of carboxyl-modified polypropylene diol (hydroxyl value 69, acid value 35) obtained by reacting 67 parts by weight of conolic acid anhydride, 900 parts by weight of polyethylene glyfur with a hydroxyl value 112,
250 parts by weight of TDI are reacted at 90'O for 8 hours to obtain a polyinsyanate prepolymer with an NGO content of 2.9%.

Furthermore, rosin ester (trade name: two ester gum AA) is added to this.
V, rosin glycerin ester manufactured by Marukaku Kagaku Kogyo Co., Ltd.) 7
50 parts by weight and Nran coupling agent (trade name: 5H-
Add 30 parts by weight of 6062 (manufactured by Toshi Silicon Co., Ltd.), and add 95
Stirring and mixing were carried out at .degree. C. for 1 hour to obtain a hot melt adhesive composition with an NGO content of 1.5%.

Comparative Example 4 1000 parts by weight of polypropylene glycol having a hydroxyl value of 112 and 260 parts by weight of TDI were reacted at 90° C. for 8 hours to obtain a polyisocyanate prepolymer having an NGO content of 2.9%.

Comparative Example 5 750 parts by weight of rosin ester (trade name: Ester Gum AAV, glycerin ester of rosin manufactured by Marukaku Kagaku Kogyo Co., Ltd.) was added to the prepolymer of Comparative Example 4, and the mixture was stirred and mixed at 95° C. for 1 hour to obtain an NGO content of 1. A .7% hot melt adhesive composition was obtained.

Comparative Example 6 Commercially available hot melt adhesive (product name: Asahi Melt C-
1300, manufactured by Asahi Kagakusei Co., Ltd.).

Using the compositions of Examples 1 to 3, Comparative Examples 1 to 5, and the hot melt adhesive of Comparative Example 6, a degreased iron plate (1 mm thick) was prepared.
and plywood (4 mm thick) were bonded together, and the initial adhesive strength was measured after 30 minutes at room temperature according to the provisions of JIS K6850, tensile shear adhesive strength measuring method.

In addition, the heat resistance after 10 days at room temperature was tested in accordance with JISK-6829 Automotive Adhesive Test Method Section 13A, Heat Softening Temperature Measuring Method Standard, and Table 1 shows the results.

Note that room temperature here refers to JIS standard condition class 3, humidity 65.
±20% (JIS Z-8703).

(Left below) *Surface damage to plywood [Effects of the invention] The adhesive of the present invention has good hot melt properties, tackiness, and adhesion to metal surfaces, and is excellent in heat resistance, and is liquid-based. It is also excellent in terms of workability. Therefore, it can be effectively applied in a wide range of fields, such as the automobile industry, the construction industry, the electronic parts field, the food industry, the medical industry, and the textile processing field.

Patent applicant: Dainichiseika Industrial Co., Ltd.

Claims (1)

[Scope of Claims] 1. 40 to 90 parts by weight of a polyurethane polyisocyanate prepolymer obtained by copolymerizing a polyol having a carboxyl group bonded to the main chain via an ester bond,
A hot melt adhesive composition comprising 10 to 60 parts by weight of a rosin ester and 0.1 to 10 parts by weight of a silane coupling agent. 2 Rosin ester has a heat softening temperature of 110°C or less and an acid value of 1
The hot melt adhesive composition according to claim 1, wherein the hot melt adhesive composition is 0 or less. 3. The hot melt adhesive composition according to claim 1, wherein the silane coupling agent is a mercaptan-based silane coupling agent having a silanol group and a mercaptan group.