JPH02107687A - hot melt adhesive composition - Google Patents

Abstract

PURPOSE:To obtain the subject readily usable composition, containing a polyurethane polyisocyanate prepolymer and a rosin ester at a specific ratio, having a high bonding rate and capable of providing a powerful adhesive strength from just after processing with good operability. CONSTITUTION:A one-pack type moisture curing type hot-melt adhesive composition consisting of (A) 40-90pts.wt. polyurethane polyisocyanate prepolymer, obtained by reacting a polyol having preferably >=700 average molecular weight with an organic diisocyanate and having <=6% NCO content and (B) 60-10pts.wt. rosin ester having preferably <=110 deg.C heat softening temperature and <=10 acid value. The above-mentioned composition is used as building materials, furniture, fibers, vehicles and books, etc.

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, textiles, vehicles, books, 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.

Therefore, in applications where heat resistance is generally required, two-component curing adhesives have had to be used at the expense of workability, such as temporary fixing.

The present inventors aimed to solve the above-mentioned defects of the prior art, and first of all, the present inventors developed a product that can be repeatedly used as a real melt at a relatively low temperature of around 1006°C, and has heat resistance of 150°C or more after curing. As a result of extensive research to obtain a liquid-curing honodomelt adhesive, we discovered that an adhesive obtained by melt-mixing polyurethane polyinsyanate prepolymer and rosin ester in a specific ratio has excellent heat resistance. We have arrived at the present invention.

[Means for Solving the Problems] That is, the present invention provides 40 to 90 parts by weight of polyurethane polyisocyanate brepolymer and 60 to 60 parts by weight of rosin ester.
10 parts by weight of a one-component moisture-curable true melt adhesive composition.

To explain the present invention in more detail, the present invention combines a polyol and an organic diisocyano-I- with a N G Olo H ratio of 1.1.
This is a one-component moisture-curable hot melt adhesive made by reacting the above to obtain a polyurethane polyisocyanate prepolymer and melt-mixing the rosin ester.

The polyurethane polyisocyanate prepolymer used in the present invention can be easily prepared by reacting a polyol and an organic polyisocyanate compound at an N COlo H ratio of 1.1 or more according to a conventional method, and also using a small amount of a chain extender if necessary. can be obtained.

As the polyol used in the present invention, conventionally known polyols that can be used in ordinary polyurethane production can be used alone or in combination.

Preferred examples of such conventionally known polyols include those whose terminal group is a hydroxyl group and whose molecular weight is 700 to 700.
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 adipate,
There are carbonate polyols, polyethylene glycols, polypropylene glycols, etc.

It is necessary that the molecular weight of the polyol is 700 or more. The reason why the molecular weight of polyol is limited is that when a low molecular weight polyol is used, the resulting polyisocyanate inevitably has a high NGO content, which requires a large amount of moisture for curing, which impairs the reliability of curing. Easy to fall.

Further, carbon dioxide gas is generated due to the reaction between NCO/H20, or if the amount exceeds a certain level, intralayer defects are caused in the adhesive layer.

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-
Phenyl diisocyanate, 4-chloro-1,3-7
22 diisocyanate, 4-butquine-1,3-7
, r, nylene diisocyanate, 2,4-diincyanate diphenyl ether, mesitylene diisocyanate
1., 4.4'-methylene bis(phenylisocyanate), shurylene diisocyanate, 1.5-su7thalene diisocyanate, penzidine diisonanate, 0
-Nitrobenzidine diisocyanate, 4.4-dibenzyl diisocyanate, 1.4-tetramethylene diisocyanate, 1.6-tetramethylene diisocyanate, 1.10-decamethylene diisocyanate, 1.4-
cyclohexylene diisocyanate, xylylene diisocyanate, 4,4-methylenebis(cyclohexyl isocyanate), i,s tetrahydronaphthalene diisocyanate, isophorone diisocyanate, and the like.

Further, chain extenders that may be used in the present invention include ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, 1,6-hexanediol, water, and the like.

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

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

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.

In addition, its high acid value inhibits the curing of incyanate,
This is not preferable because crosslinking due to moisture becomes insufficient.

(Function) In the adhesive composition of the present invention, the polyurethane polyisocyanate prepolymer is post-crosslinked by moisture in the air, accelerating curing and providing excellent heat resistance. 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 polyurethane, and the resulting reaction product acts as a compatibilizer for both the polyurethane polyester and the rosin ester. Because of this effect, the adhesive composition as a whole exhibits behavior similar to that of a homogeneous system, and it is thought that the one-component suitability is synergistically promoted.

This will be explained in more detail below with reference to Examples.

[Example 1 Example 1 600 g of PEG with an average molecular weight of 1000 and a hydroxyl value of 112
and TD I I 9 B9 were reacted at 80° C. for 8 hours under a nitrogen stream to obtain polyurethane Polyson-A-1- (Comparative Example 1) with an NGO content of 5.4%.

Furthermore, ester gum AAV (manufactured by Kanyo Kagaku Kogyo Co., Ltd., glycerin ester of rosin) 50J) was added to this, and the mixture was heated at 95°C.
Stir and mix for 1 hour. h' c o of the resulting composition
The content rate was 3.0%.

Example 2 1000g of valerolactone polyol having an average molecular weight of 2000 and a hydroxyl value of 56 was reacted with 2sog of MDI at 80°C for 6 hours under a nitrogen stream to obtain a polyurethane polyisocyanate (Comparative Example 2) with an NGO content of 3.1%. Furthermore, 800 g of Ester Gum HP (manufactured by Kanyo Kagaku Kogyo, pentaerythritol ester of hydrogenated rosin) was added to this,
Stir and mix at 90°C for 1 hour. NGO of the resulting composition
The content was 1.7%.

Example 3 Average molecular weight 2000. 600g of PEG with a hydroxyl value of 56,
100 g of caprolactone polyol with an average molecular weight of 850 and a hydroxyl value of 195 and XDI2349 were mixed with
The reaction was carried out at °C for 10 hours to obtain a polyurethane polyol (Comparative Example 3) with an N GO content of 3.9%. Furthermore, Ester Gum H3 (manufactured by Kanyo Kagaku Kogyo Co., Ltd., glycerin ester of modified Logi) 8009 was added to this, and the mixture was stirred and mixed at 90°C for 1 hour. The NGO content of the resulting composition was 2.2
%Met.

Examples 1 to 3 The compositions of Comparative Examples 1 to 3 and a commercially available hot/melt adhesive: Asagae Melt C-1300, a product of Asahi Kagakusei Co., Ltd. (Comparative Example 4), were used as a hot melt adhesive, and a degreased iron plate was used. 1mm and a 9mm Styrofoam board were bonded together, and the initial adhesion strength after 30 minutes at room temperature was determined according to JISK-68.
50, according to the provisions of the tensile shear adhesive strength measurement method,
In addition, the heat resistance after 10 days at room temperature was tested in accordance with the specifications of Section 13A of Heat Softening Temperature Measurement Method of JrSK-6829 Automotive Adhesive Test Method, and the results are shown in Table 1. It can be seen that a true melt adhesive composition can be obtained.

In addition, room temperature here is JIS standard standard condition 3 eaves temperature 0 ± 5°C
1 Humidity is 65±20%. (Z (hereinafter referred to as blank space) [Effects of the invention] The adhesive of the present invention has good hot-melt properties and adhesive properties, and is excellent in heat resistance. Also, since it is a liquid type, 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)

[Claims] 1. Polyurethane polyisocyanate prepolymer 40
A hot melt adhesive composition comprising ~90 parts by weight and 60-10 parts by weight of a rosin ester. 2 The polyurethane polyisocyanate prepolymer is
The composition according to claim 1, which is a prepolymer with an NCO content of 6% or less obtained by reacting a polyol with an average molecular weight of 700 or more and an organic diisocyanate. 3 Rosin ester has a heat softening temperature of 110°C or less and an acid value of 1
0 or less.