KR100297075B1 - Reactive High Temperature Melt Adhesive - Google Patents

Abstract

The present invention relates to a one-component reactive hot melt adhesive having excellent performances such as heat resistance, durability, mechanical properties, workability, and adhesion.

It is a one-component reactive hot melt adhesive consisting of a urethane prepolymer containing from 0.1 to 5% by weight of isocyanate groups. This urethane initial polymer is obtained by reacting an organic diisocyanate with an active hydrogen group-containing compound containing 1 to 100 mol% of a hydroxyl group-containing poly (ethylene-butylene) copolymer.

Description

Reactive hot melt adhesive

The present invention relates to a one-component reactive hot melt adhesive having excellent heat resistance, hydrolysis resistance, mechanical properties, adhesiveness, and the like.

Background Art Conventionally, high temperature melting type and reactive type are known for adhesives.

The hot melt adhesive is applied to the adherend by applying a hot melt adhesive to the adherend, and then adhered to the adherend, and then solidified by cooling to obtain an initial adhesive force, while having good workability, while having high adhesiveness and durability at high temperatures. There is a limit to the range of use as an adhesive due to poor.

Conventional hot melt adhesives include ethylene-vinyl acetate copolymer (EVA), low density polyethylene (LDPE), atactic polypropylene (APP), styrene-butadiene-styrene copolymer (SBS), styrene-isoprene-styrene airborne Adhesives such as copolymer (SIS), styrene-ethylene-styrene copolymer (SES), butyl rubbers, polyamides, and polyesters.

Among them, polyamide-based and polyester-based ones have relatively high heat resistance. However, since the coating temperature must be set high due to melt viscosity, they cannot be used for adherends that are weak to heat.

On the other hand, reactive adhesives are excellent in adhesive strength at high temperatures. However, generally known reactive adhesives such as epoxy and acryl are poor in workability because they have a low initial adhesive force and require a time for reaction curing.

For this reason, the reactive high temperature melt adhesive which has the initial adhesive force of a high temperature melting type | mold and the heat resistance of a reaction type | mold is examined. As the curing reaction method in this case, heating, oxidation, ultraviolet irradiation, electron beam irradiation, moisture and moisture, two-component type (topic / curing agent type) and the like have been proposed. The simplest and most practical of these is the type of adhesive that undergoes curing reaction with moisture and moisture. As this type of adhesive, reactive hot melt adhesives based on urethane initial polymers having isocyanate groups (hereinafter abbreviated as NCO groups) at the molecular ends are known.

For example, Japanese Patent Publication No. 76-47735 discloses reactive hot melt adhesives based on NCO-terminated urethane initial polymers consisting of polypropylene glycol (PPG), toluene diisocyanate (TDI), and the like. Polyurethane, whose main skeleton is polyether, is poor in heat resistance.

In addition, Japanese Patent Application Laid-Open No. 88-251415 discloses NCO group terminal urethane initials consisting of polycaprolactone polyols, polyester polyols obtained from adipic acid and hexanediol, and diphenylmethane diisocyanate (hereinafter abbreviated as MDI). Although a reactive hot melt adhesive based on a polymer has been disclosed, polyurethane based on polyester cannot be used in fields requiring hydrolysis resistance.

Japanese Patent Laid-Open Publication No. 91-207782 discloses a reactive hot melt adhesive mainly containing hydroxyl-containing isoprene, but conventional hydroxyl-containing polyolefins have a poor weather resistance due to residual double bonds and a large number of functional groups. .

An object of the present invention is to provide a one-component reactive hot melt adhesive having excellent performances such as heat resistance, durability, mechanical properties, adhesiveness, and the like.

In order to achieve the above object, the present invention provides 0.1 to 5% by weight of isocyanate groups obtained by reacting an organic diisocyanate with an active hydrogen group-containing compound containing 1 to 100 mol% of a hydroxyl group-containing poly (ethylene-butylene) copolymer. It is a 1-component reactive high temperature melt adhesive which consists of a urethane initial polymer containing.

In addition, the present invention is the adhesive having a molar ratio of ethylene group / butylene group in the hydroxyl group-containing poly (ethylene-butylene) copolymer of 30/70 to 70/30.

The hydroxyl group-containing poly (ethylene-butylene) copolymer used in the present invention is, for example, vinyl in a poly (ethylene-butylene) copolymer obtained by living polymerization of radical polymerization and anionic polymerization of ethylene and butylene. It is obtained by grafting a system alcohol compound and treating a terminal polymerization initiator component, but a random copolymer is preferable because it is the lowest in crystallinity and adhesive force.

The molar ratio of the ethylene group and the butylene group of the hydroxyl group-containing poly (ethylene-butylene) copolymer is preferably 30/70 to 70/30. If it is outside this range, since the crystallinity becomes large and melting temperature becomes high, the target reactive high temperature melt adhesive is hard to be obtained.

500-10,000 are preferable and, as for the number average molecular weight of a hydroxyl-containing poly (ethylene-butylene) copolymer, 1,000-9,000 are more preferable.

When the number-average molecular weight of the hydroxyl-containing poly (ethylene-butylene) copolymer is less than 500, the result is almost the same as that of introducing a simple chain extender into the urethane initial polymer, thereby introducing the hydroxyl-containing poly (ethylene-butylene) copolymer. One effect is difficult to obtain. In addition, when the number average molecular weight exceeds 10,000, not only the compatibility with other polyols and organic diisocyanates is low, but also the viscosity of the hydroxyl-containing poly (ethylene-butylene) copolymer becomes high. Difficult to obtain.

The hydroxyl group content of the hydroxyl-containing poly (ethylene-butylene) copolymer is preferably 1.5 to 2.5 pieces per molecule, more preferably 1.8 to 2.0 pieces, most preferably 2.0 pieces.

When the hydroxyl group is less than 1.5, the hydroxyl group-containing poly (ethylene-butylene) copolymer is less likely to be introduced into the urethane initial polymer molecule, and the terminal of the obtained urethane initial polymer is less likely to be an NCO group. The reaction is insufficient and the heat resistance and durability are inferior. When the number of hydroxyl groups is more than 2.5, gelation occurs depending on the amount of the hydroxyl group-containing poly (ethylene-butylene) copolymer when synthesizing the urethane initial polymer, making it difficult to obtain the urethane initial polymer.

Specific examples of the hydroxyl group-containing poly (ethylene-butylene) copolymer include HPVM-2202 of the Creton Liquid series manufactured by Shell, for example.

In the urethane initial polymer according to the present invention, the amount of hydroxyl group-containing poly (ethylene-butylene) copolymer is 1 to 100 mol% based on the total of the components of the active hydrogen group-containing compound.

The active hydrogen group-containing compound which can be used in the present invention may include any of those used in polyurethane chemistry other than the hydroxyl group-containing poly (ethylene-butylene) copolymer.

Specifically, for example, polymer polyols such as polyester polyols, polyether polyols, polycarbonate polyols, acrylic polyols, polyolefin polyols having a molecular weight of 500 to 10,000, more preferably 1,000 to 5,000; And polymer polyamines such as polyether polyamines; Or low molecular weight polyols having a molecular weight of less than 500, low molecular polyamines, low molecular amino alcohols used as chain extenders. In addition, NCO group regulators such as monoalcohol, monoamine and the like may be used in some cases. The active hydrogen group-containing compound may be composed of plural ones alone or in an average number of functional groups of 2 to 3, but the molecular weight of the urethane initial polymer from which the bifunctional active hydrogen group-containing compound is easily produced is preferable. These active hydrogen group-containing compounds may also contain carboxyl groups, tertiary amino groups, sulfonic acid groups, phosphoric acid groups and the like and salts thereof.

Specific examples of the polyester polyol in the polymer polyol include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4 Butanediol, neopentyl glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 2-methyl-1,5-pentanediol, 3-methyl- 1.5-pentanediol, 1,6-hexanediol, 2,2,4-trimethyl-1,3-propanediol, 2-ethyl-1,3-hexanediol, 2,2-diethyl-1,3-propane Low molecular glycols such as diol, 2-n-butyl-2-ethyl-1,3-propanediol, ethylene oxide adduct of bisphenol A, and propylene oxide adduct of bisphenol A, mixtures thereof, succinic acid, adipic acid, Polyester of both terminal hydroxyl groups obtained by dehydration condensation of dicarboxylic acid, such as sebacic acid, azelaic acid, phthalic acid, isophthalic acid, terephthalic acid, fumaric acid, maleic acid, oxalic acid, naphthylenedicarboxylic acid, and A polycaprolactone obtained by ring-opening polymerization of ε- caprolactone diol and the like.

Specific examples of the polyether polyol include polyether polyols obtained by ring-opening polymerization of one or a mixture of epoxides such as ethylene oxide and propylene oxide, or polytetramethylene glycol obtained by ring-opening polymerization of tetrahydrofuran.

As a specific example of the polycarbonate polyol, there are also those obtained by the deethanol reaction of low molecular glycols and diethyl carbonate used in the polyester polyol.

Specific examples of the polyolefin polyol include hydroxyl group-containing polybutadiene, hydroxyl group-containing hydrogenated polybutadiene, and hydroxyl group-containing polyisoprene.

As said low molecular polyol, the low molecular glycols used for the synthesis | combination of the said polyester polyol can also be illustrated.

As a low molecular polyamine, For example, Aliphatic diamines, such as ethylenediamine and hexamethylenediamine; Alicyclic diamines such as isophorone diamine and cyclohexyldiamine; And aromatic diamines such as diaminodiphenylmethane and diaminodiphenylsulfone.

Examples of the low molecular amino alcohols include monoethanol amine and diethanol amine.

Monoalcohols include methanol, ethanol, propanol, isopropanol and the like.

Moreover, as monoamine, Primary monoamines, such as ethylamine and butylamine; Secondary monoamines such as diethylamine and dibutylamine.

The organic diisocyanate used in the present invention is hexamethylene diisocyanate, lycidine diisocyanate, isophorone diisocyanate, cyclohexyl diisocyanate, 4,4'-dicyclohexyl methane diisocyanate, hydrogenated xylene diisocyanate, hydrogenated trimethyl Xylene diisocyanate, 2-methylpentane-1,5-diisocyanate, 3-methylpentane-1,5-diisocyanate, 2,2,4-trimethylhexamethylene-1,6-diisocyanate, 2,4,4 Aliphatic and alicyclic diisocyanates such as -trimethylhexamethylene-1,6-diisocyanate; 4,4'-MDI, 2,4'-MDI, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, 1,5-naphthylene diisocyanate, paraphenylene diisocyanate Aromatic diisocyanates such as tolylene-2,4-diisocyanate and tolylene-2,6-diisocyanate; Or diisocyanates which are difficult to yellow such as orthoxylene diisocyanate, methaxylene diisocyanate, paraxylene diisocyanate, tetramethylxylene diisocyanate, and mixtures thereof.

Among them, 4,4'-MDI is most preferable in terms of vapor pressure and price.

Known urethanization catalysts can be used to synthesize the urethane initial polymers according to the invention. Specific examples include organic metal compounds such as dioctyl tin dilaurate, organic amines such as triethylene amine, and salts thereof.

The urethane initial polymer according to the present invention can be synthesized by any one-shot process or two-shot process, but each raw material is formed in such a manner that a predetermined amount of NCO groups remain at the molecular end. It is necessary to react.

The NCO content of the urethane initial polymer thus obtained needs to be 0.1 to 5% by weight, with 0.5 to 4.5% by weight being preferred.

If the NCO content is less than 0.1% by weight, the molecular weight of the cured resin is increased, the melt viscosity is increased, the workability is deteriorated. Moreover, since there are few crosslinking points in resin after application | coating, sufficient heat resistance and durability cannot be obtained. When the NCO content is more than 5% by weight, the molecular weight of the cured resin becomes small and no mechanical strength is expressed.

The number average molecular weight of the urethane initial polymer according to the present invention is preferably 2,000 to 50,000, more preferably 3,000 to 20,000, most preferably 4,000 to 15,000.

If the number average molecular weight of the urethane initial polymer is less than 2,000, the mechanical strength is insufficient. If it exceeds 50,000, the melting temperature becomes too high, resulting in poor workability.

In this invention, tackifying resin can be further added and used. Such tackifying resins include terpene resins, petroleum resins, rosin resins, and terpene-phenol resins.

As a tackifier of a terpene resin, Specifically, YS resin A and YS resin Px which are a Yasuhara Chemical Co., Ltd. product; Hercules, Picclyde A, Picclyde S, and the like. Specific examples of petroleum resin tackifiers include Alcon from Kosen Kagaku Kogyo Co., Ltd., Escort from Toen Sekiyu Kagaku Co., Ltd., Hiret, Dakues, and Petro Co., Ltd. Jean. Specific examples of rosin resin tackifiers include ester gums, spa esters, and the like manufactured by Koen Chemical Co., Ltd. Specific examples of the terpene-phenol resin-based tackifiers include YS Polystar, Dieties, etc. manufactured by Yashara Chemical Co., Ltd.

Usually, it is preferable that it is 200 weight part or less with respect to 100 weight part of urethane initial polymers, and, as for the addition amount of these tackifiers, it is more preferable that it is 150 weight part or less.

In addition, in this invention, you may add and use the wax, a plasticizer, an elastomer, a stabilizer, etc. which are used for a normal hot melt adhesive agent.

The reactive hot melt adhesive of the present invention may be a plastic such as PET, nylon, polyethylene, polypropylene, etc .; Metals such as iron and aluminum; It can be adhered to all substrates such as fabric, wood, paper and the like, and is particularly effective as a polyolefin-based adhesive, which has not obtained sufficient adhesive strength with a conventional reactive hot melt adhesive.

EXAMPLE

Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these.

Example 1

A 2-liter four-necked flask equipped with a stirrer, a thermometer, an allin cooling tube, and a nitrogen gas introduction tube was used to prepare a hydroxyl group-containing poly (ethylene-butylene) copolymer (trade name: HPVM-2202, manufactured by Shell, number average molecular weight 3,600). 1778g was added and it warmed at 60 degreeC. 222g of 4,4'-MDI was put here and urethane-ized at 80 degreeC for 4 hours. After the urethanation reaction, the mixture was degassed under reduced pressure at 10 mmHg.

The NCO content of the resulting urethane initial polymer was 1.2% by weight and the viscosity of the solution was 8000cP / 100 占 폚.

Each performance test was done using this urethane initial polymer (PU-1).

These results are summarized in Table 1.

Example 2

In the same apparatus as described in Example 1, 1067 g of a hydroxyl-containing poly (ethylene-butylene) copolymer (HPVM-2202) was obtained by dehydration of 3-methyl-1,5-pentanediol and adipic acid. 711 g of both terminal hydroxyl group-containing polyesters having a number average molecular weight of 2,000 (trade name: Klapol P-2010, manufactured by Clare Co., Ltd.) were added thereto, and the mixture was heated to 60 ° C. 222 g of 4,4'-MDI was added thereto and reacted and treated in the same manner as in Example 1 to obtain a urethane initial polymer.

The urethane initial polymer had an NCO content of 0.7% by weight and a viscosity of 10000 cP / 100 占 폚.

Each performance test was done using this urethane initial polymer (PU-2).

These results are summarized in Table 1.

Example 3

In the same apparatus as described in Example 1, 667 g of hydroxyl group-containing poly (ethylene-butylene) copolymer (HPVM-2202) was obtained by dehydration of 1,6-hexanediol and adipic acid to obtain a number average molecular weight of 5,000. 1111g of both terminal hydroxyl group-containing polyester (HA-5000) was put, and it heated at 60 degreeC. 222 g of 4,4'-MDI was added thereto and reacted and treated in the same manner as in Example 1 to obtain a urethane initial polymer.

The NCO content of this urethane initial polymer was 0.9 weight%, and the viscosity of the solution was 7000 cP / 100 degreeC.

Each performance test was done using this urethane initial polymer (PU-3).

These results are summarized in Table 1.

Comparative Example 1

In the same apparatus as in Example 1, a polyester containing both terminal hydroxyl groups having a number average molecular weight of 3,000 obtained by dehydration of 3-methyl-1,5-pentanediol and adipic acid (trade name: Klapol P-3010, Kla 1778g of Leh products) were put, and it heated at 60 degreeC. 222 g of 4,4'-MDI was added thereto and reacted and treated in the same manner as in Example 1 to obtain a urethane initial polymer.

The NCO content of this urethane initial polymer was 1.2 weight%, and the viscosity of the solution was 9000 cP / 100 degreeC.

Each performance test was done using this urethane initial polymer (PU-4).

These results are summarized in Table 1.

[Performance test]

Measuring method of adhesion

The urethane initial polymers PU-1 to 4 were each applied to an aluminum plate using a hot melt applicator at a coating thickness of 50 m, and then adhered to the polypropylene plate to obtain an adhesive sample.

After the adhesive sample was allowed to stand for one week at 25 ° C. and 50% relative humidity for moisture curing, the adhesive strength was measured according to JIS K-6850.

Tensile Properties, Dynamic Viscoelasticity, Softening Method

The urethane initial polymers PU-1 to 4 were each cast to 300 μm, and then the specimen films were obtained by standing for 1 week at 25 ° C. and 50% relative humidity to cure moisture.

In the film thus obtained, its tensile properties, dynamic viscoelasticity and softening point were measured as follows.

(1) tensile properties

The film thus obtained was cut by a No. 4 single-bell cutter set in JIS K-6301, and tensile strength 200 mm / min, measurement temperature 25 deg. C, and measurement humidity 50% by Tenshiron UTM-500 (Orientech Co., Ltd.). Tensile properties (strength and elongation at break) of the film were measured.

(2) dynamic viscoelasticity

The obtained film was cut | disconnected to 4 mm x 50 mm, and the dynamic viscoelastic E 'was measured on the conditions of the frequency of 35 Hz and the temperature increase rate of 2 degree-C / min by the Leobilon (Orientech Co., Ltd. product). In addition, the glass transition temperature (Tg) was taken as the temperature where E "(loss elastic modulus) becomes the maximum. The dynamic elastic modulus E 'is a value of 25 degreeC.

(3) softening point

The obtained film was cut out by the No. 2 single-bell cutter defined by JIS-6301, and 500 kg / cm <2> was applied to the test piece film, and the temperature which the elongation rate of the test piece film triples by the temperature increase rate of 5 degree-C / min was made into the softening point.

TABLE 1

As described above, since the reactive hot melt adhesive of the present invention is a one-part type, sufficient initial adhesive force is obtained by applying the same to a to-be-adhered body after hot melting, adhering, and then cooling and solidifying. After that, the NCO group reacts and hardens with moisture in the air even without heat treatment, so it is not only excellent in workability and durability, but also excellent in heat resistance, hydrolysis resistance, and adhesiveness.

Claims (2)

In a one-component reactive hot melt adhesive composed of a urethane initial polymer obtained by reacting an active hydrogen group-containing compound with an organic diisocyanate, the active hydrogen group-containing compound may be a hydroxyl group-containing poly (ethylene-butylene) copolymer. 1 to 100 mol%, and the urethane initial polymer contains 0.1 to 5% by weight of isocyanate groups. The reactive hot melt adhesive according to claim 1, wherein the molar ratio of ethylene group / butylene group in the hydroxyl group-containing poly (ethylene-butylene) copolymer is 30/70 to 70/30.