JP2002188073A - Fusion-bondable adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fusion-bondable adhesive capable of being produced from easily available raw materials, capable of enabling rapid curing and rapid drying, and also capable of providing sufficient adhesive strength. SOLUTION: This fusion-bondable adhesive comprising a polyisocyanate and a polyester polyol is characterized in that the adhesive contains a crystalline polyester polyol obtained from an aliphatic hydrocarbon diol comprising 1,10- decanediol and/or 1,12-dodecanediol, and a polybasic carboxylic acid, and having 1,500-15,000 number average molecular weight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a melt adhesive comprising a polyisocyanate and a polyester polyol, comprising a 1,10-decanediol and / or 1,12-decanediol.
-Obtained from an aliphatic hydrocarbon diol containing dodecanediol and a polycarboxylic acid, having a number average molecular weight of 1500
To 15,000 crystalline polyester polyols. The molten adhesive of the present invention has an extremely short adhesive time and excellent adhesive strength, and is used for various applications as an adhesive.

[0002]

2. Description of the Related Art Polyester is a compound well known in the industry, and various compounds are used. In particular, polyester polyols can be cross-linked and cured by various cross-linking agents, for example, isocyanate compounds, and are widely used as paints, adhesives, inks and sealants. Of these, crystalline polyester polyols are:
In addition to its excellent mechanical properties, it can be treated as a relatively low-viscosity liquid at temperatures above its melting point, and has the property of solidifying in a short time for recrystallization when cooled below the crystallization temperature. . Due to this characteristic, use as a component of a reactive hot melt adhesive or an inkjet ink for hot melt is expanding. In particular, reactive hot-melt adhesives have excellent strength and bonding speed, have high suitability for line production in the assembly industry, and are rapidly growing to meet the social demands for solvent removal and energy saving. ing. At the same time, there is a strong demand for improvement in continuous workability, and there is a demand for a reactive hot melt adhesive having a faster curing rate. To meet this demand, a combination of a reactive hot melt adhesive with an adhesive resin or a thermoplastic polymer is being studied. For example, EP-A-0232055 combines an ethylene / vinyl acetate comonomer or a methylstyrene resin with EP-A-024.
No. 6473, it is combined with an acrylate oligomer. However, such reactive hot melt adhesives still contain a high proportion of thermoplastic resin after crosslinking and curing, and a reduction in shear strength at high temperatures is inevitable. On the other hand, European Patent Application Publication No. 0248658 discloses a polyester hot-melt adhesive using an aromatic dicarboxylic acid. If you use aromatic polyester,
Although the heat resistance is improved, the viscosity at the time of melting is too high,
There is a drawback that workability during coating is significantly reduced.

[0003] Conventionally, as a raw material of a polyester polyol used for a reactive hot melt adhesive, terephthalic acid, isophthalic acid,
The diol component such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, etc. includes ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, , 4-cyclohexanedimethanol and the like are known.

[0004] On the other hand, the fact that the degree of crystallinity of a polyester polyol affects its curing rate is described in Adhesion, 1984,
Vol. 28, No. 8, page 5 and ADHESIVES AGE, 1987, November, 32
This is a known fact as described on the page, that is, a polyester polyol having a high crystallinity is extremely advantageous for improving the curing rate. Among the polyester polyols obtained from the combination of the above monomers, for example, JP-A-2-88686 discloses that dodecanedioic acid and 1,6 are used as raw materials for producing a reactive hot melt adhesive having an improved curing rate. Those using -hexanediol, those using sebacic acid and 1,6-hexanediol, polyester polyols using dodecanedioic acid and ethylene glycol, and the like have been disclosed. The combination of is no longer able to meet.

[0005]

DISCLOSURE OF THE INVENTION The present invention can be manufactured from readily available raw materials, enables quick curing and quick drying,
It is an object of the present invention to provide a molten adhesive which sufficiently provides an adhesive strength.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, it has been found that a molten adhesive comprising a polyisocyanate and a polyester polyol has 1,10-decanediol and / or , 12
-Obtained from an aliphatic hydrocarbon diol containing dodecanediol and a polycarboxylic acid, having a number average molecular weight of 1500
The present invention has found a melt adhesive characterized by containing a crystalline polyester polyol having a molecular weight of 15,000 to 15,000.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail. The polyester polyol used in the present invention contains an aliphatic hydrocarbon diol and a polycarboxylic acid as components.
Here, the aliphatic hydrocarbon diols are 1,10-decanediol and 1,12-dodecanediol. Preferably, it is 1,12-dodecanediol. These may be used alone or as a mixture. Further, it can be mixed with an aliphatic hydrocarbon diol having a smaller number of carbon atoms than 1,10-decanediol. The amount of 1,10-decanediol or 1,12-dodecanediol used at this time is not particularly limited, but when a crystalline polyester polyol is obtained, one mole of the aliphatic hydrocarbon diol component is used. %, Preferably 5 mol% or more, more preferably 20 mol% or more. In particular, when it is at least 20 mol%, a highly crystalline polyester polyol can be obtained.

The polycarboxylic acids which are components of the polyester polyol of the present invention are aliphatic dicarboxylic acids and aromatic dicarboxylic acids, and are aliphatic dicarboxylic acids and aromatic dicarboxylic acids having 2 to 12 carbon atoms. Preferably, it is an aliphatic dicarboxylic acid having 2 to 12 carbon atoms. More preferably, they are 2 to 6 aliphatic dicarboxylic acids. Specific examples include oxalic acid, succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, dodecandioic acid, isophthalic acid, and terephthalic acid. Preferred are oxalic acid, succinic acid, adipic acid, suberic acid, sebacic acid, and dodecane diacid. These may be used alone or in combination of two or more.

The polyester polyol obtained in the present invention can be obtained by subjecting the above-mentioned aliphatic hydrocarbon diol component and polyvalent carboxylic acid component to a known dehydration polycondensation. Usually, the equivalent ratio of the hydroxyl group of the aliphatic hydrocarbon diol component to the carboxyl group of the polycarboxylic acid component (hydroxyl group / carboxyl group) is 1.02 to 1.02.
1.5 is preferable, and 1.05 to 1.3 is more preferable.
Specifically, a predetermined amount of the aliphatic hydrocarbon diol and the polyvalent carboxylic acid component in the presence or absence of a catalyst 150 ~
Esterification is performed by dehydration polycondensation in a temperature range of about 250 ° C. for about 3 to 20 hours. As the catalyst at this time, for example, it is also preferable to perform the reaction in the presence of a titanium-based catalyst such as titanium tetrabutoxide or a tin-based catalyst such as dibutyltin oxide, because it promotes dehydration polycondensation.
The catalyst may be charged together with the diol component and the polycarboxylic acid component, or may be added after prepolymerization has been carried out without a catalyst. In the production of polyester polyol, it is desirable to make both terminals almost hydroxyl groups and not to generate carboxylic acid terminals, and for this purpose,
It is particularly advantageous to add the above-mentioned catalyst after performing the pre-polymerization, because it is particularly effective. 1,10-decanediol and / or
Alternatively, the number average molecular weight of a polyester polyol obtained from an aliphatic hydrocarbon diol containing 1,12-dodecanediol and a polyvalent carboxylic acid is from 1500 to 150
00 polyester polyol. Preferably 20
00 to 10000. When it is smaller than this range, heat resistance, chemical resistance and strength at the time of curing are not sufficient, and when it is larger than this range, the viscosity at the time of melting becomes high and it becomes difficult to handle.

The crystallinity in the present invention is only evaluated in the crystallinity measurement by X-ray diffraction (Roland method) of a polyester polyol cooled and solidified at a rate of 10 ° C./min from a molten state, Usually, it should be 40% or more. In particular, when a highly crystallized polyester polyol is intended, those having a crystallinity of 50% or more are preferred. More preferably, the degree of crystallinity is from 50% to 70%.

The polyester polyol used in the present invention comprises 1,10-decanediol and / or 1,12-
It is a crystalline polyester polyol having a number average molecular weight of 1500 to 15000, which is composed of an aliphatic hydrocarbon diol containing dodecanediol and a polyvalent carboxylic acid, and there is no problem in using these alone or as a mixture. Furthermore, it can also be used by mixing with other polyester polyols. In this case, the use amount of the crystalline polyester polyol of the present invention is 0.1% by weight or more, preferably 0.5% by weight or more by weight ratio.

As the polyisocyanate used in the present invention, well-known aromatic, aliphatic and cycloaliphatic diisocyanates and high-functional or high-molecular polyisocyanates are generally used. Specifically, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene Diisocyanate, 1,4-
Phenylene diisocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, cyclohexane-1,4
-Diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-
4,4'-diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, methylcyclohexane diisocyanate and derivatives thereof.

The use range of the polyester polyol and the polyisocyanate is not particularly limited, and is used within a usual range. That is, the molar ratio of the OH group of the polyester polyol to the NCO group of the polyisocyanate is 1: 1.2 to
The ratio is 1: 3.0, preferably 1: 1.5 to 1: 2.5. The reaction conditions are not particularly limited, and the reaction is carried out within a usual range. Specifically, in a temperature range of 50 to 150 ° C., 1
About 5 hours. The reaction can be performed in a solvent.

The viscosity of the molten adhesive obtained in the present invention is not more than 100,000 cps at 120 ° C., preferably 1,000 to 50,000 cps, more preferably 3,000.
~ 40000 cps.

Although the molten adhesive of the present invention can be used as it is, it is possible to add a plasticizer, a thermoplastic polymer, a tackifier, a filler, an antioxidant, etc., which are used in a usual molten adhesive. Can also be used.

The molten adhesive obtained in the present invention is suitable for a continuous bonding step since the bonding time is extremely short. For example, the shoe industry, the lumber processing industry, the paper manufacturing industry, the metal industry, and the resin processing industry can be mentioned.

[0017]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples, but is not limited thereto.

Analysis method (1) Hydroxyl value, acid value and number average molecular weight
It was measured according to SK 1557, and the number average molecular weight was calculated from this hydroxyl value. (2) Crystallinity The crystallinity was determined by heating and melting the produced polyester polyol at a temperature equal to or higher than its melting point, cooling and solidifying the polyester polyol at a rate of 10 ° C./min. It is a value measured and calculated by the line diffraction method (Roland method).

Example 1 230.3 g (1 mol) of dodecane diacid and 1,12
222.6 g (1.1 mol) of dodecanediol was charged into a 500 ml flask equipped with a distillation apparatus, and the atmosphere in the flask was replaced with nitrogen. When the flask was heated to 160 ° C., water began to distill. After stirring at 160 ° C. for 1 hour, stirring at 170 ° C. for 2 hours and 180 ° C. for 2 hours,
Thereafter, the pressure in the flask was reduced to 100 mmHg and the pressure was reduced to 0.1 mmHg.
5 hours, 0.5 hours at 50 mmHg, 10 mmHg
And stirred for 2 hours. After returning to normal pressure once, 9.5 mg of titanium tetrabutoxide was added, and 10 mmH
The mixture was stirred for 8 hours under reduced pressure to complete dehydration polycondensation. The hydroxyl value measured by the method described above was 28, the acid value was 0.32, the molecular weight was 4010, and the crystallinity was 62%.

Examples 2 to 22 and Comparative Examples 1 to 3 Polyester polyols were prepared and analyzed in the same manner as in Example 1 using the diols and polycarboxylic acids shown in Table 1. The obtained results are also shown in Table 1.

[Table 1]

Example 23 The crystalline polyester polyol (D) obtained in Example 1
(DL + DDA) (80.0 g) was placed in a 300-ml separable flask, and the atmosphere was replaced with nitrogen. Subsequently, a 1 / 10N dibutyl phosphate-toluene solution was added in an amount of 1.2 times the amount of titanium tetrabutoxide used in the synthesis of the polyester polyol, and the mixture was added at 130 ° C. for 2 hours.
Stirred for hours. Then, while stirring at 250 rpm, 1
Dehydration treatment at 20 ° C. and 50 mmHg for 1 hour, purging with nitrogen for 10 minutes, and heating to 4,4′-diphenylmethane diisocyanate (MDI) previously heated to 60 ° C.
(Abbreviated as 2.2 times the molar amount to the crystalline polyester polyol) was added at once, and the mixture was further stirred at 120 ° C. for 1.5 hours under a nitrogen atmosphere to synthesize an adhesive.
The obtained adhesive was measured for isocyanate group content, viscosity and set time. These measuring methods are as follows. Physical property measurement method (1) Isocyanate group content The isocyanate group content of the adhesive synthesized by the above method was calculated by the following method. 3 to 6 g of the synthesized adhesive is put in a 300 ml stoppered Erlenmeyer flask, weighed, and completely dissolved in 25 ml of toluene. A toluene solution of dibutylamine (26 g of dibutylamine was added to dry toluene 2)
Dissolve in 00 ml and add 10 ml and shake well. After standing for 15 minutes, 100 ml of 2-propanol and a bromocresol green indicator were added, and N
Titrate with 2/2 hydrochloric acid. Isocyanate content (%) = 21.01 × (BA) × f × 1
00 / S × 1000 A: Amount of N / 2 hydrochloric acid required for titration of sample (ml) B: Amount of N / 2 hydrochloric acid required for titration of blank test (ml) S: Weight (g) of polyester polyol f : Factor of N / 2 hydrochloric acid (2) Viscosity measurement BH type viscometer, rotor No. 7 (Φ3.175 mm, L
= 50 mm) at a rotation speed of 10 rpm and a temperature of 120 ° C. (3) Measurement of set time The set time was measured according to the A method of the Japan Adhesive Industry Association Standard JAI7.
Corrugated cardboard (Kraft Liner B flute) was used as the adherend. The test piece was 50 mm wide and 100 mm long,
Two types of flute directions were prepared: parallel to the width (test piece material C) and perpendicular to the width (test piece material D). Melting temperature 12
The adhesive adjusted to 0 ° C. is applied to the surface of the test piece material C in a string shape in parallel with the flute, and bonded so that the flute crosses on the back surface of the test piece material D, and pressed to test. It was a piece. The bonding conditions are an adhesive application amount of 3 g / m, an open time of 2 seconds, and a pressing load of 2 kg. The application position of the adhesive is 25 mm from the longitudinal end of the test piece material C.
Position. While the pressing time was measured with a stopwatch, the pressing was released at regular intervals, and immediately thereafter, the bonded portion of the bonded test piece was broken in a peeling manner. At this time, the shortest elapsed time of pressing, which shows a material failure rate of 80% or more for an adhesion test piece of 80% or more, was measured as a set time. The measurement of the set time was performed in an environment at room temperature of 20 ° C. Table 2 shows the obtained results.
Are shown together.

Examples 24 to 44, Comparative Examples 4 to 6 Using polyester polyol and MDI shown in Table 2,
An adhesive was synthesized in the same manner as in Example 23, and the measurement of isocyanate group content, viscosity, and set time were measured. The obtained results are also shown in Table 2.

[Table 2]

Examples 45 to 48 Polyester composition as shown in Table 3 and MD
Using I, an adhesive was synthesized in the same manner as in Example 23,
The isocyanate group content measurement, viscosity measurement and set time measurement were performed. The obtained results are also shown in Table 3.

[Table 3]

[0024]

According to the present invention, it has become possible to obtain a molten adhesive which can be produced from readily available raw materials, can be quickly cured and dried, and has a sufficient adhesive strength.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mikito Kashima 8-1 Goi-minamikaigan, Ichihara-shi, Chiba Ube Industries, Ltd. Polymer Research Laboratory Co., Ltd. 1 Ube Industries, Ltd. Polymer Research Laboratory (72) Inventor Joshi Hoshino 8-1 Goi Minami Coast, Ichihara-shi, Chiba Prefecture Ube Industries, Ltd. Polymer Research Laboratory (72) Inventor Riichi Machida Goi-Minami, Ichihara City, Chiba Prefecture 8-1 Ube Kosan Co., Ltd. Polymer Research Laboratory F term (reference) 4J034 DF16 DF20 DF21 HA07 HC03 HC12 HC13 HC22 HC46 HC61 HC64 HC67 HC71 RA08 4J040 ED032 ED042 ED052 EF111 EF291 EF301 JB01 LA01 LA02 LA06 MA02 MA08 MA09 MA10 MA13

Claims (5)

[Claims] 1. A molten adhesive comprising a reaction product of a polyisocyanate and a polyester polyol, comprising:
It is obtained from an aliphatic hydrocarbon diol containing 10-decanediol and / or 1,12-dodecanediol and a polycarboxylic acid, and has a number average molecular weight of 1500 to 150.
A molten adhesive comprising a crystalline polyester polyol which is 00. 2. A polyester polyol cooled and solidified at a rate of 10 ° C./min from a molten state and having a crystallinity of 40 measured by X-ray diffraction (Roland method).
The molten adhesive according to claim 1, which contains a crystalline polyester polyol that is at least 10% by weight. 3. The content of 1,10-decanediol and / or 1,12-dodecanediol is 1% of the total diol.
The molten adhesive according to claim 1, comprising a crystalline polyester polyol obtained from at least mol% of an aliphatic hydrocarbon diol and a polycarboxylic acid. 4. The content of 1,10-decanediol and / or 1,12-dodecanediol is 1% of the total diol.
３０30 mol% of aliphatic hydrocarbon diol and C 2-6
The melt adhesive according to claim 1, further comprising a crystalline polyester polyol obtained from a polycarboxylic acid containing an aliphatic dicarboxylic acid. 5. The molten adhesive according to claim 1, wherein an aliphatic hydrocarbon diol containing 1,12-dodecanediol is used.