JPH02196881A - Polyester adhesive for liquid fuel feeding part - Google Patents

Abstract

PURPOSE:To provide a hot-melt adhesive for assembling feeding parts of a fuel such as gasoline and composed mainly of a crystalline polyester having a specific melting point and consisting of an acid component composed mainly of terephthalic acid and a glycol component composed mainly of hexanediol. CONSTITUTION:The objective adhesive is composed mainly of a crystalline polyester having a melting point of 80-150% and a relative viscosity of preferably 1.3-1.6 and consisting of (A) an acid component composed of 90-100mol% of terephthalic acid component and 10-0mol% of dicarboxylic acid component other than terephthalic acid component (e.g. isophthalic acid or succinic acid) and (B) a glycol component composed of 80-100mol% of 1,6-hexanediol component and 20-0mol% of a diol component other than 1,6-hexanediol component (e.g. ethylene glycol or neopentyl glycol).

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a polyester adhesive for use in parts for transporting fuel such as gasoline, and more specifically, a polyester adhesive suitable as a hot melt adhesive for assembling parts for transporting fuel such as gasoline. Regarding.

(Prior Art) In general, polymeric materials are used as adhesives or sealants for the purpose of preventing leaks in assembling parts and devices used in fuel delivery systems such as fuel filters, fuel pumps, and fuel pipes. There is. As a basic performance requirement for such polymer materials.

(1) Does not dissolve or swell in fuels such as gasoline.

Impurities such as monomers, oligomers, or decomposition products contained in polymeric materials cannot be eluted, and they do not become brittle even when in contact with fuel for a long period of time.

C) Adhesion or sealing operations can be performed easily and quickly.

Conventionally, polyester adhesives for assembling fuel liquid delivery parts for gasoline, etc. have been made with terephthalic acid as the main acid component (60 to 90 mol% of dicarboxylic acid), ethylene glycol,
A polyester adhesive whose main glycol component is at least one alkylene glycol selected from propanediol and butanediol has been proposed (
(See Japanese Patent Publication No. 62-41551).

(Problems to be Solved by the Invention) In recent years, with the aim of reducing the cost of fuel delivery parts and equipment, there has been an increasing demand for faster production lines and post-processability after adhesion or sealing. Plus, more.

■Further shorten the pot life after adhesion.

■Exhibiting high flexibility (flexibility) etc. are increasingly being demanded.

However, the above-mentioned adhesives have not been able to fully meet such demands.

The present invention aims to solve such problems, and the purpose is to use a polyester resin for fuel liquid delivery parts that can further shorten the pot life after adhesion and provide high flexibility. Our goal is to provide adhesives.

(Means for Solving the Problems) The present inventors have arrived at the present invention as a result of intensive research to solve the above problems.

That is, 1 the present invention contains 90 to 100 mol% of the terephthalic acid component and 10 to 0% of the carboxylic acid component other than the terephthalic acid component.
mol% as acid component, 1,6-hexanediol component 8
0 to 100 mol%, 20 to 0 mol% of diol components other than the 1,6-hexanediol component as a glycol component, and a polyester adhesive for fuel liquid delivery parts whose main component is a crystalline polyester with a melting point of 80 to 150°C. This is the summary.

The present invention will be explained in detail below.

First, the polyester constituting the polyester adhesive of the present invention has a terephthalic acid component of 90 to 100 mol% as an acid component, and a 1,6-hexanediol component of 80 to 100 mol% as a glycol component.

In such a polyester, if the carboxylic acid component other than the terephthalic acid component exceeds 10 mol% of the total acid component, or/and the diol component other than the 1,6-hexanediol component exceeds 20 mol% of the total glycol component,
Not only does the melting point of the polyester decrease, but also the crystallinity tends to decrease and the fuel resistance of the adhesive tends to decrease.

As mentioned above, the polyester constituting the adhesive of the present invention is a crystalline polyester whose main raw materials are terephthalic acid or its derivatives and 1°6-hexanediol or its derivatives.

If it is necessary to lower the melt viscosity or melting point depending on the type of base material, application site, application conditions, adhesion conditions, etc. of the fuel liquid delivery parts, it may be necessary to lower the melt viscosity or melting point by adding 10% by mole or less of the total acid component and 20% of the total glycol component. The copolymerization component described below is used in an amount of mol % or less.

Next, the polyester constituting the polyester adhesive of the present invention has a melting point of 80 to 150°C. When the melting point of polyester is less than 80°C.

This is not preferable because it lacks the heat resistance as an adhesive. On the other hand, if the melting point of polyester exceeds 150° C., it is not preferable because when handling it as a hot melt adhesive, a temperature so high that the effects of hydrolysis, thermal decomposition, etc. cannot be ignored is required.

The relative viscosity of the above polyester is not particularly limited, but considering adhesive strength, workability, etc., it is practically 1.3 to 1.6.
The degree is appropriate.

When the polyester adhesive of the present invention is used as a hot-melt adhesive, the melt viscosity is -1, considering the specifications of coating equipment used for boat fishing, usually at a temperature of 200°C or less.
000-500.000 centipoise, preferably 5,
000 to 100,000 centipoise is used.

The polyester constituting the polyester adhesive of the present invention is prepared by heating terephthalic acid and 1,6-hexanediol to 200 to 260°C to perform an esterification reaction,
Removal of the theoretical amount of water followed by n-butyl titanate n-
Add a polycondensation reaction catalyst such as propyl titanate, antimony trioxide, germanium dioxide, etc. and
It can be prepared by carrying out a polycondensation reaction at 0° C. until a desired average molecular weight (usually controlled by relative viscosity as described above) is reached.

Along with the above terephthalic acid, in an amount of 10 mol% or less, isophthalic acid, phthalic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, 1.10-decanedicarboxylic acid, 1.12-dodecanedicarboxylic acid, 5L-20 (manufactured by Okamura Seyu Co., Ltd., long-chain dicarboxylic acid), dicarboxylic acids such as 1.4-cyclohexanedicarboxylic acid, 1.3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, and oxidized acids such as ε-cabrolactone p-oxybenzoic acid. Acid components can be used.

Also, along with the above 1,6-hexanediol.

Ethylene glycol, 1,2-propanediol, 1,3-propanediol in amounts up to 20 mol%.

1.3-butanediol, 1.4-butanediol1.
5-bentanediol, 1,8-octanediol, 2
-Methyl-1,8-octanediol, l,9nonanediol, LIO-decanediol, 1.12 dodecanediol, st, -20-OH (manufactured by Okamura Seishyu Co., Ltd., long chain aliphatic diol), neopentyl glycol, 1,4-cyclohexane dimetatool, diethylene glycol, triethylene glycol, polyethylene glycol, polytetramethylene glycol, ethylene oxide adducts to bisphenol, and the like can be used.

In the polyester adhesive of the present invention, inorganic fillers such as colloidal silica, talc, kaolin, calcium carbonate, barium sulfate, clay, and titanium dioxide are added to the above-mentioned polyester, if necessary.

Rosin derivatives, terpene resins, waxes, petroleum hydrocarbons, polyolefins such as polyethylene and polypropylene, and the like can be used as long as they do not interfere with the crystallinity, coating workability, and adhesiveness of the polyester.

The polyester adhesive of the present invention can be used not only as an adhesive but also as a sealant.

The polyester adhesive of the present invention can be applied to inorganic materials such as metal and glass, natural organic materials such as paper, wood, and leather, as well as polyvinyl chloride resin, acrylic-styrene resin, acrylic-butadiene-styrene resin, and polycarbonate. It can be effectively used for adhesion of base materials or sealing between base materials for fibers and molding materials made of synthetic resins such as resin, polyethylene terephthalate resin, and polybutylene terephthalate resin.

In the present invention, the melting point, relative viscosity and melt viscosity of polyester are measured by the following method.

(1) Melting point ('C) Measured at a heating rate of 20° C./min using a PerkinElmer Model DSC-II differential scanning calorimeter.

(2) Relative viscosity Dissolve at 0.5 g/100 ml (D concentration) using a mixed solvent of equal weight of phenol/tetrachloroethane and set at 20°C.

(3) Melt viscosity (centipoise) at 200°C using a Brookfield B-type viscometer.
Measure with.

(Function) In the polyester adhesive of the present invention, the polyester that is the main component does not contain a copolymer component or has a relatively small amount of copolymer component, so it exhibits high crystallinity and can be used after bonding or sealing. Not only does it have a short pot life until it can be used, but it also has extremely high fuel resistance.

Moreover, by using 1,6-hexanediol as the main glycol component, it exhibits high flexibility despite having high crystallinity and has excellent post-processability.

Although the polyester constituting the adhesive of the present invention exhibits extremely good fuel resistance due to its high crystallinity, it has a high molecular weight (indicated by relative viscosity) to a level that exhibits sufficient adhesive strength. Despite exhibiting a melt viscosity in a range that is easy to apply and high fuel resistance, it has excellent flexibility, so it is difficult to bond parts with complex shapes, deformation of parts after bonding, and even It also shows high suitability for post-processing such as bending.

(Example) Next, two embodiments of the present invention will be specifically explained using examples.

In addition, in the examples, gasoline resistance and flexibility were evaluated as follows.

(1) Prepare gasoline-resistant polyester into dumbbells with a width of 12.5 mm, a P7 length of 3 mm, and a length of 115 mm, and use them as Intesco® dumbbells. [Using a tensile testing machine, the strength (tensile breaking strength: kg/c*i) and elongation (tensile breaking strength: kg/c*i) and elongation (tensile breaking strength The retention rate (%) of strength and elongation was determined.

(2) Flexibility Evaluation was made based on the elongation of the dumbbell.

Examples 1-5. Comparative Examples 1 to 4 Terephthalic acid (abbreviated as TPA), isophthalic acid (abbreviated as IPA), and adipic acid (ADA) were used as acid components.
1. of the total acid component as the glycol component.
Using 1.6-hexanediol (abbreviated as HD), 1.4-butanediol (abbreviated as BD) and 5L-20-OH (manufactured by Okamura Seishyu Co., Ltd., long chain aliphatic diol) in an amount of 4 times the mole. , in a stainless steel reaction vessel.

After carrying out the esterification reaction at 150 to 240°C and distilling off a nearly stoichiometric amount of water, 6×10-' moles of tetra n-butyl titanate were added as a catalyst per 1 mole of the total acid components, and the mixture was heated at 250°C to 0. Nine polycondensation reactions were carried out under a reduced pressure of 5 ■Hg to prepare polyesters having the composition and properties shown in Table 1.

Subsequently, dumbbells were prepared using each polyester, and the strength and elongation of the dumbbells were measured before and after soaking in gasoline, and the results shown in Table 2 were obtained.

Furthermore, each polyester was attached to a steel plate and a fuel filter paper using a hot melt adhesive handgun.
C. and an adhesion test was carried out with the results shown in Table 3. All had good coatability.

The polyesters of Examples 1 to 5 constituting the hot melt adhesive of the present invention had melting points as shown in Table 1. In addition, it showed a sharp endothermic peak in the melting point measurement by DSC.

It had high crystallinity. Due to its high crystallinity, even by prolonged soaking in gasoline.

As shown in Table 2, there was no decrease in 1 strength elongation, and as shown in Table 3, it had a short pot life.

On the other hand, as shown in Table 1, no melting point was observed in the polyesters of Comparative Examples 1 to 3. In addition, these polyesters were polyesters of low crystallinity that did not have a melting point peak or only showed a broad endothermic peak when measured by DSC. Furthermore, as shown in Table 2, long-term immersion in gasoline caused a large decrease in strength and elongation. Comparative example 1.3
It is possible to copolymerize a large amount of aliphatic dicarboxylic acid such as adipic acid to improve elongation or flexibility, as shown in the polyester shown in Figure 2, but at the same time crystallinity is impaired, resulting in poor gasoline resistance. It can be seen that the is decreasing.

Furthermore, although the polybutylene terephthalate shown in Comparative Example 4 exhibits high gasoline resistance like the polyester of the example, it cannot be coated at a typical hot melt adhesive coating temperature of 200° C. or lower. It has been found difficult to use as a hot melt adhesive.

Table (1) The ratio of acid component and glycol component is mol% Comparative Example 1
A melting point of ~3 is not observed (x mark).

Table (Effects of the Invention) The polyester adhesive of the present invention has good fuel resistance and coating workability, and satisfies the basic performance requirements as an adhesive for fuel delivery parts. Moreover, the pot life after adhesion can be shortened, and furthermore, high flexibility can be provided. Therefore, the polyester adhesive of the present invention can be suitably used as a hot melt adhesive for assembling fuel delivery parts.

Patent applicant Uni-tei Riki Co., Ltd. Shokusha No. 9 filter paper steel plate thickness 1 medium 2.5 false length l0C11
A test piece was used. Before “zaiha” & upper materials,
Indicates that the material has been destroyed.

Claims (1)

[Claims] (1) The acid components are 90 to 100 mol% of a terephthalic acid component, 10 to 0 mol% of a carboxylic acid component other than the terephthalic acid component, 80 to 100 mol% of a 1,6-hexanediol component, and a 1,6-hexanediol component. Melting point 80-15 when glycol component accounts for 20-0 mol% of diol components other than
A polyester adhesive for fuel delivery parts whose main component is crystalline polyester at 0°C.