JPS5911383A - Hot-melt adhesive - Google Patents

Abstract

PURPOSE:To provide a hot-melt adhesive consisting mainly of a polyester resin made from dicarboxylic acid compoent, low molecular weight glycol component and polytetramethylene glycol and exhibiting excellent and durable adhesion to a soft vinyl chloride resin. CONSTITUTION:A polyester resin with a melting point of 80-160 deg.C is prepared from a dicarboxylic acid component consisting of 90-50mol% terephthalic acid and 10-50mol% dicarboxylic acid other than terephthalic acid (e.g. succinic acid), a low molecular weight glycol component consisting of 30-75mol% 1,4- butanediol and 70-25mol% diethylene glycol and polytetramethylene glycol with a molecular weight of 500-6,000 which is used in an amount of 0.1- 5mol% of the total dicarboxylic acids. The hot-melt adhesive with excellent softeness and flexibility contains the thermoplastic copolyester resin as an effective ingredient.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hot one-melt adhesive containing a thermoplastic copolymerized polyester resin as an active ingredient and having excellent softness and flexibility. More specifically, a copolymer polyvarnish having excellent adhesion and durable adhesion to vinyl chloride resins, particularly soft vinyl chloride resins.

Regarding chill resin.

In recent years, hot melt adhesives have been recognized for their non-polluting, high-speed adhesion, and ease of bonding operation, and have been used for a variety of purposes. Polyester resins represented by polyethylene terephthalate and polybutylene terephthalate are widely used in various fields such as fibers, films, and molding materials due to their excellent mechanical strength, thermal stability, water resistance, and chemical resistance. .

These polyesters are highly crystalline, rigid, and have a high melting point.
Cannot be used as hot melt adhesive, but
By introducing other components into the dicarboxylic acid and diol components, which are the constituent components, it is possible to obtain resins having various features, and many reports and proposals have been made. Such so-called copolymerized polyester resins are generally known to have excellent adhesion to plastics such as polyester, polycarbonate, polyvinyl chloride resin, and metal foils such as aluminum and copper.

However, the so-called durable adhesion, which has high initial adhesion to these adherends and maintains its performance over a long period of time, is influenced by the resin properties of the copolyester. In particular, when a soft vinyl chloride resin containing a large amount of a low molecular weight plasticizer (low molecular weight esters such as dioctyl phthalate) is bonded with a hot melt adhesive, a problem arises after one contact. This decrease in adhesive strength is noticeable in copolyester resins having crystallinity, and is slow in non-quality resins. However, non-grade polyester resins lack heat resistance and are prone to blocking, so they cannot be used as hot melt adhesives with excellent flexibility and heat resistance.

In consideration of these various problems, the present inventors have developed a hot melt adhesive that has excellent flexibility and flexibility, as well as excellent initial adhesion and durable adhesion to soft vinyl chloride resin, and heat resistance. As a result of intensive studies to achieve this goal, we have arrived at the present invention. That is, the present invention provides a polyester resin comprising a dicarboxylic acid component, a low molecular weight glycol component, and a polytetramethylene glycol component, in which the dicarboxylic acid component is comprised of 90 to 50 mol% of terephthalic acid and 10 to 50 mol% of a dicarboxylic acid other than terephthalic acid. The low molecular weight glycol component is 1,4-butanediol 30-'
75 mol% and diethylene glycol 70-25 mol%, and furthermore 0.1-5 mol% based on the total dicarboxylic acids.
It is a hot melt adhesive mainly composed of a polyester resin having a melting point of 80 to 160'C and consisting of polytetramethylene glycol having a molecular weight of 500 to 60 oO in mole %.

The dicarboxylic acid component used in the present invention consists of 90 to 50 mol% of terephthalic acid and 10 to 50 mol% of a dicarboxylic acid other than terephthalic acid. However, if the 1-terephthalic acid content exceeds 90 mol%, the flexibility of the polyester resin will decrease. It becomes defective. On the other hand, if the amount of terephthalic acid is less than 50 mol%, the crystallinity of the polyester resin will become poor and the heat resistance will decrease, which is not preferable.

Examples of dicarboxylic acid components other than terephthalic acid include succinic acid, adipic acid, azelaic acid, sebacic acid, orthophthalic acid, isophthalic acid, and 5-sodium sulfoisophthalic acid. These copolymerizable dicarboxylic acid components can be used alone or in combination, but it is necessary to consider the melting point, crystallinity, and flexibility of the polyester resin.

As dicarboxylic acids other than terephthalic acid, it is preferable to mainly use adipic acid and isophthalic acid.

The preferable range of terephthalic acid and dicarboxylic acid other than terephthalic acid is 90 to 50 mol% of terephthalic acid and 20 to 45 mol% of dicarboxylic acid other than terephthalic acid.

On the other hand, the low molecular weight glycol components are 1.4-butanediol 30-75 mol% and diethylene glycol 70-75 mol%.
It consists of 25 mol%. If the content of 1,4-butanediol is less than 30 mol%, the crystallinity of the polyester resin 5- will be poor and the heat resistance will be insufficient. On the contrary, 1.4
- If the content of butanediol exceeds 75 mol%, the resin will lack flexibility and its durable adhesive properties will also be poor. Small amounts of ethylene gelcol, 1,6-hexanediol, and 1,4-hexane dimetatool may be contained as low molecular weight glycols.

Molecular weight copolymerized to the polyester resin of the present invention: 500
~6000 polytetramethylene glycol is preferably 0.1 to 5 mol% based on the total acid components, preferably 0.5 to 2.0%.
It is mole%. Together with diethylene glycol, polytetramethylene glycol has a great effect on imparting flexibility to resins, and is a major factor in imparting adhesive durability. If the amount of polytetramethylene glycol is less than 0.1 mol, the contact layer durability will be poor, and if it exceeds 10 mol %, the heat resistance will be poor.

In the present invention, it is necessary to select a composition from the above copolymer composition so that the melting point of the polyester resin is 80 to 160°C. If the melting point is less than 80°C, heat resistance is insufficient and the resin tends to develop stickiness, causing problems during storage and use. On the other hand, if the melting point exceeds 160° C., the temperature used for bonding becomes too high, which may cause shrinkage or damage to the adherend, which is undesirable. A desirable melting point is 90 to 140°C.

The method for producing the hot melt adhesive of the present invention is not particularly limited, and can be carried out according to a conventional method. For example, terephthalic acid and other dicarboxylic acids or ester-forming derivatives thereof are directly esterified or transesterified with the above-mentioned glycol simultaneously or stepwise, and then a polycondensation reaction is carried out under vacuum. Any of the various conventional catalysts, stabilizers and additives may be used.

The hot melt adhesive in the present invention is formed into various shapes such as pellets, powder, film, and non-woven fabric, and is applied to the adherend using a method 1 melting applicator in which it is inserted into the adherend and bonded by heating. Various methods can be employed, such as a method in which the adherend is coated in the form of a film or tube using an extruder and then glued together.

The hot melt adhesive of the present invention may optionally contain a stabilizer,
Filler 1 Pigment and its geothermal plastic resin may be mixed as appropriate.

The hot melt adhesive of the present invention has moderate crystallinity\
It has outstanding flexibility. In particular, when used for adhering soft vinyl chloride resin, it exhibits excellent heat resistance and durable adhesion, with little decrease in adhesive strength over time. The reason for this is not clear, but it is thought that it has good compatibility with vinyl chloride resin and also with plasticizer.
It is presumed that this is because the low-molecular plasticizer contained in the soft vinyl chloride resin dissolves into the hot melt adhesive through the adhesive interface.

The hot melt adhesive of the present invention can also be used as a flexibility improver for vinyl chloride resin.

When used in combination with a small amount of low-molecular plasticizer or mixed alone with vinyl chloride resin, various problems arise due to surface migration of the plasticizer, which is a disadvantage of conventional low-molecular plasticizers (for example, pollution, protection, hygiene, etc.). It has the characteristics of a polymeric plasticizer that reduces the physical properties (e.g.) and has durability. Further, by mixing the hot melt adhesive of the present invention into a vinyl chloride resin, it is possible to improve the adhesiveness of the vinyl chloride resin, particularly to impart adhesiveness to polyester. The hot melt adhesive of the present invention has excellent adhesion to fibers, plastics, metal foil, sheepskin, rubber, etc., and can also be used as adhesives for these where flexibility is required.

Hereinafter, the present invention will be explained in more detail with reference to Examples. In the examples, parts indicate total parts. The reduced viscosity of the copolymerized polyester was measured at 30°C in a mixed solvent of phenol/tetrachloroethane-60/40 (weight ratio). The melting point was measured using a fully automatic melting point measuring device (Msttler, Model I).
FF-1). T-peel adhesion strength was measured using Tensilin at a stretching speed of 200-. Flexibility is 50μ
Judging from the texture of the film.

973 parts of dimethyl terephthalate, 566 parts of 1,4-butanediol, 546 parts of diethylene glycol/42 parts of polytetramethylene glycol (molecular weight 1050), 15 parts of potassium titanate oxalate, 1 part of antimony trioxide
After charging 9 parts of triphenylphosphite and carrying out the transesterification reaction at 160 to 220 °C for 3 hours, 1 part of triphenylphosphite was added.
．． Add 3 parts and adipine t1!1409 parts 220~25
The esterification reaction was carried out at 0°C for 1.5 hours. Then 26
The pressure was slowly reduced to 0.degree. C., and the polycondensation reaction was carried out for 3.5 hours under a reduced pressure of 0.1 to 0.31111H9.

As a result of compositional analysis, the composition of the copolymerized polyester (A) was 64 mol% of terephthalic acid, 36 mol% of adipic acid, and 1.4-
Butanediol 60 mol%, diethylene glycol 40
It was mol%.

A 50μ film prepared by dissolving this copolymerized polyester powder in polyproform was sandwiched between soft vinyl chloride resin sheets (95μ) at 130°C.

a. 5 and 9/d for 15 seconds. (The bonding temperature was 20°C higher than the melting point.) Next, a 25u x 150+W test piece was cut from this adhesive piece and kept at room temperature (230'C) and hot (a).

°C and 80 °C), and T after being left at 80 °C for one month.
-The peel adhesion strength was determined to be 14゜5kg/2 for each
5m5+.

2.5119/25 m So, 8119/25 +m
, 11.3~/25 Dragon.

Examples 2-3, Comparative Examples 1-6 The reduced viscosity and flexibility are shown in Table-1.

In addition, Table 2 shows the results of an adhesion test conducted in the same manner as in Example 1.
It was shown to.

Claims (1)

[Claims] In the z161J ester resin consisting of a dicarboxylic acid component, a low molecular weight glycol component, and a polytetramethylene glycol component, the dicarboxylic acid component is terephthalic acid 9
0 to 50 mol% and dicarbonate other than terephthalate #
Consists of 1 to 50 mol% of diluted alcohol, and the low molecular weight glycol component is 30 to 1,4-butanediol.
From 75 mol% and diethylene glycol 70 to 25 mol%, and further from 0.1 to 5 mol% to all dicarbonyl
A hot-melt adhesive based on a polyester resin having a melting point of 80 to 160°C and consisting of polytetramethylene glycol having a mol% of molecules Ji[t5oo to 6000.