JPH0635533B2 - Polyester composition for adhesive or coating agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a polyester composition for an adhesive or a coating agent, which has excellent heat resistance and adhesion.

<Prior Art><Problems to be Solved by the Invention> Thermoplastic copolymerized polyester resin has excellent adhesiveness to metals, plastics such as polyester and polyvinyl chloride, and electrical insulation, Since it has good heat resistance and chemical resistance, it is widely used in various fields such as adhesives for electric parts such as can paint and FPC, and adhesives for polyvinyl chloride.

However, the thermoplastic copolyester resin having such performance is also limited in heat resistance to the vicinity of the softening point of the resin due to the essence of the thermoplasticity, and when the joining site is exposed to a temperature higher than that, Polyester resins, which have the drawback of being destroyed and have excellent heat resistance, are no exception. Therefore, various efforts have been made to improve heat resistance.

Generally, a polyester adhesive is mixed with a curing agent,
A method has been adopted in which crosslinking is caused between polyester molecules to improve heat resistance. For example, a method of reacting a carboxyl group or a hydroxyl group in a polyester molecule with a compound having an epoxy group or an isocyanate group has been proposed. However, the composition containing these curing agents has poor stability of the adhesive, and the reaction proceeds gradually from the time of the compounding, so it is difficult to use it as one liquid. There is a problem that the agent and the agent must be prepared separately and mixed before use.
Similarly, since the reaction progresses even after being applied to the adherend, urgent joining work is required. A method in which an adhesive is applied to the adherend in advance and heat-activated adhesion is performed in a separate process Cannot be taken. Furthermore, when used as an hot-melt adhesive at a high temperature and used in an applicator, etc., there are various problems such as reaction progressing in the applicator and solidification. Therefore, there has been a demand for a resin having a property suitable for an adhesive application.

Generally, in order to improve the heat resistance of a resin, it is said that the melting point of a crystalline polymer and the glass transition point of an amorphous polymer should be raised. However, when it is used as an adhesive or a coating agent, various other restrictions are introduced. That is, a crystalline polymer having a high melting point, such as polyethylene terephthalate or polybutylene terephthalate, has almost no solvent that dissolves and cannot be used as a solution type, and even a hot melt type has a high melting point, which makes it difficult to use. Furthermore, the adhesion to the adherend is poor due to the shrinkage of the resin due to crystallization. As an amorphous polymer having a high glass transition point, for example, polyarylate and the like exist, but these are also effective for molding, but when used as an adhesive or a coating agent, they still dissolve stably. There is a problem that the adhesiveness to the adherend is poor because the solvent used is scarce and the cohesive force is too strong.

Therefore, it has been desired to develop a polyester composition for adhesives or coatings, which has excellent heat resistance and excellent adhesion to metals and plastics.

<Means for Solving Problems> The inventors of the present invention have made various studies as a result of various studies for the purpose of providing an adhesive or a coating agent having the above-described excellent properties, and as a result, have a fat having a specific composition. It was found that a polyester resin composition comprising a group glycol glycol polyester and an aromatic polyester has a high softening point or glass transition point, is excellent in heat resistance, and has good solubility in a general-purpose solvent, and has arrived at the present invention. is there.

That is, in the present invention, the acid component is 100 aromatic dicarboxylic acid.
-90 mol% and 0-10 mol% of C2-C36 aliphatic dicarboxylic acid, and the glycol component has C2-C2.
80% to 0 mol% of linear aliphatic glycol of 4 and other aliphatic glycol and / or alicyclic glycol 20
To 100 mol% of aliphatic glycol-based polyester (a), and acid components of aromatic dicarboxylic acid of 90 to 50 mol% and C2-C36 aliphatic dicarboxylic acid of 10 to 50
Aliphatic glycol-based polyester comprising 100% by mole of a straight chain aliphatic glycol having 2 to 4 carbon atoms and 0-100% by mole of other aliphatic glycol and / or alicyclic glycol as a glycol component. Aromatic polyester [I] containing 30 to 95% by weight of at least one aliphatic glycol polyester [I] selected from (b), an aromatic dicarboxylic acid as an acid component, and a divalent phenol as a glycol component [ II] A polyester composition for adhesives or coatings, which comprises 70 to 5% by weight.

As the aromatic dicarboxylic acid constituting the aliphatic glycol polyester [I], for example, terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid and the like can be used, and among them, terephthalic acid or a mixture of terephthalic acid and isophthalic acid is preferable. .

Examples of the aliphatic dicarboxylic acid having 2 to 36 carbon atoms include succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassic acid, hexadecanedioic acid, eicosanedioic acid, docosanedioic acid. In addition to linear aliphatic dicarboxylic acids such as acids and / or their isomers having a branch, dimer acids are also preferably used, and one or more of these can be used.

Examples of the linear aliphatic glycol having 2 to 4 carbon atoms include ethylene glycol, 1,3-propanediol and 1,4-butanediol, among which ethylene glycol, 1,
4-butanediol is preferred.

Other aliphatic glycols include, for example, 1,
5-pentanediol, 1,6-hexanediol, or their branched isomers, 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, neopentyl glycol, diethylene glycol, triethylene glycol, etc. Can be given.

Examples of the alicyclic glycol include cyclohexanedimethanol and the like. These aliphatic glycols may be used either individually or in combination of two or more.

The ratio of the acid component and the glycol component constituting the aliphatic glycol-based polyester [I] is 9% of the acid component.
In the case of an aliphatic glycol-based polyester (a) using 0 mol% or more of an aromatic dicarboxylic acid, it has 2 to 4 carbon atoms.
Aliphatic glycols other than straight chain aliphatic glycols and /
Alternatively, it is necessary to copolymerize at least 20 mol% of alicyclic glycol. When the content is 20 mol% or less, the softening point of the aliphatic glycol-based polyester (a) becomes high, and the softening point or glass transition point of the polyester resin composition with the aromatic polyester [II] becomes high, and the polyester resin composition It is hard and difficult to dissolve in a solvent, making it difficult to use as a solvent-type or hot-melt type adhesive or coating agent.

Further, in the case of an aliphatic glycol-based polyester (b) in which an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid having 2 to 36 carbon atoms are used together in the acid component in a molar ratio of 90/10 to 50/50, the glycol component is It can be used without any particular limitation on the number of carbon atoms, branching of carbon chains, or cyclization. The molar ratio of aromatic dicarboxylic acid to aliphatic dicarboxylic acid is 90/10.
˜50 / 50, more preferably 85/15 to 50/50. When the molar ratio exceeds 90/10, the softening point of the aliphatic glycol-based polyester (b) becomes high, so that the polyester resin composition with the aromatic polyester [II] has a high softening point or glass transition point. As a result, the polyester resin composition becomes hard and is difficult to dissolve in a solvent, and it becomes difficult to use it as a solvent-type or hot-melt type adhesive or coating agent. Also, the molar ratio is 50 /
When it is less than 50, aliphatic glycol polyester (b)
Has a low glass transition point, resulting in aromatic polyesters [II]
And the glass transition point of the polyester resin composition becomes low, and the expected heat resistance effect becomes poor.

Aliphatic glycol-based polyester [I] used in the present invention
As the acid component, polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid or oxyacids such as p-oxybenzoic acid, and as the glycol component, polyhydric alcohols such as trimethylolpropane, trimethylolpropane and pentaerythritol. Poly (oxymethylene) glycol such as polyethylene glycol, polytetramethylene glycol, etc. can be appropriately used within a range that does not impair the effects of the present invention.

Such an aliphatic glycol polyester [I] is
The intrinsic viscosity obtained by a melt polycondensation reaction by a conventional method and measured in a mixed solvent of phenol / tetrachloroethane and the like at 20 ° C. is 0.3 or more, and particularly preferably 0.5 or more.

The aromatic polyester [II] used in the present invention comprises an aromatic dicarboxylic acid and a dihydric phenol.

Preferred aromatic dicarboxylic acids include terephthalic acid,
There are isophthalic acid and the like, and in particular, a mixture thereof is preferable in terms of melt processability and overall performance. In the case of such a mixture, the mixing ratio is not limited, but terephthalic acid / isophthalic acid 9/1 to 1/9 (molar ratio) is preferable, and particularly in view of the balance of melt processability and performance. /
3 to 3/7 (molar ratio) is desirable.

Dihydric phenols have the following general formula , Where R ₁ , R ₂ , R ₃ , R ₄ , R ₁ ′, R ₂ ′, R ₃ ′,
R ₄ ′ is selected from the group consisting of hydrogen atom, halogen atom, hydrocarbon group and halogenated hydrocarbon group, and X is O, S, S
It is O ₂ , CO, an alkylene group or an alkylidene group (the hydrogen atom of the alkylene group or the alkylidene group may be substituted with one or more halogen atoms if necessary).

Preferred examples of dihydric phenols used in the present invention include, for example, 2,2-bis (4-hydroxyphenyl)-
Propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) -propane, 2,2-bis (4-hydroxy-
3,5-dichlorophenyl) -propane, 4,4'-dihydroxyphenyl sulfone, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl ketone, 4,4'-dihydroxy Diphenylmethane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) -propane, 1,1-bis (4-hydroxyphenyl) -ethane, 1,1-bis (4
-Hydroxyphenyl) -cyclohexane, 4,4'-dihydroxydiphenyl, benzoquinone and the like. These may be used alone or as a mixture.
Moreover, although these dihydric phenols are para-substituted compounds,
Other isomers may be used as long as the effects of the present invention are not impaired, and these dihydric phenols may be used in combination with ethylene glycol, propylene glycol or the like. The most typical of these dihydric phenols is 2,2-bis (4-hydroxyphenyl) -propane, usually called bisphenol A.

Such an aromatic polyester [II] is produced by various methods such as solution polymerization, melt polymerization and interfacial polymerization, and 1 g measured at 25 ° C. in a mixed solvent of phenol / tetrachloroethane = 6/4 (weight ratio). Logarithmic viscosity at / dl is 0.3
Above, especially 0.5 or more is preferable.

The method for producing the polyester composition for an adhesive or coating agent of the present invention includes, for example, extruding an aliphatic glycol-based polyester [I] and an aromatic polyester [II] using a melt extruder, or using a stirring blade. It can be obtained by a method such as stirring and mixing in a reaction vessel having the same, but when the content of the aromatic polyester [II] in the polyester resin composition exceeds 70% by weight, the effect of improving heat resistance is great, The polyester resin composition produced is hard and has a high softening point, and is also difficult to dissolve in a solvent, which makes it difficult to use as an adhesive or coating agent. Further, when the blending amount of the aromatic polyester [II] is less than 5% by weight, the intended polyester composition for adhesive or coating agent having high heat resistance cannot be obtained.

The melt kneading may be carried out at a temperature not lower than the temperature at which both are softened, but it is generally preferable to carry out kneading in the range of 260 to 320 ° C. for 1 to 30 minutes, particularly 5 to 30 minutes.

Further, when performing melt kneading, it is also effective to add a transesterification reaction accelerating catalyst in the range of 0.1% by weight or less for the purpose of promoting the transesterification reaction and shortening the kneading time.

Such transesterification reaction accelerating catalysts are group I a, group II a, b, group IV a, b, group V b, VI of the Short Periodic Table.
It is selected from oxides, hydroxides, organic acid salts and alkoxides of metals belonging to Group Ia and Group VIII, and among them, particularly preferable metals are sodium, calcium, lithium, zinc, cobalt, manganese, titanium and antimony. ，
Germanium can be mentioned. These catalysts
Although it may be added at the time of melt-kneading, it may be added at the time of polycondensation of the aliphatic glycol-based polyester [I].

Further, an organic phosphite or a polyhydric phenol may be added as a heat resistance stabilizer or an antioxidant to the polyester composition for adhesives or coating agents of the present invention. It is preferable to add such a compound when the transesterification reaction is completed.

The polyester composition for adhesives or coating agents of the present invention may contain various flame retardants, stabilizers, additives such as antiblocking agents, and inorganic fillers, if necessary.

In addition, the polyester composition for adhesives or coating agents of the present invention includes an epoxy compound, an isocyanate compound, a melamine compound having at least two reactive groups,
A curing agent such as an ethyleneimine compound or an oxazoline compound can be added.

The polyester composition for an adhesive or coating agent of the present invention is dissolved in a solvent and can be used as a solution-type adhesive agent or coating agent, and in a molten state, it is applied to an adherend by a general hot melt applicator or roll coater. In addition to using by coating, for example, powder,
After being molded into various shapes such as chips, tapes, strings, films, or waves, it is sandwiched between adherends and then heated at a temperature above the softening point of the adhesive to fuse the adherends. You can also

The polyester composition for adhesives or coatings of the present invention can be used as a molding material for forming chips, injection molding, extrusion molding, film molding, sheet molding and the like. Such a molding material is excellent in mechanical strength, particularly impact strength, and a flexible molded article can be obtained. The polyester resin composition of the present invention includes pigments, glass fibers, other reinforcing materials, carbon black,
Various additives such as alumina, silica gel, clay and the like can be blended as necessary.

<Examples> Hereinafter, the present invention will be described in more detail with reference to Examples.

In addition, "part" in an example means a "weight part."

The characteristic values in the examples were measured by the following methods.

(1) Softening point (° C) According to JIS JAI-7, the softening point was measured by the ring and ball method.

(2) Glass transition point (° C) According to JIS K-7213, it is shown by the peak temperature of the logarithmic decay rate curve by the free torsion vibration method.

(3) Peel adhesion strength (kg / 25 mm) According to JIS K-6854, the peel adhesion strength at room temperature (20 ° C) was measured at a peel speed of 50 mm / min.

Reference Example 1 [Production Example of Aliphatic Glycol-based Polyester (a)] 50 mol of dimethyl terephthalate, 50 mol of dimethyl isophthalate, 90 mol of ethylene glycol, 50 mol of neopentyl glycol, and 0.01 mol of zinc acetate as a catalyst are stainless steel reactors. , And under a nitrogen stream at 150 ℃ to 25
The transesterification reaction was carried out at 0 ° C. Then, 0.02 mol of antimony trioxide was added, and polycondensation was performed under reduced pressure at 270 ° C. for 3 hours to produce polyester (a).

The composition of this polyester (a) is such that the acid component is 50 mol% terephthalic acid residue, 50 mol% isophthalic acid residue, the glycol component is 48 mol% ethylene glycol residue, and 52 mol% neopentyl glycol residue, Phenol /
The intrinsic viscosity measured at 20 ° C. in a mixed solvent of tetrachloroethane and the like was 0.65 and the glass transition point was 75 ° C.

Reference Example 2 [Production Example of Aromatic Polyester [II]] A methylene chloride solution of mixed acid dichloride having a molar ratio of terephthalic acid dichloride and isophthalic acid dichloride of 1: 1 and 2,2-bis (4-hydroxyphenyl)- An aromatic polyester (II) was produced by an interfacial polymerization method using an aqueous alkaline solution of propane (usually called bisphenol A). 6/4 of this phenol / tetrachloroethane
The logarithmic viscosity measured at 25 ° C in a gravimetric solvent mixture at 1 gr / dl is
It was 0.66 and the glass transition point was 203 ° C.

Examples 1 to 4 and Comparative Examples 1 to 3 The polyester (a) of Reference Example 1 and the aromatic polyester (b) of Reference Example 2 were mixed at respective compounding ratios shown in Table 1 to give 280 to 300
Using a twin-screw kneading extruder set to ℃, use sodium acetate
Melt kneading was performed in the presence of 0.1% by weight (relative to the polyester resin composition), and the transesterification reaction of both polyesters was performed to prepare polyester resin compositions with various blending ratios.

The glass transition temperature, softening point, peel adhesion strength of the polyester film / aluminum plate contact layer, and solubility in general-purpose solvents such as toluene / MEK and dioxane of these compositions were measured, and the results shown in Table 1 were obtained.

As shown in Table 1, when the composition ratio of polyester (a) and aromatic polyester (b) is in the range of 90/10 to 30/70, the glass transition temperature and the softening point are high, and polyester film / aluminum The peel adhesion strength evaluated by the board contact layer product was also high, and the one having excellent solvent solubility was obtained. As the blending ratio of aromatic polyester (b) increases, the glass transition temperature and softening point rise, and the heat resistance increases. However, if the compounding ratio exceeds 70% by weight, the solubility in a general-purpose solvent deteriorates, and the peeling adhesive strength of the polyester film / aluminum plate contact layer also deteriorates. Also,
When polyester (a) is used alone, the heat resistance is low, and the peel adhesion strength of the polyester film / aluminum plate contact layer product is slightly inferior.

Example 5 50 mol of dimethyl terephthalate, 35 mol of dimethyl isophthalate, 15 mol of adipic acid, 140 mol of neopentyl glycol and 0.01 mol of zinc acetate as a catalyst were placed in a stainless reactor and transesterified at 150 to 250 ° C. under a nitrogen stream. The reaction was carried out. Then antimony trioxide 0.
02 mol was added, and polycondensation was carried out under reduced pressure at 270 ° C. for 3 hours to produce a polyester (c) which is an example of the aliphatic glycol-based polyester (b).

The composition of this polyester (c) is such that the acid component is 50 mol% terephthalic acid residue, 35 mol% isophthalic acid residue, 15 mol% adipic acid, and the glycol component is 100 mol% neopentyl glycol residue. The intrinsic viscosity measured at 20 ° C. in a mixed solvent of tetrachloroethane and the like was 0.68 and the glass transition temperature was 70 ° C.

Using a twin-screw kneading extruder in which 50 parts of this polyester (c) and 50 parts of the aromatic polyester (b) used in Example 1 were set at 280 to 300 ° C. as in Example 1,
Melt kneading was performed in the presence of 0.1% by weight of sodium acetate, and a polyester resin composition was prepared by transesterification of both polyesters.

This composition has a glass transition temperature of 122 ° C. and a softening point of 200.
Excellent heat resistance above ℃, polyester film /
Peel adhesion strength of aluminum plate contact layer is also 3.8kg / 25mm
The solvent solubility was good.

Comparative Example 4 The glass transition temperature of the polyester (C) alone prepared in Example 5 was 70 ° C., the softening point was 158 ° C., and the peel adhesion strength of the polyester film / aluminum plate contact layer was 2.1 kg / 2.
The heat resistance was low at 5 mm, and the adhesive strength was also low. However, the solvent solubility was good.

<Effects of the Invention> The polyester composition for an adhesive or coating agent of the present invention has excellent glass transition temperature and heat resistance, and also has excellent adhesiveness to plastics and metals typified by polyester films and aluminum foils. It also has good solubility in general-purpose solvents.

Continuation of the front page (56) References JP-A-56-2345 (JP, A) JP-A-53-27873 (JP, A) JP-A-57-160 (JP, A) JP-A-61-14934 (JP , A)

Claims (1)

[Claims] 1. An aromatic dicarboxylic acid having an acid component of 100 to 90.
Mol% and aliphatic dicarboxylic acid having 2 to 36 carbon atoms 0 to 10
Mol%, and the glycol component is 80 to 0 mol% of a linear aliphatic glycol having 2 to 4 carbon atoms, and other aliphatic glycol and / or alicyclic glycol 20 to 100
Aliphatic glycol-based polyester (a) consisting of mol%, and an acid component of aromatic dicarboxylic acid 90 to 50 mol% and aliphatic dicarboxylic acid of carbon number 2 to 36 10 to 50
Aliphatic glycol-based polyester comprising 100% by mole of a straight chain aliphatic glycol having 2 to 4 carbon atoms and 0-100% by mole of other aliphatic glycol and / or alicyclic glycol as a glycol component. Aromatic polyester [II] in which 30 to 95% by weight of at least one aliphatic glycol-based polyester [I] selected from (b), the acid component is aromatic dicarboxylic acid, and the glycol component is dihydric phenol [II] ] 70 to 5% by weight of a polyester composition for adhesives or coating agents.