JPS6243479A - Polyester-based adhesive - Google Patents

Abstract

PURPOSE:To provide the titled adhesive having excellent heat-resistance and adhesivity and composed of a copolymerized polyester having a specific intrinsic viscosity and containing aromatic and aliphatic dicarboxylic acid components, an aromatic diol represented by a specific formula and aliphatic and alicyclic glycols at specific ratios. CONSTITUTION:The objective adhesive is composed of a copolymerized polyester having an intrinsic viscosity of >=0.2 [measured in a mixture of phenol and tetrachloroethane (1:1 by weight) at 20 deg.C] and composed of (i) an acid component consisting of (A) 90-50mol% aromatic dicarboxylic acid and (B) 10-50% 2-36C aliphatic dicarboxylic acid and (ii) a glycol component consisting of (C) 70-15mol% compounds selected from the aromatic diols of formula I and II (R1-R4 and R1'-R4' are H, halogen, hydrocarbon group or halogenated hydrocarbon group; X is O, S, SO2, CO, alkylene or alkylidene; the H of alkylene or alkylidene may be substituted with one or more halogen atoms) and (D) 30-85mol% aliphatic glycol and/or alicyclic glycol.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an adhesive comprising a copolyester having excellent heat resistance and adhesiveness.

<Prior art><Problems to be solved by the invention> Thermoplastic copolymerized polyester resin can be used for metals, polyester,
It has excellent adhesion to plastics such as polyvinyl chloride and is electrically insulating.

Adhesive for electrical parts such as 9-can paint and FPC because it has good performance in terms of heat resistance and chemical resistance.

It is widely used in various fields such as adhesives for polyvinyl chloride.

However, due to the thermoplastic nature of thermoplastic copolyester resins that have such performance, heat resistance is limited to around the softening point of the resin, and if the joining area is exposed to temperatures higher than that, the joining will fail. Polyester resin, which has the drawback of being easily destroyed and has excellent heat resistance, is no exception. For this reason, various efforts have been made to improve heat resistance.

Generally, a curing agent is added to a polyester adhesive.
A method has been used to improve heat resistance by creating crosslinks between polyester molecules. for example.

A reaction between a carboxyl group or hydroxyl group in a polyester molecule and a compound having an epoxy group or an isocyanate group has been proposed. However, compositions containing these curing agents have poor stability as adhesives, and the reaction proceeds gradually from the time they are blended.

−・Difficult to use as a liquid; two-liquid type.

That is, the main agent and the curing agent must be prepared separately and mixed immediately before use, which poses the problem of complicated operations. Similarly, since the reaction continues even after it is applied to an adherend, it is not only necessary to perform the bonding work immediately, but also to apply the adhesive to the adherend in advance and heat activate it in a separate process to bond it. Such a method cannot be used either. Furthermore, when hot-melt adhesives are melted at high temperatures and used in applicators, etc., various problems occur such as the reaction progressing in the applicator and solidification. Therefore, there was a desire for a resin suitable for use as an adhesive.

In order to increase the heat resistance of monosulfur or resin alone, it is said that the melting point of crystalline polymers and the glass transition point of non-grade polymers can be increased. However, when using it as an adhesive, various factors other than heat resistance must be considered.

That is, crystalline polymers with high melting points, such as polyethylene terephthalate and polybutylene terephthalate, have almost no solvent to dissolve them.

It cannot be used as a solution type, and it is difficult to use as a hot melt type due to its high melting point.

Furthermore, due to shrinkage of the resin due to crystallization, the adhesion to the adherend is also poor. In addition, there are amorphous polymers with high glass transition points, such as polyarylates, which are effective for molding, but when used as adhesives, they lack stable solvents.
Further, since the cohesive force is too strong, there is a problem that the adhesiveness to the adherend is poor.

Therefore, it has been desired to develop a resin that has excellent heat resistance and excellent adhesion to metals and plastics.

<Means for Solving the Problems> As a result of intensive studies aimed at providing an adhesive with excellent performance as described above, the present inventors developed a copolymerization method in which a specific amount of aromatic glycol was copolymerized. It was discovered that polyester has a high softening point or glass transition point and excellent heat resistance.

This has led to the present invention.

That is, in the present invention, the acid component is an aromatic dicarboxylic acid of 90 to
50 mol% and 1 aliphatic dicarboxylic acid having 2 to 36 carbon atoms
0 to 50 mol%, and the glycol component is represented by the following general formula (1) to III) [where r RI + RZ
+ R3+ R4+ RIZ R2Z R3', R4'
is selected from the group consisting of a hydrogen atom, a halogen atom, a hydrocarbon group, and a halogenated hydrocarbon group, and X is o, ' s,
so□, CO, an alkylene group or an alkylidene group, and the hydrogen atom of the alkylene group or alkylidene group may be substituted with one or more halogen atoms. Consisting of 70 to 15 mol% of two or more types and 30 to 85 mol% of aliphatic glycol and/or alicyclic glycol, and has an intrinsic viscosity [in a mixed solvent of phenol:tetrachloroecune=1:1 (weight ratio), [measured at 20° C.] is at least 0.2.

Examples of the aromatic dicarboxylic acid that is a component of the copolymerized polyester in the present invention include terephthalic acid, isophthalic acid, phthalic acid, and naphthalene dicarboxylic acid, and one or more of these can be used. In particular, terephthalic acid or a mixture of terephthalic acid and isophthalic acid is preferably used. The amount used is 90 to 50 mol% of the acid component, preferably 85 to 55 mol%.
It is mole%. When the aromatic dicarboxylic acid content exceeds 90 mol %, the resulting copolyester is hard, has a high softening point, and is difficult to dissolve in solvents, making it difficult to use as an adhesive. Also.

If it is less than 50 mol%, the softening point will be low, making it impossible to obtain the desired copolyester with high heat resistance.

As an aliphatic dicarboxylic acid having 2 to 36 carbon atoms.

Straight-chain aliphatic dicarboxylic acids and/or those with branches, such as succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, undecanniic acid, dodecanniic acid, brassicic acid, hexadeandioic acid, icosanniic acid, docosanniic acid, etc. In addition to isomers of , dimer acids are also preferably used, and one or more of these can be used. The amount used is 10 to 50 mol% of the acid component.
.

Particularly preferred is 15 to 45 mol%. When the amount of linear aliphatic dicarboxylic acid is less than 10 mol%, the adhesive becomes hard;
The softening point is also high (which makes it difficult to dissolve in ?8 agents. Also,
When it exceeds 50 mol%, the softening point becomes low and the desired heat resistance cannot be obtained. Also.

As the acid component, polyhydric carboxylic acids such as trimellitic acid and pyromellitic acid can also be used in an amount of 10 mol% or less.

The aromatic diol used in the present invention has the general formula (1
) or I[I].

Preferred examples include 9, such as 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'-dihydroxyphenylsulfone, 4,4'-dihydroxydiphenylsulfone, 4
．． 4'-dihydroxydiphenyl ether, 4.4'~
Dihydroxydiphenyl sulfide, 4.4'-dihydroxydiphenylketone, 4゜4'-dihydroxydiphenylmethane, 2.2-bis(4-hydroxy-3,5
-dimethylphenyl)-propane, 1,1-bis(4-
Hydroxyphenyl)-echune, 1,1-bis(4-hydroxyphenyl)-cyclohexane, 4,4'-dihydroxydiphenyl, henzoquinone, etc. are used alone or in a mixture of two or more thereof. Further, although these aromatic diols are rose-substituted diols, some of other isomers may also be used. The most typical aromatic diol is 2,2-bis(4-hydroxyphenyl)-propane (usually referred to as bisphenol A).
, 4,4'-dihydroxyphenylsulfone (commonly referred to as bisphenol S). Further, these halogen-substituted products have a flame retardant effect and are therefore preferable. The amount used is 70 to 15 mol% of the glycol component, especially 60 to 15 mol%.
20 mol% is preferred. The amount of aromatic diol used is 70
If it exceeds mol%, the resulting copolyester becomes hard and has a high softening point.

It becomes difficult to use as an adhesive because it becomes less soluble in solvents. Moreover, if it is less than 15 mol%, the glass transition point will be low, making it difficult to obtain the desired heat resistance.

Examples of aliphatic glycols include ethylene glycol, 1,2-propanediol, 3-propanedalicol, 1,4-butanediol, 1,5-bentanediol, 1,6-hexanediol, neopentyl glycol, Diethylene glycol.

Examples of the alicyclic glycol include triethylene glycol, and examples of the alicyclic glycol include cyclohexane dimetatool, and one or more of these can be used. Especially when the content of the aromatic dicarboxylic acid component in the acid component is large.

It is preferred to increase the proportion of aliphatic glycol in the glycol component. Furthermore, as the glycol component, poly(oxymethylene) glycols such as polyethylene glycol and polytetramethylene glycol, and polyhydric ols such as trimethylolpropane and pentaerythritol can be used within the range that does not impair the properties of the adhesive.

In the mixed solvent of phenol/tetrachloroethane of the copolymerized polyester in the present invention at a ratio of 1:1 (weight ratio), 2
The intrinsic viscosity measured at 0° C. requires at least 0.2. If it is less than 0.2, the molecular weight of the resin is too low, the cohesive force decreases, and problems arise in terms of adhesion to adherends, etc.

The method for producing the copolymerized polyester in the present invention is not particularly limited, and can be carried out in accordance with known ordinary methods. For example, the aromatic dicarboxylic acid component,
Aliphatic dicarboxylic acid component.

It is possible to adopt a method in which the aromatic diol component, aliphatic glycol component, and/or alicyclic glycol component are directly esterified simultaneously or stepwise, or a method is performed in which the aromatic diol component, the aliphatic glycol component, and/or the alicyclic glycol component are directly esterified, or they are subjected to transesterification reaction and then polymerized. In addition, a transesterification reaction is carried out between a high molecular weight or low molecular weight copolyester and an aromatic diol or its acetylated product,
Depending on the case, it is also possible to adopt a method in which polymerization is performed thereafter. Furthermore, known ester-forming derivatives such as alkyl and allyl esters can also be used as the acid component. During these polymerization or transesterification reactions,
Various known catalysts and stabilizers.

Modifiers or additives may also be used.

The copolyester in the present invention can be used alone as an adhesive, but it can also be used as a flame retardant.

Additives such as stabilizers and antiblocking agents, inorganic fillers, and the like can also be included as necessary.

Adhesive properties can be improved by adding a curing agent such as an epoxy compound, isocyanate compound, melamine compound, or ethyleneimine compound having at least two reactive groups to the polyester adhesive made of the copolymerized polyester of the present invention. Heat resistance can be further improved.

The polyester adhesive made of the copolymerized polyester of the present invention can be dissolved in a solvent and used as a solution type adhesive.
In addition, it can be applied in a molten state onto an adherend using a general real melt applicator or roll coater, or in the form of powder, chips, tape, etc.
It is also possible to form the adhesive into various shapes such as a string, film, or wave shape, place it on an adherend with scissors, and then heat it at a temperature higher than the softening point of the adhesive to fuse the adherend.

<Example> The present invention will be explained in more detail below using two examples.

In addition, "part" in 9 examples means "part by weight."

Further, the characteristic values in one example were measured by the following method.

(1) Softening point ('C) Measured by the ring and ball method according to JIS JAI-7.

(2) Glass transition point ('C) In accordance with JIS K-7213, it is shown as the peak temperature of the logarithmic damping rate curve determined by the free torsional vibration method.

(3) Peel adhesive strength (kg/25 fins) Peel adhesive strength at 20°C and 80°C was measured at a peeling rate of 50 mm/min according to JIS K-6854.

Example 1 50 moles of dimethyl terephthalate, 35 moles of isophthalic acid, 15 moles of adipic acid and 91 moles of ethylene glycol, 49 moles of neopentyl glycol, 2.2-bis(4
-Hydroxyphenyl)-propane acetylated product 20
Mol and 0.01 mol % of zinc acetate as a catalyst were placed in a stainless steel reactor, and a transesterification reaction was carried out at 150°C to 250°C under a nitrogen stream. Then antimony dioxide 0
．． 02 mol was added thereto, and polycondensation was carried out at 270° C. for 3 hours under reduced pressure to produce a copolymerized polyester. The composition of this copolyester is that the acid components are 50 mol% of terephthalic acid residues and 135 mol% of isophthalic acid residues.

Adipic acid residue 15 mol% 1 glycol component is modified ethylene glycol 540 mol%, neopentyl glycol 4
0 mol%, 2,2-bis(4-hydroxyphenyl)-
20 mol% propane residue is acceptable.

The intrinsic viscosity measured at 20°C in a phenol/tetrachloroethane l/1 (weight ratio) mixed solvent was 0.58° and the glass transition temperature was 85°C.

Glass transition point, softening point, polyester film (75μ thickness)/aluminum plate (1
The peel adhesion strength and solubility in general-purpose solvents such as toluene/MEK and dioxane were measured at 20° C. and 80° C., and the results are shown in Table 1.

Examples 2-5. Comparative Examples 1 to 4 Copolymerized polyesters having various compositions as shown in Table 1 were produced in the same manner as in Example 1, and the glass transition point, softening point, and polyester film/aluminum temporary bonding layer were measured at 20°C and 80°C. Table 1 shows the peel adhesion strength and solvent solubility at °C.

As shown in Examples 1 to 5 in Table 1, the copolymerized polyester of the present invention not only has a high glass transition point and a high softening point, but also has peel adhesion to a polyester film/aluminum plate measured at 20°C and 80°C. The strength is also high,
An adhesive with excellent heat resistance was obtained. Moreover, the solvent solubility was also good.

However, as shown in the comparative examples, those in which no aromatic diol was copolymerized (Comparative Example 1) and those in which a large amount of aliphatic dicarboxylic acid was copolymerized (Comparative Example 4) had a low glass transition point and softening point. In Comparative Example 2), the glass transition point is too high, the solvent solubility is poor, and the adhesive strength is poor. Furthermore, if an aliphatic dicarboxylic acid is not used (Comparative Example 3), the solvent solubility is poor, the peel strength at 20° C. and 80° C. is poor, and the flexibility of the adhesive is also poor.

Example 6 50 mol of dimethyl terephthalate, 30 mol of dimethyl isophthalate, 20 mol of adipic acid, 30 mol of L4-butanediol, 110 mol of neopentyl glycol, and 0.01 mol of zinc acetate as a catalyst were placed in a stainless steel reactor, and nitrogen was added. The transesterification reaction was carried out at 150 to 250°C under air flow. Next.

Add 0.02 mol of antimony dioxide and add 270 mol of antimony dioxide under reduced pressure.
Polycondensation was carried out at ℃ for 3 hours to produce a copolymerized polyester having an intrinsic viscosity of 0.65.

To this copolymerized polyester, 30 moles of acetylated 2,2-bis(4-hydroxyphenyl)-propane was added, and a transesterification reaction was carried out at 270°C for 1 hour in a nitrogen atmosphere, and then at 270°C under reduced pressure for 3 hours. The reaction proceeded to produce a copolymerized polyester having an intrinsic viscosity of 0.55. The composition of this copolyester is as follows: the acid component is 50 mol% of terephthalic acid residue, 30 mol% of isophthalic acid residue, 20 mol% of adipic acid residue, the glycol component is 15 mol% of 1.4-butanediol residue, Neopentyl glycol residue 5
5 mol%, 2.2-bis(4-hydroxyphenyl)-
Propane residue is 30 mol%, glass transition point is 115°C
, softening point: 185°C1 Good solubility in general-purpose solvents; when polyester film (75μ thick)/aluminum plate (100μ thick) was bonded, peel adhesion strength at 20°C was 2.5 kg/25NM, and at 80°C. An adhesive with peel adhesion strength of 4.0 kg/25 m and excellent adhesion and heat resistance was obtained.

<Effects of the Invention> The polyester adhesive made of the copolymerized polyester of the present invention has a high glass transition point and high softening point.

It has excellent heat resistance and adhesion to plastics and metals such as polyester film and aluminum foil, making it effective for adhesive applications that require heat resistance.

Claims (1)

[Claims] (1) The acid component consists of 90 to 50 mol% of aromatic dicarboxylic acid and 10 to 50 mol% of aliphatic dicarboxylic acid having 2 to 36 carbon atoms, and the glycol component consists of (I) to (III) of the following general formula. There are mathematical formulas, chemical formulas, tables, etc. ▼ (I) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (III) [Here, R_1, R_2, R_3, R_4, R_1′
, R_2', R_3', and R_4' are selected from the group consisting of a hydrogen atom, a halogen atom, a hydrocarbon group, and a halogenated hydrocarbon group, and X is O, S, SO_2, CO, an alkylene group, or an alkylidene group. , the hydrogen atom of the alkylene group or alkylidene group may be substituted with one or more halogen atoms] 70 to 15 mol % of one or more aromatic diols selected from the following and aliphatic glycol and/or 30 to 85 mol% of alicyclic glycol, and has a limiting viscosity [phenol:tetrachloroethane=1:1 (weight ratio)]
A polyester adhesive comprising a copolymerized polyester having a temperature of at least 0.2 (measured at 20°C in a mixed solvent of ).