JPH0195165A - Polyester coating agent - Google Patents

Abstract

PURPOSE:To provide the title coating agent having a high glass transition point, a high softening point and excellent heat resistance, blocking resistance, adhesion, etc., by constituting it from a copolymer polyester having a specified acid component composition and a specified glycol component composition. CONSTITUTION:A copolymer polyester consisting of an acid component (A) comprising at least 80mol% aromatic dicarboxylic acid (A) containing 20-95mol% terephthalic acid and a glycol component (B) containing 30-90mol% aliphatic glycol having a 1 C or higher side chain (e.g., 1,2- propanediol) and 10-50mol% diol of the formula (wherein n and m are each 1-3, and R is H for methyl) is mixed as a principal component with necessary additives such as a solvent and a flame retardant. The obtained coating agent can show excellent adhesiveness to, e.g., a steel sheet.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a polyester coating agent, and more specifically to a polyester coating agent that has excellent heat resistance and adhesion and is suitable for coating 1W4 boards, plastics, films, etc. This invention relates to a polyester coating agent made of polymerized polyester.

(Prior art) Thermoplastic copolymerized polyester resin has excellent adhesion to plastics such as polyester and polyvinyl chloride, and metals, as well as good heat resistance and chemical resistance. It is dissolved in organic solvents such as methyl ethyl ketone and is widely used in various applications such as coating agents for two cans of paint and surface coating agents for plastics. However, polyester resins that are currently dissolved in organic solvents and used as coating agents generally have low heat resistance, so when used as paints or coating agents, the drying process after coating or the winding process after drying is difficult. If the temperature rises slightly during the process, etc., it has the disadvantage of causing blocking.

For this reason, when polyester resin is used as a coating agent for boat fishing, a method is adopted in which a curing agent is blended to cause crosslinking between the molecules of the polyester resin to improve heat resistance.

For example, it has been proposed to use, as a curing agent, a compound having an epoxy group, methylol group, or isocyanate group that is reactive with the carboxyl group or hydroxyl group of polyester resin.

(Problem to be Solved by the Invention) However, when these curing agents are used, the heat resistance after the curing process is good, but the heat resistance is not improved before the curing process, so the drying process and winding process Problems such as occurrence of blocking still occur in the process. Further, depending on the intended use, it may not be possible to incorporate a curing agent.

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

The present invention aims to solve the problems of the prior art, and its purpose is to use a polyester-based material that is heat resistant, difficult to cause blocking, and has excellent adhesion. The objective is to provide a coating agent.

(Means for Solving the Problems) The present inventors aimed to provide a coating agent having excellent performance as described above.

As a result of intensive research, it was discovered that polyester copolymerized with a specific glycol has excellent heat resistance and adhesion, and the present invention was achieved.

That is, in the present invention, (a) the acid component is an aromatic dicarboxylic acid of 80 mol % or more, of which terephthalic acid accounts for 20 to 95 mol %, and (b) the glycol component has a carbon number of 1. The gist of the present invention is a polyester coating agent comprising a copolymerized polyester containing 30 to 90 mol% of an aliphatic glycol having the above side chain and 10 to 50 mol% of a diol represented by the following general formula [I].

However, n and m are integers of 1 to 3, and R represents a hydrogen atom or a methyl group.

The present invention will be explained in detail below.

As the acid component of the copolymerized polyester in the present invention,
At least 80 mol% is aromatic dicarboxylic acid, preferably 90-100 mol%. When the proportion of aromatic dicarboxylic acid is less than 80 mol%.

The glass transition point of copolyester is also lowered.

Heat resistance decreases and blocking resistance tends to deteriorate.

Next, the proportion of terephthalic acid in the aromatic dicarboxylic acid is 20 to 95 mol%, preferably 30 to 90 mol%.
It is mole%. When the proportion of terephthalic acid exceeds 95 mol%, toluene in the copolymerized polyester.

The solubility in organic solvents such as methyl ethyl ketone decreases, and the copolyester tends to become hard and brittle. On the other hand, when it is less than 20 mol%, the glass transition point becomes low, heat resistance decreases, and blocking resistance tends to decrease.

Examples of aromatic dicarboxylic acids include isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, and the like in addition to terephthalic acid. Among these aromatic dicarboxylic acids, isophthalic acid is preferably used as a mixture with terephthalic acid.

Further, examples of dicarboxylic acids other than aromatic dicarboxylic acids include succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, 8 undecanoic acid, dodecanoic acid, brassic acid, hexadecaniic acid, icosaniic acid, docosaniic acid, etc. Saturated aliphatic dicarboxylic acids and/or their branched isomers and alicyclic dicarboxylic acids are preferred.

Moreover, these dicarboxylic acids may be used alone or may contain two or more kinds. Dicarboxylic acids other than these aromatic dicarboxylic acids, that is, non-aromatic dicarboxylic acids, are 20
It is used in a range of 0 to 0 mol%.

Furthermore, the acid component is trimellitic acid.

It may contain polyhydric carboxylic acids such as pyromellitic acid, oxybenzoic acid, etc. in an amount of 10 mol% or less.

Next, as the glycol component of the copolymerized polyester in the present invention, 30 to 90 mol% thereof is an aliphatic glycol having a side chain having one or more carbon atoms. The proportion of aliphatic glycol having such a side chain is preferably 40 to 80 mol%. If the proportion of the aliphatic glycol having the above side chain is less than 30 mol%, toluene in the copolyester,
The solubility in organic solvents such as methyl ethyl ketone tends to decrease, and if the concentration exceeds 90 mol%, the above general formula [I
] The proportion of diol represented by is less than 10 mol%,
Heat resistance decreases.

Examples of such glycols are 1,2-propanediol, neopentyl glycol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,2-bentanediol.

2.3-pentanediol, 1,4-bentanediol, 1,4-hexanediol, 2.5-hexanediol, 3-methyl-1,5-bentanediol, 1,2
-dodecanediol, 1,2-octadecanediol, etc., and these may be used alone or in combination of two or more.

Next, 10 to 50 mol % of the glycol component is an ethylene oxide or propylene oxide adduct of the diol represented by the above general formula [I], that is, 4,4'-dihydroxy-diphenylsulfone. The preferred range of such diols is 15 to 40 mol%. If the diol content is less than 10 mol%, heat resistance may decrease or blocking may occur when used as a coating agent.

On the other hand, if it exceeds 50 mol%, the solubility in organic solvents such as toluene and methyl ethyl ketone decreases.

The resin itself becomes hard and brittle, and its adhesion to adherends tends to deteriorate. In addition, in the above formula [1], n,
m is an integer from 1 to 3, and n and m may be the same,
May be different. Moreover, these diols represented by the above general formula [I] may be used alone or may contain two or more kinds.

Further, as long as the properties of the polyester coating agent of the present invention are maintained, glycol components other than the aliphatic glycol having a side chain and the diol represented by the above-mentioned formula CI) may be included as a copolymer component. The proportion of such glycol is preferably about 0 to 45 mol%, although it depends on the proportions of the two types of glycols mentioned above. These glycols include straight chain aliphatic glycols such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 5-bentanediol, 1,6-hexanediol, diethylene glycol, In addition to ethylene glycol, examples include alicyclic glycols such as cyclohexane dimetatool. These glycols may be used alone or in combination of two or more. Furthermore, as a glycol component, a polyhydric ol such as trimethylolpropane may be included in an amount of 10 mol% or less.

The blending ratio of the glycol component in the copolymerized polyester of the present invention is 40 to 60 mol% of the aliphatic glycol having a side chain, 15 to 40 mol% of the diol represented by formula CI), based on the total glycol component. It is particularly preferable that the amount of glycols other than these two types of glycols is 0 to 45 mol%.

The method for producing the copolyester constituting the present invention is not particularly limited, and any known ordinary method can be employed. For example, an alkyl ester of an aromatic dicarboxylic acid, an alkyl ester of an aliphatic dicarboxylic acid if necessary, a diol represented by the above-mentioned formula (r),
It is possible to adopt a method in which an aliphatic diol having a side chain and, if necessary, other aliphatic diols and/or alicyclic glycols are transesterified simultaneously or stepwise and then monopolymerized. Further, a high molecular weight or low molecular weight copolymerized polyester and a diol represented by the above general formula [I] are transesterified.

Depending on the case, a method of carrying out subsequent polymerization may also be adopted. During these polymerization or transesterification reactions, any known catalysts, stabilizers, modifiers, additives, etc. may be used.

The copolyester of the present invention can be dissolved alone in an organic solvent and used as a coating agent as it is, but it may contain additives such as various flame retardants, stabilizers, anti-blocking agents, inorganic fillers, etc. as necessary. You can also do it.

The polyester coating agent of the present invention has excellent heat resistance and good blocking resistance, so a curing agent is not particularly required.

Depending on the application, a small amount of a curing agent such as an epoxy compound, an isocyanate compound, or a melamine compound having at least two reactivities may be blended.

Surface properties such as adhesiveness, heat resistance, water resistance, and surface hardness can be further improved.

The polyester coating agent made of the copolymerized polyester of the present invention can be preferably used as a solution-type coating agent by dissolving it in a solvent. For example, coat one can of paint, coat the surface of plastic D-F+ film, and coat the surface of paper.

Used as a binder, etc. It can also be pulverized and used as a powder coating. Furthermore, it can be melted using a conventional hot melt applicator or roll coater.
It can also be used as a hot-melt coating agent by coating a film or the like.

(Example) The present invention will be explained in more detail below with reference to Examples.

Note that "parts" in the following examples mean "parts by weight."

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

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

(2) Glass transition point ("C) It is shown as the peak temperature of the logarithmic damping rate curve determined by the free torsional vibration method according to JIS-7213.

(3) Adhesion In accordance with JIS-5400, the adhesion to the steel plate was evaluated after treatment at 20° C. and 80° C. for 3 hours by forced peeling with an adhesive tape after the base grain test.

The rating is 1 as stated in JIS-5400.
It is as follows.

10 points: No peeling at all.

8 points: The area of the missing part is less than 5% of the total square area 6 points: The area of the missing part is 5% or more and less than 15% of the total square area 4 points: The area of the missing part is 15% or more and 35% of the total square area
Less than 2 points: The area of the missing part is 35% or more of the total square area or 65%
Less than 0 points: Peeling area is 65% or more of the total square area (4)
Blocking resistance The blocking property at a temperature of 60°C was evaluated according to JIS-K-6833.

Blocking was judged based on the first-order standard.

○Can be easily peeled off without blocking).

△: No evidence of damage was observed on both surfaces.

Adhesive forces are working in some places.

×: Evidence of damage is observed on both surfaces.

(5) Solvent Solubility A 171 (weight ratio) mixed solvent solution of toluene/methyl ethyl ketone was prepared and the solubility was evaluated after one month. ○ indicates complete dissolution, and × indicates that there is an insoluble portion.

(6) Intrinsic viscosity 1/1 of phenol/tetrachloroethane (weight ratio)
Measurement was performed at 20°C in a mixed solvent.

In addition, the abbreviations in the tables for acid components and glycol components indicate the following acids and glycols, respectively.

TPA is terephthalic acid and IPA is isophthalic acid.

ADA is adipic acid, SEA is sebacic acid, EG is ethylene glycol, NPC is neopentyl glycol, B
D is 1,4-butanediol, BSE is 4,4'-dihydroxy-diphenylsulfone ethylene oxide 1
molar adduct.

Example 1 50 moles of dimethyl terephthalate, 50 moles of dimethyl isophthalate, 57 moles of ethylene glycol, 74 moles of neopentyl glycol, 1 mole of ethylene oxide adduct of 4,4'-dihydroxy-diphenyl sulfone (bisphenol S) (hereinafter referred to as BSE) ) and 0.02 mole of antimony trioxide as a catalyst were placed in a stainless steel reactor, methanol was distilled off at 150 to 200°C under a nitrogen atmosphere, and a transesterification reaction was carried out. Next, 0.02 mol of antimony trioxide was added and polycondensation was performed at 270° C. for 4 hours under reduced pressure to produce a copolymerized polyester.

The composition of this copolymerized polyester is that the acid component is 51 mol% of terephthalic acid residue and 49 mol% of isophthalic acid residue, and the glycol component is 29 mol% of ethylene glycol residue and 40 mol% of neopentyl glycol residue.

Ethylene oxide adduct residue 31 of bisphenol S
It was mol%.

Moreover, the intrinsic viscosity is 0.58. Glass transition point is 99°C.

The softening point was 185°C. This copolymerized polyester is 1/1 (ffi ratio) of toluene/methyl ethyl ketone.
Not only could it be dissolved in a mixed solvent to form a solution with a concentration of 30% (by weight), but the viscosity of the solution did not change and was stable even when this solution was stored for 3 months.

Table 1 shows the glass transition point, softening point, adhesion to steel plates, blocking resistance, and solubility in general-purpose solvents such as toluene and methyl ethyl ketone for this copolyester.

Examples 2-4. Comparative Examples 1 to 3 Copolymerized polyesters having various compositions as shown in Table 1 were produced in the same manner as in Example 1. Glass transition point and softening point of these copolyesters.

Table 1 shows the adhesion to steel plates, blocking resistance, and solvent solubility.

Table 1 As shown in Table 1, the copolymerized polyesters of the present invention (Examples 1 to 4) have a high glass transition point and a high softening point. 3
Adhesion to the time-treated steel plate was also good.

It also has anti-blocking properties.

It also had excellent solvent solubility. However, when the ethylene oxide adduct of bisphenol S is not copolymerized and has good solvent solubility as in Comparative Example 1,
Adhesion and blocking resistance after treatment at 80°C were poor. On the contrary, when the softening point and glass transition point were high and the 2 adhesion and blocking resistance were good, as in Comparative Example 3, the solvent solubility was poor. Further, when 60 mol% of BSE is copolymerized as in Comparative Example 2, the degree of monopolymerization is difficult to increase, and the softening point and glass transition point are high, but it is hard.

It can be seen that it becomes brittle, has poor adhesion, and also has poor solvent solubility.

Example 5 50 mol of dimethyl terephthalate, 40 mol of dimethyl sophthalate, 10 mol of adipic acid, 30 mol of 4-butanediol, 110 mol of neopentyl glycol, and 0.02 mol of antimony trioxide as a catalyst were mixed in a stainless steel reactor. The transesterification reaction was carried out at 150 to 250°C under a nitrogen atmosphere. Then antimony trioxide 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 having an intrinsic viscosity of 0.65.

30 mol of ethylene oxide adduct of bisphenol S was added to this copolymerized polyester, and 2
The transesterification reaction was carried out at 70°C for 1 hour, and then the reaction was continued at 270°C for 3 hours under reduced pressure to produce a copolymerized polyester having an intrinsic viscosity of 0.53.

The composition of this copolymerized polyester is that the acid component is 52 mol% of terephthalic acid residue, 30 mol% of isophthalic acid residue, 18 mol% of adipic acid residue, the glycol component is 14 mol% of 1.4-butanediol residue, Neopentyl glycol residues were 57 mol%, and bisphenol S ethylene oxide adduct residues were 29 mol%. Further, the glass transition point was 93°C and the softening point was 177°C. This copolymerized polyester can not only be dissolved in a 1/1 (weight ratio) mixed solvent of toluene/methyl ethyl ketone to obtain a solution with a concentration of 30% by weight, but also this solution can be stored for 3 months. The viscosity of the solution did not change and was stable.

Table 2 shows the glass transition point, softening point, adhesion to polyethylene terephthalate film, blocking resistance, and solubility in general-purpose solvents such as toluene and methyl ethyl ketone for this copolyester.

Examples 6-7. Comparative Examples 4 to 5 Copolymerized polyesters having various compositions as shown in Table 2 were produced in the same manner as in Example 5. Glass transition point and softening point of these copolyesters.

Adhesion to polyethylene terephthalate film,
Blocking resistance and solvent solubility are shown in Table 2.

As shown in Table 2, the copolyesters of the present invention (Examples 5 to 7) in which the aromatic dicarboxylic acid accounts for 80 mol% or more of the acid components of the copolyesters have a glass transition point and a softening point. Adhesion to polyethylene terephthalate film at 20°C and 8
Adhesion to polyethylene terephthalate film after treatment at 0° C. for 3 hours was also good. Also,
It also had excellent blocking resistance and solvent solubility. However, as shown in the comparative example, those containing less than 80 mol % of aromatic dicarboxylic acid had poor adhesion and blocking resistance to polyethylene terephthalate film at high temperatures.

Example 8 6 parts of Coronate L (isocyanate curing agent manufactured by Nippon Polyurethane Co., Ltd.) was added to 100 parts of the copolymerized polyester produced in Example 1 in a 1/1 (weight ratio) mixed solvent of toluene/methyl ethyl ketone. Dissolved and prepared coating solution. The concentration of this coating solution is 20
% by weight. This coating solution was coated on a 75 μm polyethylene terephthalate film for 10 min after drying.
Apply it to a thickness of 1.0 μm, and leave it at room temperature for 1 day after drying.

A cured coating film was created.

The polyethylene terephthalate film with this cured coating has excellent surface heat resistance, can withstand instantaneous contact with a heating element at a temperature of 300°C or more, and has also been tested in accordance with JIS-5400. It had a rating of 10, indicating excellent adhesion.

(Effects of the Invention) The polyester coating agent made of the specific copolymerized polyester of the present invention has a high glass transition point and softening point, excellent heat resistance, good blocking resistance, and also has good adhesion. Excellent.

It exhibits excellent adhesion to polyester film sticks and metals, and is suitable as a coating agent that requires heat resistance.

Claims (1)

[Claims] (1) (a) The acid component is 80 mol% or more of aromatic dicarboxylic acid, of which terephthalic acid accounts for 20 to 95 mol%, and (b) the glycol component has 1 or more carbon atoms. 30 to 90 mol% of aliphatic glycol having a chain, the following general formula [I]
A polyester coating agent comprising a copolyester containing 10 to 50 mol% of a diol represented by: ▲There are mathematical formulas, chemical formulas, tables, etc.▼...[I] However, n and m are integers from 1 to 3, and R represents a hydrogen atom or a methyl group.