JPS5933143B2 - Polyester coating agent - Google Patents

Description

Detailed Description of the Invention The present invention provides a polyester coating which has particularly excellent adhesion to metals, has excellent water resistance and anti-blocking properties, has a suitably hard coating film, and has considerable flexibility. This is related to drugs.

BACKGROUND ART At present, coating agents are generally applied to the inner or outer surfaces of cans of soft drinks, beer, etc., mainly for the purpose of preventing corrosion and improving printability.

As these coating agents, various resins such as epoxy resins, phenol resins, and vinyl chloride-vinyl acetate copolymer resins are used depending on the purpose. In order to satisfy heat resistance and processability, thermosetting resins such as epoxy resins or phenolic resins and vinyl chloride are generally used.
Thermoplastic resins such as vinyl acetate copolymer resins are used in combination. However, all of the above-mentioned resins currently in use have drawbacks such as insufficient flexibility or insufficient moisture permeability, resulting in cracks in the coating layer and easy corrosion. Focusing on these drawbacks, the present inventors have developed a resin that has greater flexibility than conventional thermoplastic resins such as vinyl chloride-vinyl acetate copolymer resin, has significantly superior adhesion to metals, and has sufficient resin hardness. As a result of extensive research in order to provide a coating agent with low moisture permeability, the present invention was achieved. That is, the present invention provides a copolyester having repeating ester units consisting of an acid component and a glycol component, in which (1
) Two or more aromatic dicarboxylic acid components having a terephthalic acid component of 20 to 80 mol% based on the total acid components, or (
The aromatic dicarboxylic acid component of 1 old building or more is 20 to 99 mol% of the total acid component (however, the terephthalic acid component is 10 mol% or more of the total acid component) and the aliphatic dicarboxylic acid component is 80 to 99 mol% The main component is a copolymerized polyester consisting of an aromatic carboxylic acid component and/or an aliphatic carboxylic acid component containing 1 mol% and (lli) 0.1 to 10 mol% of a sulfonate metal salt based on the total acid components. It is a polyester coating agent. Examples of the aromatic dicarboxylic acid component constituting the copolymerized polyester of the present invention include aromatic dicarboxylic acid residues of terephthalic acid, isophthalic acid, and 2,6-naphthalene dicarboxylic acid, and examples of the aliphatic dicarboxylic acid component include adipic acid. , azelaic acid, sebacic acid, dodecanedioic acid, and other aliphatic dicarboxylic acid residues.

Furthermore, aromatic carboxylic acids and/or aliphatic carboxylic acids containing sulfonate metal salts are alkali metal salts of sulfonic acids having one or two ester-forming carboxyl groups, such as sulfoterephthalic acid, 5-
Sulfoisophthalic acid, 4-sulfonaphthalene-2 ・
Examples include alkali metal salts of 7-dicarboxylic acid, 3-sulfobenzoic acid, and ester-forming derivatives thereof, and sodium or potassium salts of 5-sulfo-isophthalic acid are particularly preferred. Examples of the aromatic carboxylic acid component and/or aliphatic carboxylic acid component containing the sulfonate metal salt of the present invention include residues of the above carboxylic acids. The amount of the acid component constituting the copolymerized polyester of the present invention based on the total acid component is as follows. ([) 20 to 80 mol% of terephthalic acid component and 80 to 20 mol% of other aromatic dicarboxylic acid components or (Ii) 20 to 99 mol% of terephthalic acid component and other aromatic dicarboxylic acids (with 10 mol% of terephthalic acid component) above) and an aliphatic dicarboxylic acid component of 80 to 1 mol% and an aromatic carboxylic acid and/or aliphatic dicarboxylic acid component containing a (111) sulfonate metal salt of 0.1 to 1
Hardness of copolyester produced when the amount of aromatic dicarboxylic acid and/or aliphatic dicarboxylic acid component containing 0 mol%, preferably 0.5 to 5 mol%, sulfonate metal salt is less than 0.1 mol%. There is no improvement in adhesion to metal.

Moreover, if it exceeds 10 mol %, the melt viscosity increases significantly, making it difficult to obtain the desired highly copolymerized polyester by melt polymerization. Even if the amount of the carboxylic acid component containing the sulfonate metal salt is 0.1 to 10 mol% of the total acid components, the terephthalic acid component is less than 20 mol% of the two or more aromatic dicarboxylic acid components. If so, the softening point of the copolymerized polyester will be too low, causing blocking development, and furthermore, the hardness will be insufficient.

Moreover, if the terephthalic acid component exceeds 80 mol %, the adhesion to adherends, especially metals, will be significantly reduced, and the adhesive strength will also be extremely low. Furthermore, if the aromatic dicarboxylic acid component is less than 20 mol% of the aromatic dicarboxylic acid component and the aliphatic dicarboxylic acid component, the softening point of the copolymerized polyester will be too low, causing a blocking phenomenon, and the hardness will also be insufficient. . Further, even if the aromatic dicarboxylic acid component is 20 to 99 mol %, if the terephthalic acid component is less than 10 mol %, the hardness of the copolyester will be insufficient and a blocking phenomenon will occur.

In addition, the alkylene glycol components constituting the copolymerized polyester include alkylene glycols such as ethylene glycol, 1,3 propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and neopentyl glycol. is the residue of

These alkylene glycols may be used alone or together with other glycols such as diethylene glycol, triethylene glycol, cyclohexanedimethanol, or the glycol represented by the following general formula (I). A: C2-C5
alkylene group n: an integer of 1 or more m: an integer of 1 or more n+m: 2 to 6 X: a C, to C6 alkylene group, -SO2-, -0-, or absent.

Examples of the glycol represented by general formula (I) include 2,2-bis[4-(2-hydroxyethoxy)phenyl]propane, 2,2-bis[4-(3-hydroxyethoxy)phenyl]propane,
-Hydroxypropoxy)phenyl]propane, bis[
4-(2-hydroxyethoxy)phenyl]sulfone, 4.4'-bis(2-hydroxyethoxy)
Examples include biphenyl.

Regarding the glycol component constituting the copolymerized polyester of the present invention, the amount relative to the total glycol component is preferably as follows.

Alkylene glycol component: 40 to 100 mol% The copolymerized polyester in the present invention has a reduced viscosity of 0.2 d1/
It is preferable that it is y or more. When it is less than 0.2 d1/7, the adhesion to metals and the cohesive force of the copolyester are significantly reduced, which may cause peeling and cracking of the coating agent or adhesive layer.

The above-mentioned copolyester can be obtained by polymerizing terephthalic acid, another aromatic dicarboxylic acid, and optionally an aliphatic dicarboxylic acid or an ester-forming derivative thereof and a glycol through a conventional transesterification method or direct esterification. It will be done.

These copolymerized polyesters may be used in combination with thermosetting resins such as epoxy resins, phenolic resins, melamine resins, and urethane resins in order to further improve hardness and heat resistance.

Furthermore, in producing the copolyester of the present invention, a wide variety of esterification or transesterification catalysts commonly used in the production of polyesters can be used to accelerate the reaction.

Furthermore, it is also possible to appropriately select and use various modifiers, stabilizers, additives, etc. depending on the purpose and various physical properties required. Furthermore, other thermoplastic resins such as polystyrene, ethylene monovinyl acetate copolymer polyamide resin, etc. may be blended to the extent that the inherent properties of the resin are not impaired.

There are no particular restrictions on the form in which the coating agent of the present invention can be used; it may be used in the form of a solution by dissolving it in an appropriate organic solvent, or
Any method such as a hot melt type, a film type, or a powder type can be used, and the method may be selected as appropriate.

In addition, it can be used in a wide range of applications regardless of the material or shape of the adherend, but its performance is particularly well demonstrated when used for coating and bonding metal plates, polyester films, polycarbonate plates, polyacrylic plates, etc. .

The effects of the coating agent based on the copolymerized polyester of the present invention include superior heat resistance, adhesion, flexibility, and moisture resistance compared to conventional vinyl chloride vinyl acetate copolymer coating agents. Moreover, it has the same hardness as conventional coating agents.

The coating agent containing the copolymerized polyester of the present invention as a main component can be used not only as a can coating agent but also as a magnetic tape binder, traffic paint, etc. by taking advantage of its properties.

Hereinafter, the present invention will be specifically explained using Examples.

In addition, in the examples, parts simply mean parts by weight. In addition, various physical properties were measured according to the following methods.

Reduced viscosity of O polymer Using a mixed solution of phenol/tetrachloroethane (6/4), the polymer concentration was 0.17/
The measurement was carried out in 25 ml at 30°C.

Softening point of O polymer Measured according to ASTM E28-513T.

A methyl ethyl ketone/toluene (2/8) solution of the polymer is applied onto an O-adhesive aluminum plate (1.6 m77! thick, degreased, manufactured by Showa Aluminum KK) using an applicator and dried.

Also, resins that are difficult to dissolve in solvents are applied using a hot melt applicator (coating thickness: 50 to 80 μm). Next is NT Carter, 10m7! It was divided into 100 L x 10 mm pieces, zero tape was attached, and a peel test was performed. O hardness was measured using a durometer.

O blocking resistance Measured according to JISK-6842 (50°C).

○; No blocking △: Cohesive blocking ×; Adhesion 〃 ○T-peel adhesive strength A film-like adhesive was sandwiched between two test pieces (thickness 100μ size 7cm x 6?) and the temperature was higher than the melting point of the polymer. 6
After heat sealing for 2 minutes at 51<g/Cd at a temperature of 0℃, 1CT! Cut into L-width pieces and store at 23℃ using Tensilon.
The adhesive strength was measured when T-peel was performed at a tensile speed of 200 mm/min.

Adhesive test piece: Aluminum foil (manufactured by Nippon Foil) O shear adhesion strength 2 test pieces (thickness 1.611 size 1C!!L x 10
Sandwich a film of adhesive (adhesive area: 1crii) between C1rL) and heat seal at 5kg/criil for 2 minutes at a temperature of 60℃ above the melting point of the polymer, then heat seal at 23℃ and 100℃ using Tensilon. The adhesive strength was measured when two test pieces were pulled horizontally to the adhesive surface in opposite directions at a pulling rate of 201Q/min.

Adhesion test piece: Aluminum plate (manufactured by Showa Aluminum KK) Molecular weight: Manufactured by Waters, high performance liquid chromatograph model 150-C
Using ALC/GPC, Syodex A is used as a column.
Using C-802 and AC-804, sample concentration 0.057
The molecular weight distribution was measured under the condition of /10ml.

Example 1 285 parts (1.47 mol) of dimethyl terephthalate 285 parts (1.47 mol) of dimethyl isophthalate 18 parts (0) of 5-sodium sulfodimethyl isophthalate.

06 mol) and 446 parts of 1,4-butanediol (4,95 mol)
mole), 2,2-bis[4-(2hydroxyethoxy)
521 parts (1.65 mol) of phenyl]propane and 0.53 parts (0.0015 mol) of potassium oxalate titanate were put into a reaction vessel, and the transesterification reaction was carried out at 160°C to 220°C under a nitrogen stream. I went.

Next, the temperature was raised from 220°C to 260°C over 30 minutes, and the pressure was gradually reduced to 260°C, the pressure was reduced to 0.1 mmHg over 30 minutes, and finally the temperature was heated for 1 hour under this temperature and reduced pressure condition. A condensation reaction was carried out. The polyester (A) thus obtained was subjected to various tests. Similarly, polyester (
B) to (1) were synthesized. Obtained polyester (A)
~(G) had the same polymer composition as the charging composition.
Table 2 shows the physical properties of these polyesters (A) to (1).

The same applies to the table below.

Example 2 Polyesters (A') and (y) obtained by synthesizing copolyesters (N) and (y) having the same charging composition as the copolyester polyester (A) of Example 1 but different in reduced viscosity and softening point (A) was subjected to various tests.

The results are shown in Table 3. Example 3 291 parts (1.5 mol) of dimethyl terephthalate, 44 parts (0.15 mol) of 5-sodium sulfodimethyl isophthalate, 1.
595 parts (6.6 mol) of 4-butanediol and 0.53 parts (0.0015 mol) of potassium oxalate titanate were charged into a reaction vessel, and heated at 160°C to 220°C under a dinitrogen stream.
The transesterification reaction was carried out at °C.

Next, 310 parts (1.35 mol) of dodecanedioic acid was added, and the temperature was raised from 220°C to 260°C over 30 minutes, then the pressure was gradually reduced at 260°C, and the pressure was reduced to 0.1 mmHg over 30 minutes. , over an additional 60 minutes
The polycondensation reaction was carried out under reduced pressure of 1 ml and 1 liter of Hg. The polyester (H) thus obtained was subjected to various tests. Polyesters (1) to (N) having the compositions shown in Table 4 were similarly synthesized.

The obtained polyesters (H) to (N) had the same polymer composition as the charged composition. These polyesters (H
) to (N) are shown in Table 5. Example 4 In place of 5-sodium dimethyl sulfoisophthalate in the copolymerized polyester (H) of Example 3, 5-potassium dimethyl sulfoisophthalate (abbreviated as DSK) and 2-sodium dimethyl sulfoterephthalate (abbreviated as TSN) were used. ) or methyl 3-sodium-sulfobenzoate (B
Copolymerized polyester (0) to (abbreviated as SN)
Q) was synthesized.

The physical properties of the obtained polyesters (0) to (Q) are shown in Table 6.

Claims (1)

[Claims] 1. In a copolymerized polyester having repeating ester units consisting of an acid component and a glycol component, (i) the terephthalic acid component as the acid component is 20% of the total acid component.
-80 mol% of two or more aromatic dicarboxylic acid components, or (ii) 20-99 mol% of one or more aromatic dicarboxylic acid components based on the total acid components (however, the terephthalic acid component is 10 mol% or more)
and aliphatic dicarboxylic acid component 80-1 mol% and (
iii) an aromatic carboxylic acid component containing 0.1 to 10 mol% of a sulfonate metal salt based on the total acid component;
Or a polyester coating agent whose main component is a copolymerized polyester consisting of an aliphatic carboxylic acid component.