JP2006233068A - Copolyester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a copolyester good in transparency and free from generation of dullness or precipitate when dissolved in a solvent. <P>SOLUTION: This copolyester is composed of an acid component comprising 2-70 mol% of adipic acid and 30-98 mol% of an aromatic dicarboxylic acid and a glycol component comprising 10-80 mol% of neopentyl glycol. The copolyester contains 100-400 ppm of a solid solution comprising a magnesium compound and an aluminum compound, and has ≥0°C glass transition point and 0.3-1.5 intrinsic viscosity. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a copolyester which has good color tone and transparency and does not cause dullness or precipitation when dissolved in a solvent.

  Polyesters are used in various fields because of their excellent heat resistance, chemical resistance, electrical properties, mechanical properties, etc., and are also widely used as adhesives and paints. When polyester is used as an adhesive or paint, aromatic polyester homopolymers represented by polyethylene terephthalate and polybutylene terephthalate have drawbacks such as high crystallinity and melting point and poor processability. Therefore, by copolymerizing one or more dibasic acid components or glycol components to the aromatic polyester, the crystallinity is lowered, the crystallinity is eliminated, the solubility in the solvent is given, or the melting point is lowered. Heat welding is possible even on adherends with poor heat resistance. In addition, by introducing a bulky substituent to the aromatic polyester, it has hydrolytic resistance, and the processability is improved by adding a component having good flexibility.

  As components that copolymerize with the aromatic polyester, isophthalic acid, adipic acid, sebacic acid and the like are used as the acid component, and diethylene glycol, 1,4-butanediol, neopentyl glycol, 1, and the like as the glycol component. It was common to use 6-hexanediol or the like. Among them, sebacic acid, 1,6-hexanediol, and the like are expensive, and low-cost isophthalic acid, adipic acid, 1,4-butanediol, and neopentyl glycol have been preferably used.

  Various copolymerized polyesters have been used in which adipic acid and neopentyl glycol are copolymerized to lower the crystallinity and glass transition point to improve solubility in solvents, adhesion, and processability. However, in the production of such a copolyester, when an antimony compound that is common as a polycondensation catalyst is used, antimony is reduced during the polycondensation reaction, black fine particles insoluble in the polyester are generated, and the polyester dullness is reduced. Deterioration of the color tone, and when black polyester was used as a solvent-soluble product, caused black precipitates. Moreover, when using this polyester as an adhesive agent or a coating material, in order to form a smooth surface layer, filtration was required, and there existed a problem that a process increased and productivity fell (patent document 1).

  On the other hand, when zinc, tin and titanium compounds are used as the polycondensation catalyst, problems such as dullness and precipitation are solved, but the resulting copolymerized polyester is remarkably colored, so the use for bonding colorless and transparent films to each other, etc. (Patent document 2).

  Further, when a germanium compound is used as a polycondensation catalyst, the problem of dullness and precipitation is solved, but there is a problem that the cost becomes very high (Patent Document 3).

As described above, it is difficult to produce an aromatic polyester obtained by copolymerizing adipic acid and neopentyl glycol having both color tone and transparency.
JP-A-5-239429 JP-A-6-184515 JP 2000-234018 A

  The present invention is intended to solve the various problems associated with polyesters obtained by copolymerization of adipic acid and neopentyl glycol, and to provide a copolymerized polyester having excellent solution transparency when used as a solvent-soluble product.

  As a result of various studies to solve the above problems, the present inventor has found that the above problem can be solved by using a solid solution composed of a magnesium compound and an aluminum compound as a polymerization catalyst, and has reached the present invention.

  That is, according to the present invention, 2-70 mol% of the acid component constituting the polyester is adipic acid, 30-98 mol% is the aromatic dicarboxylic acid, and 10-80 mol% of the glycol component constituting the polyester is neopentyl. A copolymer polyester which is glycol, comprising 100 to 400 ppm of a solid solution composed of a magnesium compound and an aluminum compound, having a glass transition point of 0 ° C. or higher and an intrinsic viscosity of 0.3 to 1.5. The copolyester to be used is the gist.

  According to the present invention, there can be obtained a copolyester having excellent smoothness of an adhesive layer and a coating film without coloring or dullness in an adhesive or paint using a polyester copolymerized with adipic acid and neopentyl glycol. .

Hereinafter, the present invention will be described in detail.
The copolymerized polyester of the present invention is an aromatic polyester obtained by copolymerizing adipic acid and aromatic dicarboxylic acid as an acid component and neopentyl glycol as a glycol component.

  The content of the adipic acid needs to be 2 to 70 mol% with respect to all the acid components constituting the copolymer polyester. Preferably it is 5-50 mol%. Adipic acid is used to lower the crystallinity, melting point and softening point of the copolyester and to impart flexibility. However, if the amount is less than 2 mol%, there is substantially no effect of improving the physical properties, and if it exceeds 70 mol%, the glass transition point of the copolymerized polyester is too low, so that the anti-blocking property. This is not preferable because the tack resistance is deteriorated.

  Further, the copolymer polyester in the present invention needs to contain 30 to 98 mol% of aromatic dicarboxylic acid as an acid component other than adipic acid, and particularly preferably 40 to 90 mol%. . When this content is less than 30 mol%, the post-processability of the coating film when used as a paint is improved, but the hardness and stain resistance of the coating film are reduced and the balance of the coating film performance cannot be maintained. . Moreover, when it exceeds 98 mol%, workability when it is used as an adhesive or a paint is deteriorated, and the solution after dissolving in a solvent may become cloudy or precipitate may be unfavorable. Examples of the aromatic dicarboxylic acid to be copolymerized include terephthalic acid, phthalic acid, isophthalic acid, 5-sodium sulfoisophthalic acid, and 2,6-naphthalenedicarboxylic acid. Among them, terephthalic acid and isophthalic acid are preferable.

  Furthermore, the following acid components may be copolymerized as long as the object of the present invention is not impaired. Examples of the acid component to be copolymerized include aliphatic dicarboxylic acids such as succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid and dodecanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and 1,3-cyclohexanedicarboxylic acid. Examples thereof include alicyclic dicarboxylic acids such as acids, aromatic polycarboxylic acids such as trimellitic acid, trimesic acid, pyromellitic acid and acid anhydrides thereof. Further, hydroxycarboxylic acids such as 4-oxybenzoic acid, 4- (hydroxyethoxy) benzoic acid, and ε-caprolactone and lactone may be copolymerized.

  As a glycol component copolymerized with the copolymerized polyester of the present invention, neopentyl glycol is used, and the content thereof needs to be 10 to 80 mol% with respect to all glycol components constituting the polyester. . Neopentyl glycol is used to improve the weather resistance, wet heat resistance, hydrolysis resistance, and solvent solubility of polyester. However, if this amount is less than 10 mol%, a sufficient improvement effect cannot be obtained. On the other hand, if it exceeds 80 mol%, not only the improvement effect is saturated, but also the polymerizability is low and the productivity is deteriorated.

  Examples of the glycol component copolymerized in addition to neopentyl glycol include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6 -Aliphatic polyhydric alcohols such as hexanediol, 2-butyl-2-ethyl-1,3-propanediol, diethylene glycol, triethylene glycol, trimethylolpropane, pentaerythritol, 1,4-cyclohexanedimethanol, 1,3 -Alicyclic diols such as cyclohexanedimethanol, ethylene oxide or propylene oxide adducts such as bisphenol S and bisphenol A, polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. Lumpur, and the like.

  Since the copolyester of the present invention is produced using a solid solution composed of a magnesium compound and an aluminum compound as a polycondensation catalyst, it contains a solid solution composed of a magnesium compound and an aluminum compound.

  A solid solution composed of a magnesium compound and an aluminum compound is a solid in which they are uniformly melted, and part of these crystal lattices can be replaced by other atoms to change the composition. The molar ratio of aluminum and magnesium (aluminum / magnesium) in the solid solution is preferably 0.1 to 10, and more preferably 0.2 to 5.

  The aluminum compound constituting the solid solution is not particularly limited, but examples thereof include carboxylates such as aluminum hydroxide, aluminum acetate and aluminum benzoate, inorganic acid salts such as aluminum chloride, and aluminum alkoxides such as aluminum methoxide. Side, aluminum chelate compounds such as aluminum acetylacetonate, organoaluminum compounds such as trimethylaluminum, aluminum oxide, and metal aluminum. Of these, hydroxides, carboxylates and inorganic acid salts are preferred, and among these, aluminum hydroxide, aluminum acetate and aluminum chloride are particularly preferred.

  Moreover, as a magnesium compound which comprises a solid solution, magnesium hydroxide, magnesium carbonate, magnesium acetate, magnesium acetylacetonate, carboxylates other than an acetic acid, etc. are mentioned, Especially magnesium hydroxide and magnesium carbonate are preferable.

  In the present invention, the solid solution composed of an aluminum compound and a magnesium compound may contain a metal other than aluminum and magnesium, if necessary.

  The copolymer polyester of the present invention contains 100 to 400 ppm of a solid solution composed of a magnesium compound and an aluminum compound. When the polycondensation reaction is performed so that the solid solution content is less than 100 ppm, the catalytic activity is not sufficient, and thus a copolyester having a sufficient intrinsic viscosity cannot be obtained. On the other hand, when it is added so as to exceed 400 ppm, the color tone of the resulting copolymerized polyester deteriorates, which is not preferable.

  The solid solution composed of the magnesium compound and the aluminum compound may be added at any stage before the polycondensation reaction, but is preferably added immediately before the polycondensation reaction.

  The copolyester of the present invention must have a glass transition point of 0 ° C. or higher. If the glass transition point is less than 0 ° C., it may become liquid at room temperature, which may cause a problem in handling, as well as poor blocking resistance and tacking resistance. Moreover, since the coating film strength and adhesive strength when it is set as a coating material and an adhesive agent become low, it is not preferable.

  The copolyester of the present invention needs to have an intrinsic viscosity of 0.3 to 1.5. If the intrinsic viscosity is less than 0.3, the mechanical strength of the copolyester decreases, and the adhesive strength, coating strength, and bendability when used as an adhesive or paint tend to decrease. When exceeding, when the copolymerized polyester is dissolved in a solvent, the concentration cannot be increased because the solution viscosity is high.

  The copolyester satisfying the above conditions is esterified or esterified at a temperature of 150 to 280 ° C. by using a carboxylic acid component and a glycol component (including their ester-forming derivatives) as raw materials. After performing the exchange reaction, a solid solution composed of a magnesium compound and an aluminum compound is added as a polycondensation catalyst, and the polycondensation reaction is performed at a temperature of 200 to 300 ° C., preferably 230 to 290 ° C. under a reduced pressure of 5 hPa or less. Can be prepared. Furthermore, depending on the purpose and application, it can be prepared by a method in which an acid component and / or a glycol component are added to a polymer obtained by a polycondensation reaction and a depolymerization reaction is performed at a temperature of 220 to 280 ° C.

  In addition, a thermal stabilizer such as phosphoric acid, an antioxidant such as a hindered phenol compound, or the like may be included as long as the effects of the present invention are not impaired.

Next, the present invention will be described with reference to examples. In addition, the physical-property measuring method of copolyester is as follows.
(1) Proportion of acid component The copolyester was measured with a gas chromatograph GC-9A manufactured by Shimadzu Corporation after alkali methanolysis.
(2) Ratio of glycol component The copolymerized polyester was subjected to alkali hydrolysis and then measured with a gas chromatograph GC-9A manufactured by Shimadzu Corporation.
(3) Content of catalytic metal atom The content was measured with a fluorescent X-ray spectrometer 3270 type manufactured by Rigaku Corporation.
(4) Intrinsic viscosity ([η])
The copolymer polyester was determined from the solution viscosity measured at 20 ° C. using an equal mass mixture of phenol and ethane tetrachloride as a solvent.
(5) Glass transition point (Tg)
It measured using the differential scanning calorimeter SSC5200 type | mold by Seiko Denshi Kogyo.
(6) Solution haze (Hz)
The copolymerized polyester was dissolved in a mixed solvent of toluene / methyl ethyl ketone = 8/2 (mass ratio) so that the nonvolatile content would be 30% by mass, and measured using a color difference meter ND-Σ80 type manufactured by Nippon Denshoku Industries Co., Ltd. did. The determination of the solution haze was 2% or less as acceptable.
(7) Color tone (b value)
The copolymerized polyester was dissolved in a mixed solvent of toluene / methyl ethyl ketone = 8/2 (mass ratio) so that the nonvolatile content would be 30% by mass, and measured using a color difference meter ND-Σ80 type manufactured by Nippon Denshoku Industries Co., Ltd. did. The determination of the color tone was performed with a Hunter Lab colorimeter, and the color tone was evaluated using the b value representing yellow-blue. The closer the color tone is to 0, the better, and 10 or less was accepted.
(8) Storage stability The copolyester was dissolved in a mixed solvent of toluene / methyl ethyl ketone = 8/2 (mass ratio) so that the non-volatile content would be 30% by mass. Judgment was made based on the presence or absence of precipitation when allowed to stand for months. The case where there was no precipitation was indicated by ○, and the case where precipitation was generated was indicated by ×.
(9) Smoothness Copolyester was dissolved in a mixed solvent of cyclohexanone / solvesso 150 = 1/1 (mass ratio) to prepare a nonvolatile content of 30% by mass. 100 parts by mass of this polyester solution, 38 parts by mass of titanium oxide (Taipaque CR-50 manufactured by Ishihara Sangyo Co., Ltd.), 8 parts by mass of hexamethoxymethylolamine (Symel 303 manufactured by Sumitomo Chemical Co., Ltd.) Leveling) 2 parts by mass, curing catalyst (catalyst 4040) 0.2 part by mass, cyclohexanone / solvesso 150 = 1/1 (mass ratio) mixed solvent is dispersed and kneaded for 1 hour using a paint shaker. Was made. The obtained paint is applied onto a zinc phosphate-treated steel sheet having a thickness of 0.7 mm so as to have a dry film thickness of 15 to 20 μm, and baked with a hot air dryer for 60 seconds so that the final temperature of the steel sheet is 220 ° C. Went.
The coated surface of the obtained coated steel sheet was visually observed, and “O” indicates that there is no foreign matter, and “X” indicates that there is a foreign matter.
(10) Pencil Hardness The coated surface of the coated steel sheet obtained in (9) above was subjected to a pencil scratch test according to JIS K5400, the hardness without scratches was measured, and a hardness of H or higher was accepted.
(11) Bending property The coated steel plate obtained in (9) above was folded outward by 180 ° and the T number at which no cracks occurred at the bent portion was displayed. The number of T is 0T when bent 180 ° without anything inside the bent part, 1T when the plate of the same thickness as the test plate is folded, and 1T, The case is 2T. The smaller the T number, the better the bendability.

Example 1
The raw material compounds shown in Table 1 were charged into the esterification reaction tank in the amounts shown in Table 1, and an esterification reaction was performed at a pressure of 0.5 MPaG and a temperature of 260 ° C. for 4 hours.
After the obtained esterified product is transferred to a polycondensation reaction tank, it is a solid solution composed of a magnesium compound and an aluminum compound as a polycondensation catalyst (made of HT-P, Sakai Chemical Industry Co., Ltd., aluminum hydroxide, magnesium hydroxide and magnesium carbonate). The molar ratio of aluminum / magnesium is 0.4 ppm with respect to the polyester, and the pressure inside the reaction system is gradually reduced to 0.4 hPa until the final intrinsic viscosity is reached at 270 ° C. A condensation reaction was performed.

Examples 2-7, Comparative Examples 1-8
The same procedure as in Example 1 was performed except that the types and amounts of the raw material compound and the polycondensation catalyst were changed as shown in Table 1. Examples and Comparative Examples Table 1 shows the compositions and characteristic values of the copolymer polyesters obtained.

The copolyesters obtained in Examples 1 to 7 had no problem in the characteristic values such as intrinsic viscosity, color tone and haze.
In Comparative Example 1, since the antimony metal produced during the polycondensation reaction was insoluble in the solvent, not only the solution became cloudy but also a precipitate was produced. In Comparative Examples 2 and 3, the obtained polyester was markedly yellow. In Comparative Example 4, a white precipitate was produced when dissolved in the solvent. Comparative Example 5 was insoluble in the solvent. Since the comparative example 6 had too low Tg, the physical property when it was set as the coating film fell. In Comparative Example 7, since the content of the solid solution composed of the magnesium compound and the aluminum compound was small, the desired viscosity was not increased. In Comparative Example 8, not only the viscosity was too high, but also the color tone of the polyester deteriorated. Further, the obtained copolyester was tried to be made into a paint by the operation described in the above (9). However, when the non-volatile content was 30% by mass, the solution was too viscous to be made into a paint.

Claims (1)

Copolyester in which 2-70 mol% of the acid component constituting the polyester is adipic acid, 30-98 mol% is an aromatic dicarboxylic acid, and 10-80 mol% of the glycol component constituting the polyester is neopentyl glycol A copolyester comprising 100 to 400 ppm of a solid solution comprising a magnesium compound and an aluminum compound, having a glass transition point of 0 ° C. or higher and an intrinsic viscosity of 0.3 to 1.5.