JPH06255059A - Laminated polyester film - Google Patents

Abstract

PURPOSE:To obtain excellent flexibility, transparency by laminating a polyester containing aromatic, aliphatic dicarboxylate residue, as acid ingredient, 1,4- butanediol residue as glycol ingredient, and a polyester containing aromatic dicarboxyliate residue, 1,4-butanediol residue as main ingredients. CONSTITUTION:A polyester A contains a hard segment containing 50-90mol% of aromatic dicarboxylate residue as acid ingredient as main ingredient, a soft segment containing 5-50mol% of aliphatic dicarboxylate residue as main ingredient, and 1,4-butanediol residue as glycol ingredient. A polyester B to be laminated at least on one side surface of the polyester A contains aromatic dicarboxylate residue and 1,4-butanediol residue as main ingredients. In order to set wet tension of at least one side surface of the laminated polyester film to 40 dynes/cm or more, the polyester B having high wet tension is used or corona discharge treatment is performed.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a laminated polyester film having flexibility. More specifically, the present invention relates to a laminated polyester film having transparency, elasticity recovery, heat resistance, film forming property and flexibility excellent in processability.

[0002]

Polyester, especially polyethylene terephthalate, polybutylene terephthalate or poly-
1,4-cyclohexane dimethylene terephthalate and polyesters based on these have excellent physical properties,
It has chemical properties and is widely used as fibers, films and molded products.

However, all of them are limited in flexibility and elasticity recovery at room temperature, so that there is a limit to expansion of applications. In order to improve such a defect, a method of copolymerizing a polyester with a soft segment has been considered. For example, JP-B-57-48577 discloses a copolymer of polybutylene terephthalate with a long-chain polyether such as polytetramethylene glycol, and JP-B-42-8709 discloses polyethylene terephthalate with a dimerized fatty acid. Copolymerized long-chain aliphatic dicarboxylic acid, and Japanese Patent Publication No. 5
JP-A-4-15913 discloses a copolymer of polybutylene terephthalate with a dimerized fatty acid.

[0004]

However, copolymerization of polybutylene terephthalate with a long-chain polyether is inferior in processability, heat resistance and transparency, and polyethylene terephthalate has a long-chain aliphatic dicarboxylic acid. The polymerized product has a slow crystallization rate and is difficult to be formed into a fiber, a film, a sheet, and other molded articles. Further, a copolymer of polybutylene terephthalate and a dimerized fatty acid has a high crystallinity and a high melt viscosity, and when formed into a film or the like, a film having a uniform thickness cannot be obtained and is partially whitened. There was a defect that transparency was lost.

The present invention is intended to solve the above-mentioned conventional drawbacks and provides a laminated polyester film having flexibility excellent in transparency, elastic recovery, heat resistance, film-forming property and processability. With the goal.

The above-mentioned object of the present invention is, in the repeating unit constituting the polyester, 50 to 95 mol% of an aromatic dicarboxylic acid residue and 5 to 50 mol% of an aliphatic dicarboxylic acid residue as an acid component and 1 as a glycol component. Characterized in that a polyester B containing 4,4-butanediol residues as a main constituent is laminated on at least one surface of a polyester B containing aromatic dicarboxylic acid residues and a 1,4-butanediol residue as a main constituent. It can be achieved by the laminated polyester film.

In the present invention, the polyester A is a hard segment containing an aromatic dicarboxylic acid residue as a main constituent as an acid component, a soft segment containing an aliphatic dicarboxylic acid residue as a main constituent, and a glycol segment mainly containing 1 , 4-butanediol residue.

In the present invention, the aromatic dicarboxylic acid residue constituting the hard segment is formed from an aromatic dicarboxylic acid and its ester-forming derivative. Specific examples include the following.

[0009]

[Chemical 1]

(X in the formula is -0-, -SO-, -SO _2- , -C (C
_{H 3) 2 -, -CO-,} n is 0 or 1. Further, the hydrogen atom bonded to the aromatic ring may be replaced with a halogen atom. )

In the present invention, examples of the acid component constituting the aromatic dicarboxylic acid residue include the following.

[0012]

[Chemical 2]

(Wherein R ^{1 to} R ⁶ are hydrogen atoms or alkyl groups, X is -0-, -SO-, -SO _2- , -C (CH ₃ ) ₂ -,-
CO-, n is 0 or 1. Further, the hydrogen atom bonded to the aromatic ring may be replaced with a halogen atom. )

Specific examples include terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenyletherdicarboxylic acid, benzophenonedicarboxylic acid, and ester-forming derivatives thereof. Of these, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, and ester-forming derivatives thereof are preferable. In addition, these aromatic dicarboxylic acid components are 1
One kind or two or more kinds may be used in combination.

In the present invention, the amount of the aromatic dicarboxylic acid residue is required to be 50 to 95 mol% of the acid component, more preferably 55 to 93 mol%, and further preferably 60 to 90 mol%. %. When the amount of the aromatic dicarboxylic acid residue is less than 50 mol%, the heat resistance of the polyester is lowered, and the mechanical properties of a molded product obtained from the polyester are lowered. On the other hand, when the amount of the aromatic dicarboxylic acid residue exceeds 95 mol%, the flexibility of the molded product decreases.

In the present invention, the aliphatic dicarboxylic acid residue constituting the soft segment is formed from an aliphatic dicarboxylic acid having 6 to 50 carbon atoms or its ester-forming derivative. When the carbon number is less than 6, the melting point of the polyester is lowered and the heat resistance is lowered. On the other hand, when the carbon number exceeds 50, the reactivity decreases.

The aliphatic dicarboxylic acid used in the polyester A of the present invention mainly has a linear or branched structure and partially has an alicyclic functional group or an aromatic ring functional group. I don't mind. Further, the molecule may have a functional group containing a halogen atom or a sulfur atom.

Specific examples of the aliphatic dicarboxylic acid used in the polyester A of the present invention include adipic acid,
Pimelic acid, suberic acid, azelaic acid, sebacic acid,
Undecadioic acid, dodecadioic acid, brassic acid, tetradecadioic acid, pentadecadioic acid, hexadecadioic acid, heptadecadionic acid, octadecadioic acid, nonadecadionic acid, eicosandioic acid, heneicosandioic acid, docosandionic acid , Straight-chain aliphatic dicarboxylic acids such as tricosandionate, tetracosandionate, pentacosandionate, hexacosandionate, heptacosandionate, octacosandionate, nonacosandionate, triacontandionate and the like The ester-forming derivative, the dimer acid obtained by dimerizing an unsaturated fatty acid having 10 to 25 carbon atoms, a hydrogenated product thereof, an ester-forming derivative thereof, and the like. In particular, dodecanedioic acid, dimer acid and hydrogenated products thereof are reactive,
It is preferable in terms of cost.

In the present invention, the amount of the aliphatic dicarboxylic acid residue is required to be 5 to 50 mol% of the acid component, more preferably 7 to 45 mol%, and further preferably 10 to
It is 40 mol%. The amount of aliphatic dicarboxylic acid residues is 50
When the content is more than mol%, the heat resistance and reactivity of the polyester are deteriorated, and the mechanical properties of a molded product such as a film obtained therefrom are deteriorated. On the other hand, when the amount of the aliphatic dicarboxylic acid residue is less than 5 mol%, the flexibility of the molded product such as the film obtained from the polyester decreases.

Further, the melt viscosity of polyester A is 250
When the temperature is 500 poise or more and less than 2500 poise at a temperature of 0 ° C., the thickness of the laminated film becomes uniform, which is preferable.

In the present invention, the glycol component is mainly a 1,4-butanediol residue. Since the polyester of the present invention has high crystallinity by using 1,4-butanediol as a main component in glycol,
The film obtained from the polyester has a little change over time, and a good film can be obtained. However, even if one or more kinds of glycols selected from aliphatic, alicyclic and aromatic diols having 10 or less carbon atoms are added within a range where the change with time is reduced, that is, a range of less than 10 mol% of the glycol component. I don't care.

Further, the glass transition temperature (Tg) of polyester A is preferably 20 ° C. or lower, more preferably 10 ° C. or lower, and further preferably 0 ° C. or lower in order to obtain good flexibility.

The polyester B having an aromatic dicarboxylic acid residue and a 1,4-butanediol residue as main constituents laminated on at least one surface of the polyester A is not particularly limited, but the acid component residue and the glycol component residue are not particularly limited. It is desirable that 80 mol% or more, preferably 90 mol% or more of the groups are the aromatic dicarboxylic acid residue and the 1,4-butanediol residue. The dicarboxylic acid component residue is composed of the above dicarboxylic acid component residue, but the aromatic dicarboxylic acid residue is 90 mol% in terms of dimensional stability and processability.
The above is desirable. Polybutylene terephthalate, isophthalic acid copolymerized polybutylene terephthalate, dodecanedioic acid copolymerized polybutylene terephthalate and the like can be preferably used as the polyester B in terms of dimensional stability, processability and cost. 2 as a copolymerization component
More than one acid or glycol component may be used.

Glass transition temperature (Tg) of polyester B
Is preferably 10 to 60 in terms of dimensional stability and workability.
℃, more preferably 10 to 40 ℃, more preferably 1
It is 0 to 38 ° C.

In the present invention, the intrinsic viscosity of the polyester is 0.3 in order to obtain good moldability and mechanical properties.
It is preferably −2.0 dl / g, more preferably 0.35 to 1.8 dl / g, and further preferably 0.4 to 1.5 dl / g.

The method for producing the polyester in the present invention is not particularly limited, but for example, an esterification reaction is carried out from an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid or their lower alkyl esters and 1.4-butanediol. Alternatively, the most general method is a method of producing by a first stage reaction for producing a low polymer by a transesterification reaction and a second stage reaction for polycondensing this low polymer. More specifically explaining the above method, dimethyl terephthalate, dimethyl dimerate, 1,
4-butanediol was mixed with a stirrer, nitrogen gas inlet pipe,
It is charged in a polymerization reactor equipped with a vacuum distillation apparatus, and heated at a low temperature of 150 to 250 ° C. while flowing nitrogen to stir to carry out a transesterification reaction. After that, gradually reduce the pressure,
Polyester is obtained by carrying out a polycondensation reaction at a temperature of 200 to 300 ° C. under a reduced pressure of 0.001 to Torr. During this reaction, transesterification catalysts such as titanium, lead, zinc, calcium, magnesium, manganese compounds, polycondensation catalysts such as antimony, germanium, titanium compounds, antioxidants, stabilizers such as phosphorus compounds, etc. are used. I can do it. Further, it is possible to increase the molecular weight by solid-phase polymerization within the scope of the present invention.

As the constitution of the laminated polyester film of the present invention, A / B, B / A / B, B / A / B ′ (polyester B ≠ polyester B ′), or a multilayer may be laminated. In particular, it is preferable to have a layer B or another layer on both sides of A because handling is easy and film blocking is less likely to occur. The ratio of the total thickness of the layer composed of polyester A to the total thickness of the layer composed of polyester B is 1: 1 to 1
It is preferable that the ratio is 00: 1, preferably 25: 1 to 100: 1 (total A layer: total B layer) because the flexibility, processability, and dimensional stability are good.

The film is stretched or unstretched, but is not particularly limited, but it is preferably substantially unstretched from the viewpoint of flexibility. Young's modulus of the film is 1 to 50 kg / m
When it is m ² , preferably 1 to 30 kg / mm ² , not only flexibility but also workability is favorable, which is desirable.

B comprising polyester B in the present invention
Addition of inert particles to the layer is effective in improving the slipperiness. Examples of the inert particles include inorganic compounds such as silicon oxide, aluminum oxide, zirconium oxide, calcium carbonate and magnesium carbonate, or infusible organic compounds such as crosslinked polystyrene, crosslinked divinylbenzene, benzoguanamine and silicone. Colloidal silica, pulverized silica, crosslinked polystyrene, silicone and the like are particularly preferable in terms of transparency. The particle size and the addition amount are not particularly limited, but in terms of slipperiness and transparency, the average particle size is 0.01 to 10 μm, preferably 0.1 to 5 μm, and the addition amount is 0.001 to 10 μm. %, Preferably 0.05 to 1% by weight. Further, the polyester A may also contain particles as long as the characteristics are not impaired. Furthermore, in the laminated film, polyester A and polyester B may be mixed to produce a laminated film in terms of raw material recovery.

The laminated polyester film of the present invention comprises:
Additives such as an antistatic agent, a heat stabilizer, an antioxidant, a crystal nucleating agent, a weathering agent, an ultraviolet absorber, a pigment and a dye can be used in each layer as long as the object of the present invention is not impaired. In addition, embossing, surface irregularity processing such as sand matting, corona discharge treatment, plasma treatment,
Surface treatment such as alkali treatment may be performed as necessary. Further, the flexible polyester film of the present invention is provided with an easy-adhesion treatment agent, an antistatic agent, a water vapor / gas barrier agent (such as polyvinylidene chloride), a release agent, an adhesive agent, an adhesive agent, a flame retardant agent, an ultraviolet absorber, and a matting agent It may be coated or printed with pigments, dyes, etc., and vacuum-deposited metals such as aluminum, aluminum oxide, silicon oxide, and palladium and their compounds for light shielding, water vapor / gas barrier, surface conductivity, and infrared reflection. However, the purpose and method are not limited to the above.

In the laminated polyester film of the present invention, the wetting tension on at least one side is 40 dyne / cm.
As described above, it is preferably 45 dyne / cm or more because the adhesive force is improved.

As a method for increasing the wetting tension, it is preferable to use polyester B having a high wetting tension or a method using corona discharge treatment.

The thickness of the film of the present invention is not particularly limited, but it is effectively used when it is 1 to 1000 μm, preferably 5 to 500 μm.

Next, a method for producing the film of the present invention will be described, but the invention is not limited thereto. Polyester A
And polyester B are melt extruded by separate extruders,
Two kinds of polymers are compound-extruded into a sheet shape by using a feed block or a manifold compound die, and are rapidly cooled and cast. As the casting method, an electrostatic applied casting method, a casting method through a water film, a calender casting method in which at least a pair of rolls are cooled and solidified while being pressurized, and the like are preferable.

The film of the present invention is excellent in flexibility, transparency and processability, and is used for industrial materials such as greenhouse materials and adhesive sheets, for packaging materials such as foods and pharmaceuticals, papers, woven fabrics, non-woven fabrics, foam materials and the like. It can be suitably used as a laminate with.

[0036]

EXAMPLES The present invention will be described in more detail with reference to examples. The characteristics in the examples were measured as follows. (1) Melt viscosity of polyester The polyester dried at 140 ° C for 8 hours was measured at 250 ° C using a melt index.

(2) Intrinsic viscosity of polyester Measured at 25 ° C. using o-chlorophenol as a solvent.

(3) Melting point (Tm), glass transition temperature (T
g) It measured using the differential scanning calorimeter DSC2 (made by Perkin-Elmer company). 28 mg of 10 mg sample under nitrogen stream
It was kept melted at 0 ° C. for 5 minutes, and then quenched with liquid nitrogen.
The specific heat change based on the transition from the glass state to the rubber state was read in the process of raising the temperature of the obtained sample at a rate of 10 ° C./min, and this temperature was taken as the glass transition temperature (Tg), and the endothermic peak temperature due to crystal melting was determined. The melting point (Tm) was used.

(4) Polyester composition analysis Polyester was hydrolyzed with an alkali to isolate an acid component and a glycol component, and each component was analyzed by gas chromatography or high performance liquid chromatography. From the peak area of each component, The composition ratio was determined.

(5) Film haze Regarding the film obtained from polyester, JIS-
The film haze was measured according to K-6714, and converted to 100 μm by the following formula. H ₁₀₀ (%) = H × 100 / d H: Measured value of haze (%) d: Film thickness of the haze measurement part (μm)

(6) Young's Modulus For films obtained from polyester, ASTM
-Young's modulus was measured according to -D-882-81 (A method).

(7) Adhesive strength PET film (thickness 15 μm) / urethane ink /
In the laminated polyester film, the adhesive strength of the ink / laminated polyester film was examined and judged as follows. Ink does not peel off: Class A, less than 10% of ink peels off: Class B, 10% or more of ink peels off: Class C

(8) Folding whitening property A vinyl chloride film and a laminated polyester film were adhered to each other, and the presence or absence of bending whitening when bent 90 degrees was examined.

Example 1 56 parts by weight of dimethyl terephthalate, 35 parts by weight of dimethyl ester of dimer acid having 36 carbon atoms, 56 parts by weight of 1,4-butanediol and 0.1 part by weight of tetrabutyl titanate as a transesterification reaction and polycondensation reaction catalyst. Was added to the mixture, and the transesterification reaction was performed according to a conventional method. Then, the polycondensation reaction was performed under a high temperature and reduced pressure to obtain a melt viscosity of 2000 pois.
e, a copolyester A shown in Table 1 having an intrinsic viscosity of 0.85 dl / g was obtained. The composition of the obtained polyester was 83 mol% of terephthalic acid residues, 17 mol% of dimer acid residues, and 100 mol% of 1,4-butanediol residues. On the other hand, polyester B has an intrinsic viscosity of 0.80 dl
/ G of polybutylene terephthalate was polymerized.

Polyester A and polyester B
Are melt-extruded by using different extruders, laminated so as to have B / A / B (laminating ratio 1: 48: 1) in the die, and extruded into a sheet to impart an electrostatic charge to the sheet. While applying, it was cast on a casting drum kept at 15 ° C. As shown in Table 1, the obtained film had a thickness of 100 μm, a Young's modulus of 16 kg / mm ² , and a wetting tension of 4
It was 2 dyne / cm, and transparency, adhesive strength, and bending whitening property were good.

Example 2 Polyester B and polybutylene terephthalate (B) and isophthalic acid 35 mol% copolymerized polybutylene terephthalate (B ') were used, except that a laminated film of B / A / B' was used. A film was formed in the same manner to obtain a film. As shown in Table 1, the obtained film was good in transparency, adhesive strength, and bending whitening property.

Example 3 Example 1 except that 20 mol% of dodecanedioic acid copolymerized polybutylene terephthalate was used as the polyester A.
A film was formed in the same manner as in 1. As shown in Table 1, the obtained film was slightly inferior in flexibility and flatness due to its polyester composition and viscosity, but was excellent in transparency, adhesive strength and bending whitening property.

Example 4 When the film of Example 1 was subjected to a single-sided corona discharge treatment,
As shown in Table 1, the wetting tension was 50 dyne / cm, and the adhesive strength was particularly good.

Comparative Examples 1 to 3 Each of the single-layer films shown in Table 1 was formed into a film in the same manner as in Example 1. All of the films deteriorated in properties such as adhesive strength and bending whitening property, and films satisfying all requirements were obtained. I couldn't get it. The polyester of Comparative Example 2 does not belong to the polyester A of the present invention, but is described in the column of polyester A in the table.

[0050]

[Table 1]

[0051]

The laminated polyester film of the present invention is
As described above, an aromatic dicarboxylic acid residue and an aliphatic dicarboxylic acid residue as the acid component, and a glycol component 1,
Polyester B having a 4-butanediol residue as a main constituent is laminated with polyester B having an aromatic dicarboxylic acid residue and a 1,4-butanediol residue as a main constituent, and not only flexibility but also It has excellent transparency, heat resistance and workability.

Claims (2)

[Claims] 1. A repeating unit constituting a polyester, wherein an aromatic dicarboxylic acid residue of 50 to 9 is used as an acid component.
5 mol% and aliphatic dicarboxylic acid residue 5 to 50 mol%
And a polyester B having a 1,4-butanediol residue as a main constituent as a glycol component, and a polyester B having an aromatic dicarboxylic acid residue and a 1,4-butanediol residue as a main constituent on at least one surface of the polyester A. A laminated polyester film characterized in that 2. At least one surface has a wetting tension of 40 dyn.
The laminated polyester film according to claim 1, wherein the laminated polyester film has an e / cm or more.