JPH0422695B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention provides a polyester film containing terephthalic acid as the main acid component, which has drip-proof properties on at least one side.
The present invention relates to a polyester film provided with a water-soluble polyester resin layer having excellent antifogging properties. [Prior art and its problems] In recent years, forced cultivation of vegetables, fruits, and flowers has become widespread, and agricultural greenhouses have become rapidly popular. These agricultural greenhouses generally have a frame made of iron, aluminum, wood, bamboo, etc., and are covered with glass, plastic board, plastic film, etc., which have good light transmittance. Plastic films such as polyethylene film or vinyl chloride film are commonly used as covering materials because they are light, inexpensive, and easy to install; however, these plastic films are inferior in strength and other mechanical properties. ,
In recent years, polyester films, particularly polyester films containing terephthalic acid as a main component, have come into use. However, since polyester film generally has low hydrophilicity, when applied to agricultural greenhouses, moisture within the greenhouse and in the air forms numerous droplets and adheres to the film surface due to transpiration and temperature changes. . For this reason, there are problems such as a decrease in the transmittance of sunlight, or a so-called whitening phenomenon in which the surface of the film becomes cloudy due to aging. Conventional methods for imparting drip-proof and anti-fog properties to films in agricultural applications include kneading anti-fog and drip-proof substances into the film during film forming, or applying solutions containing anti-fog and drip-proof substances to the film surface. has been adopted. However, although these methods have good initial anti-fog and drip-proof properties, they have drawbacks such as poor durability when used for a long period of time. The present inventors have arrived at the present invention as a result of extensive studies aimed at eliminating the drawbacks of the conventional polyester films described above. [Object of the Invention] An object of the present invention is to provide a polyester film suitable for use in agricultural greenhouses, etc., which has excellent anti-fog and drip-proof properties over a long period of time. [Structure of the Invention] The object of the present invention is to provide at least one side of a film made of polyester containing terephthalic acid as the main acid component, in which 40 mol% or more of the total dicarboxylic acid components are aromatic dicarboxylic acid components, and 10 to 40 mol%.
is an ester-forming sulfonic acid alkali metal salt compound, 5 to 40 mol% is an alicyclic dicarboxylic acid component, and 70 mol% or more of the total glycol component is an aliphatic or alicyclic glycol component, 1 to 30 mol%. is polyethylene glycol H-(OCH ₂ CH ₂ ) _o -OH
This can be achieved by using a polyester film provided with a copolyester resin layer consisting of (where n is an integer of 2 to 150). The polyester film containing terephthalic acid as a main component, which is the base material of the invention, is preferably a biaxially stretched polyester film in which at least 80 mol% of the constituent units are ethylene terephthalate units. Examples of the aromatic dicarboxylic acid component of the copolyester which becomes the resin layer of the present invention include terephthalic acid, isophthalic acid, phthalic acid, 2,5-dimethylterephthalic acid, 1,4-naphthalene dicarboxylic acid, 2,6-
naphthalene dicarboxylic acid, biphenyl dicarboxylic acid, 1,2-bis(phenoxy)ethane-P,
P′-dicarboxylic acids and their ester-forming derivatives are used, and non-aromatic dicarboxylic acid components include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid and their ester-forming derivatives. is used. The dicarboxylic acid component constituting the polyester segment must contain at least 40 mol% of aromatic dicarboxylic acid and/or its ester-forming derivative;
If it is less than 40 mol%, it is not preferable because the adhesion of the copolyester to the polyester film and the long-term drip-proof properties are reduced. Examples of the ester-forming sulfonic acid alkali metal salt compounds constituting the resin layer of the present invention include sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, and sulfo-P- xylylene glycol,
Examples include alkali metal salts (alkali metal salts of sulfonic acid) such as 2-sulfo-1,4-bis(hydroxyethoxy)benzene and ester-forming derivatives thereof; 5-sulfoisophthalic acid,
More preferably, sodium sulfoterephthalic acid and ester-forming derivatives thereof are used. The amount of these ester-forming sulfonic acid alkali metal salt compounds added is 10 to 40 mol%, preferably 15 to 35 mol%, based on the total dicarboxylic acid components.
It is. If it is less than 10 mol%, the water solubility of the copolyester is low and the drip-proof property is low, making it impractical; if it exceeds 40 mol%, the durability of the drip-proof property decreases, and the anti-fogging property of the coated surface decreases. descend. Furthermore, since the melt viscosity increases dramatically, it is difficult to obtain a desired copolyester with a high degree of polymerization by melt polymerization.
When the amount added is 15 to 35 mol%, it exhibits the best initial drip-proofing properties, anti-fogging properties, and long-term sustainability. Examples of the alicyclic dicarboxylic acids constituting the resin layer of the present invention include 1,1-cyclopropanedicarboxylic acid, 1,2-cyclobutanedicarboxylic acid, and 1,2-cyclobutanedicarboxylic acid.
-Cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,2-cyclopentanedicarboxylic acid and their ester-forming derivatives, etc.; Ester-forming derivatives of are more preferably used. The amount of these alicyclic dicarboxylic acids added is 5 to 40 mol%, preferably 7 to 30 mol%, and more preferably 10 to 20 mol% based on the total dicarboxylic acids. If the amount is less than 5 mol %, the long-term sustainability of drip-proof and anti-fogging properties will decrease, and good solubility of the copolyester in water will not be obtained. If it exceeds 40 mol%, the antifogging property will be significantly reduced. Addition amount is 10~
When the amount is 20 mol %, the copolyester has the best water solubility, drip-proofing properties, and fog-proofing properties. Aliphatic or alicyclic glycol components used in the present invention include ethylene glycol, 1,2-
Propanediol, 1,3-propanediol,
1,4-butanediol, 2,4-dimethyl-2
-ethylhexane-1,3-diol, neopentyl glycol, 1,6-hexanediol,
Examples include 1,2 cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,3-cyclobutanol, and especially ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,4-cyclohexanedimethanol. etc. are preferably used. Furthermore, the glycol component is diethylene glycol, triethylene glycol or H-
(OCH ₂ CH ₂ ) _o -OH (in the formula, n is an integer of 4 to 150) polyethylene glycol is contained in an amount of 1 to 30 mol%, preferably 2 to 20 mol% based on the total glycol component.
Copolymerize by mole%. Two or more of these glycol compounds may be used in combination. Diethylene glycol, triethylene glycol or H-
(OCH ₂ CH ₂ ) _o -OH (in the formula, n is an integer from 4 to 150) added amount of polyethylene glycol is 1
If it is less than mol %, the solubility of the copolyester in water decreases, and the long-term antifogging property decreases. On the other hand, if the amount added exceeds 30 mol %, problems such as blocking of the coated film after application and a decrease in antifogging properties will occur. When the amount added is 2 to 20 mol%, the copolyester has the best water solubility and antifogging properties,
Provides good applicability. A biaxially oriented polyester film, which is a typical example of laminating the copolyesters of the present invention, is produced by applying a predetermined amount of the above copolyester aqueous solution to a basic unstretched polyester film and biaxially stretching the film sequentially or simultaneously. A method in which an unstretched polyester film is stretched in one direction in advance, and a predetermined amount of the copolyester is coated with hot melt, extrusion, or an aqueous solution, and then stretched in a direction perpendicular to the primary stretching direction. , hot-melt a predetermined amount of the copolyester onto a basic biaxially stretched polyester film,
It can be obtained by applying an extrusion or by applying an aqueous solution and drying it, or by spraying the above copolyester before or after stretching the basic biaxially stretched polyester film into an agricultural greenhouse. Note that the method for synthesizing polyethylene terephthalate, etc., can be applied directly to the synthesis of copolyesters.
Heating to 140-240℃, distilling off the methanol produced to carry out the transesterification reaction, then adding a normal polymerization catalyst and a coloring inhibitor such as a phosphorus compound, and heating at 200-290℃ for 0.01-50mm.
Method of polycondensation by distilling off ethylene glycol under reduced pressure of Hg, dicarboxylic acid and glycol at 150-270℃
It is obtained by a method of reacting under normal pressure or increased pressure, esterifying while distilling off the water produced, and polycondensing by adding diethylene glycol or the like. As the catalyst, one or more of conventional transesterification catalysts such as metal compounds such as Mg, Mn, Co, Ca, Zn, Sn, Ti, and Li can be used.
As the polymerization catalyst, for example, one or more of Sb, Ge, Ti, etc. can be used. Furthermore, pigments, dyes, antioxidants, ultraviolet absorbers, lubricants, antistatic agents, and the like may be added to the copolyester resin layer of the present invention, if necessary. It may be added during the synthesis of the copolyester, or it may be kneaded in when the copolyester is coated on a polyester film, or it may be added into an aqueous solution when the copolyester is water-solubilized and coated. [Effects of the Invention] The effects of the present invention are summarized as follows. Prevents water droplets from adhering to the film surface and does not impede transmission of incident light. Can maintain drip-proof properties for a long period of time. The transparency of the film is good, and there is no decrease in transparency or shedding of the drip-proof resin layer even after aging, and the anti-fogging property is also good. The drip-proofing agent has excellent applicability and can form a uniform resin layer. In addition to being used for agricultural greenhouses, the film of the present invention can also be used for solar collectors, photo-selective membranes, traffic signs, food packaging materials for fruits and vegetables, and meat, as well as for metal deposition, drafting, magnetic tape, etc. due to its excellent adhesive properties. used as the raw material for This will be explained in more detail by giving examples below.
The present invention is not limited to these examples. Note that parts in the examples indicate parts by weight. The evaluation criteria were determined based on the following. A. Solubility in hot water: State when dissolved in hot water at 80-90°C for 1 hour. B. Coatability The state when an aqueous solution of various copolyesters is applied to a uniaxially stretched polyethylene terephthalate film using a gravure roll. C Drip-proof property Initial drip-proof property when a film is installed on the roof of a small house (water stored at a height of 5 cm on the floor) at an angle of 30 degrees from the horizontal plane and kept at 40°C, after 30 days. Shows drip-proof properties. D. Anti-fog property Determine the degree of whitening before and after the drip-proof test in Section C above. Criteria for each item A to D ○: Good △: Slightly poor ×: Poor E Intrinsic viscosity [η] Measured with O-chlorophenol at 25°C Example 1 Dimethyl terephthalate 116 parts, 5-sodium dimethyl sulfoisophthalate 89 parts, 20 parts of dimethyl 1,4-cyclohexanedicarboxylate, 118 parts of ethylene glycol, 5.3 parts of diethylene glycol,
Mix 0.12 parts of manganese acetate tetrahydrate and 0.14 parts of calcium acetate dihydrate, distill off methanol at 140 to 230°C, perform a transesterification reaction, and then add 0.09 parts of trimethyl phosphate and 0.06 parts of antimony trioxide. was added, the temperature was raised from 240℃ to 280℃ over 1 hour, and the pressure was gradually lowered from normal pressure to 0.5mmHg to remove the generated ethylene glycol from the system, and this state was maintained for another 1 hour to react. A polymer with η]=0.32 was obtained. Analysis of the copolymer components of the produced polyester ether revealed that the diethylene glycol component contained 12 mol% of the total diol components, including by-products during the reaction. The obtained copolyester was dissolved in hot water at 85°C to form a 5% by weight aqueous solution. On the other hand, polyethylene terephthalate was melt-extruded at 290°C, cast onto a cast drum at 20°C to which electrostatic charge was applied, and a non-stretched sheet was obtained.The unstretched sheet was then stretched 3.3 times in the longitudinal direction by roll stretching. After applying the drip-proof copolyester aqueous solution to this uniaxially stretched film, it was heated at 95°C in the width direction.
Stretched 3.5 times and then heat treated at 210℃ to form a drip-proof layer
A 100μ film based on polyethylene terephthalate laminated with 0.3μ was obtained. When agricultural greenhouses were made using the obtained film with a drip-proof layer on the inside, it was found that there was no clouding at all and that it maintained extremely excellent drip-proof properties even after 12 months, and also maintained its transparency. . Example 2 A 5% by weight aqueous solution of the copolyester shown in Table 1 was applied to the polyethylene terephthalate uniaxially stretched film obtained by the method of Example 1, and the film was spread in the width direction using a conventional method.
After stretching 3.5 times, it was heat treated to obtain a coated biaxially stretched polyethylene terephthalate film with a coating thickness of 0.3μ. The evaluation results for this film are shown in Table 1. As is clear from Table 1, the evaluation results were as follows: Experiment Nos. 1 to 5 corresponded to the present invention, and the hot water solubility, drip-proofing properties, and anti-fogging properties were also good. Experiments Nos. 6 to 11 are comparative examples outside the scope of the present invention, and have defects in some characteristics. 【table】

Claims (1)

[Claims] 1. On at least one side of a film made of polyester having terephthalic acid as the main acid component, 40 mol% or more of the total dicarboxylic acid components is an aromatic dicarboxylic acid component, 10 to 40 mol% is an ester-forming sulfonic acid alkali metal salt compound, 5 to 40 mol% is alicyclic dicarboxylic acid component, 70 mol% or more of all glycol components is aliphatic or alicyclic glycol component, and 1 to 30 mol% is polyethylene glycol H-(OCH ₂ CH ₂ ) A polyester film provided with a copolyester resin layer consisting of _o -OH (in the formula, n is an integer from 2 to 150).