JPH0224213B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a composite film for preventing dew condensation, which is formed by providing a slippery, droplet-discharging resin layer made of a special copolyester ether on at least one side of a plastic film. [Prior Art] In recent years, forced cultivation of vegetables, fruits, and flowers has become widely practiced, and agricultural greenhouses have become rapidly popular.
Plastic films, which are lightweight, inexpensive, and easy to install, have come to be widely used as covering materials for agricultural greenhouses, especially plastic films that have been treated to be drip-proof to prevent fogging inside the greenhouse. This drip-proofing treatment can be applied to the film beforehand, or it can be applied by spraying from the inside after being spread on the house. on the other hand,
The strength and weather life of plastic films has also been improved, and films with a lifespan of two to several years or more have been developed. However, while this strength has a long weather resistance life, the drip-proof treatment has a short life, about one year at most. Especially during the cold winter months, many water droplets form on the inside of the film from night to early morning, but during the day when the sun rises, the skylight of the greenhouse is opened to adjust the temperature rise inside the greenhouse, so the film surface The water droplets evaporate and dry.
At this time, the film often became cloudy. A drawback of conventional films is that their drip-proof performance rapidly decreases as the process of forming water droplets and drying is repeated. [Object of the Invention] An object of the present invention is to eliminate the above-mentioned drawbacks, to provide a composite film that is free from clouding and maintains drip-proof performance over a long period of time. [Configuration of the Invention] The present invention has the following configuration to achieve the above object, that is, 60 mol% of the total dicarboxylic acid component is added to at least one side of the plastic film.
The above is aromatic dicarboxylic acid, 7 to 40 mol% is ester-forming sulfonic acid alkali metal salt compound, and of the total glycol component, 40 mol% or more is aliphatic or alicyclic glycol, and 1 to 60 mol% is A composite film comprising a copolyester ether resin layer made of diethylene glycol or triethylene glycol, and characterized in that the copolyester ether resin layer contains an inorganic colloid, a surfactant, and a polyether. It is. The plastic film used as the base material of the present invention may be a film made of polyethylene, polypropylene, polyvinyl chloride, polystyrene, polymethyl methacrylate, polycarbonate, polysulfone, etc., but polyester film is preferred from the viewpoint of mechanical properties. In particular, a biaxially stretched polyester film in which 85 mol% or more of the repeating units are ethylene terephthalate units is more preferably applied. Further, a composite film in which layers having weather resistance superior to that of the plastic film used as the base material are laminated, and a composite film whose weather resistance has been improved by surface treatment are also preferably used. For example, on the surface of a polyester biaxially stretched film with a drip-proof resin layer on the back side, polycarbonate, polysulfone, polyethylene-2,6-naphthalate, a condensation polymer made of terephthalic acid or isophthalic acid and a wholly aromatic dihydroxy compound, or fluorine-containing Laminated films such as polymers,
Alternatively, a composite film whose surface is surface-treated with an unsaturated fluorine compound or an inorganic compound to improve weather resistance is preferably used. The aromatic dicarboxylic acid component of the copolyester ether which becomes the resin layer of the present invention includes terephthalic acid, isophthalic acid, phthalic acid, 2,5-dimethylterephthalic acid, 1,4-naphthalene dicarboxylic acid, and 2,6-naphthalene dicarboxylic acid. Acid, biphenyldicarboxylic acid, 1,2-bis(phenoxy)ethane-P,P'-dicarboxylic acid, and ester-forming derivatives thereof are used. Although these may be used alone, a combination of two or more is preferred from the viewpoint of adhesion to the copolyester ether film, and a combination of terephthalic acid and isophthalic acid is particularly preferred. The isophthalic acid component is preferably in the range of 2 to 20 mol % of the aromatic dicarboxylic acid component, and in this range, the adhesion is higher and there is no blocking. At least 60 mol% of the dicarboxylic acid component constituting the polyester segment must be aromatic dicarboxylic acid and/or its ester-forming derivative, and if the aromatic dicarboxylic acid component is within this range, the copolyester ether film This is preferable because it increases the adhesion to the surface and improves the drip-proof effect. Examples of the ester-forming sulfonic acid alkali metal chloride 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 -Xylin glycol, 2
-Sulfo-1,4-bis(hydroxyethoxy)
Examples include alkali metal salts such as benzene (alkali metal salts of sulfonic acids) and ester-forming derivatives thereof, and 5-sulfoisophthalic acid, sodium sulfoterephthalic acid, and their ester-forming derivatives are more preferably used. The amount of these ester-forming sulfonic acid alkali metal salt compounds added is 7 to 40 mol%, preferably 10 to 20 mol%, based on the total dicarboxylic acid components.
It is. If it is less than 7 mol%, there is no drip-proof effect and it is not practical, and if it exceeds 40 mol%, the characteristics of the drip-proof effect will decrease and the melt viscosity will increase dramatically, so it is difficult to achieve the desired high temperature by melt polymerization. It is difficult to obtain a copolyester ether with a high degree of polymerization. When the amount added is 10 to 20 mol%, the best initial drip-proof properties and drip-proof durability can be obtained. Glycol components used in the present invention include:
Aliphatic or alicyclic glycols, such as ethylene glycol, 1,3-propanediol, 1,
4-butanediol, 1,4-cyclohexanedimethanol, etc. are preferred, but the glycol component further contains diethylene glycol or triethylene glycol in an amount of 1 to 60 mol%, preferably 2 to 18% by mole.
It is necessary to copolymerize mol%. In some cases, diethylene glycol and triethylene glycol may be used together. It is preferable that the copolymerization content of diethylene glycol or triethylene glycol is 1 mol % or more because it facilitates water solubilization of the copolyester ether and uniform application. On the other hand, it is preferable that the amount of copolymerized diethylene glycol or triethylene glycol is 60 mol % or less because blocking or whitening of the coating film does not occur after coating. The best drip-proofing effect and applicability can be obtained when the copolymerization content is 2 to 18 mol%. In addition, in the present invention, by adding an oxide colloid, hydroxide colloid, carbonate colloid, sulfate colloid, or metal colloid to the copolyester ether, blocking properties of the composite film can be prevented, and The drip-proof property can be further improved and the drip-proof property can be maintained for an extremely long period of time. The amount of this colloid added is preferably 1 to 50% by weight, more preferably 5 to 40% by weight, suitable for improving properties, and more than 1% by weight, more preferably 5 to 40% by weight.
At weight% or higher, the special effect of drip-proofing is excellent, and
When the amount is 50% by weight or less, more preferably 40% by weight or less, the film is less likely to become cloudy and has excellent transparency. The term "colloid" used in the present invention is defined in the Kyoritsu Shuppan Chemical Dictionary, and includes 10 ³ to 10 ⁹ atoms in one particle. Depending on the element, it can be obtained as a metal colloid, oxide colloid, or hydroxide colloid, but colloids that are finer than the wavelength of visible light are preferred to prevent clouding.
Metal colloids include gold, palladium, platinum,
Silver, sulfur, etc. are preferably used, and oxide colloids, hydroxide colloids, carbonate colloids, and sulfate colloids include zinc, magnesium, silicon, calcium, aluminum, strontium, barium, zirconium, titanium, manganese, iron, and cobalt. , nickel, tin oxide colloids, hydroxide colloids, carbonate colloids,
Sulfate colloids are preferably used. For example, a silicic acid colloid obtained by adding silicon tetrahalide to water or gradually adding concentrated hydrochloric acid to an aqueous solution of an alkali silicate is more preferably used. Any type of surfactant can be used, including cationic, anionic, amphoteric, and nonionic types, but anionic types are particularly preferred, such as sodium dodecylbenzenesulfonate and sodium dodecylxylenesulfonate. These include alkylbenzenesulfonates, alkylnaphthalenesulfonates, and alkylphenolsulfonates. Among them, sodium dodecylbenzenesulfonate is preferred. The preferred content is 0.5 to 5% by weight. Furthermore, the copolyester ether resin layer in the present invention contains polyether in order to prevent water droplets from becoming cloudy when they dry and to maintain a drip-proof effect against repeated wetting and drying over a long period of time. It is necessary. The term "polyether" as used herein refers to a parent polymer having an ether bond as its main bond chain, and particularly preferred are aliphatic polyethers, such as polyethylene glycol, polypropylene oxide, glycerin ether, and polyethylene glycol monoethyl ether. etc. Among them, polyethylene glycol is preferred. Polyethylene glycol is H(-OCH ₂ CH ₂
) - _o OH (in the formula, n is an integer from 2 to 240), and the preferred range of its molecular weight is 200
-10000, more preferably 300-5000, even more preferably 500-2000. If it is smaller than this range, the drip-proof property will not last long enough, and if it is larger than this range, when the film's drip-proof surface dries, it will become cloudy and the light transmittance will decrease. The preferred content of polyether is 1.5 to 30% by weight,
More preferably, it is 3 to 15% by weight. If the amount is less than this range, the film surface tends to become cloudy, and if it is more than this range, the film is likely to block when wound. The polyether is copolymerized or blended with the copolyester ether resin layer, but it is preferable to blend it in order to maintain the drip-proof effect. Next, a method for manufacturing the composite film of the present invention will be explained. A biaxially stretched polyester film, which is a typical example of laminating the copolyester ethers of the present invention, is produced by applying a predetermined amount of the above copolyester ether aqueous solution to a basic unstretched polyester film, and then biaxially stretching the film sequentially or simultaneously. , A basic unstretched polyester film is stretched in one direction in advance, and a predetermined amount of the block polyester ether is coated with hot melt, extrusion, or an aqueous solution, and then stretched in a direction perpendicular to the primary stretching direction. A method of applying a predetermined amount of the block polyester ether to a base biaxially stretched polyester film by hot melt, extrusion, or coating with an aqueous solution and then drying the polyester biaxially stretched film. It can be obtained by spraying the above copolyester ether on the greenhouse before or after the spreading work. Note that the method for synthesizing polyethylene terephthalate or the like can be directly applied to the synthesis of the copolyester ether. Furthermore, pigments, dyes, antioxidants, ultraviolet absorbers, etc. may be added to the copolyester ether drip-proof resin layer of the present invention, if necessary. [Effects of the Invention] The effects of the present invention are summarized as follows. Excellent drip-proof performance can be maintained over a long period of time. Even if the drip-proof surface is repeatedly turned into water droplets and dried, the drip-proof performance does not deteriorate and there is no clouding. The drip-proofing agent has excellent applicability and can form a uniform resin layer. In addition to agricultural greenhouses, the film of the present invention can be used in a wide range of applications, including solar collectors, photo-selective membranes, traffic signs, packaging materials for fruits and vegetables, meat, fish and meat, coating materials for freezers such as ice cream, automobiles, and interior materials for houses. used. The present invention will be described in more detail with reference to Examples below, but 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. (1) Drip-proof performance and cloudiness; small house (5 cm on the floor)
A film is installed on the roof of a greenhouse at an angle of 30 degrees from the horizontal to store water at a height of Performance was evaluated, and for the next 12 hours, the outside temperature was kept at 30°C and the ridges were opened to dry the film surface, and the degree of clouding of the film surface was evaluated, and this process was repeated for 100 days. (2) Blocking property; at 40℃, 80-90%RH,
Blocking property after applying a load of 119 kg/125 cm ² and leaving it for 5 days. (3) Indication of judgment criteria: ○: Good △: Slightly poor ×: Bad Example 1 150 parts of dimethyl terephthalate, 15 parts of dimethyl isophthalate, 44.5 parts of dimethyl 5-sodium sulfoisophthalate, 124 parts of ethylene glycol, manganese acetate 0.106 parts of tetrahydrate and 0.07 parts of calcium acetate dihydrate were mixed, methanol was distilled off at 140 to 220°C, transesterification was carried out, and then 0.09 parts of trimethyl phosphate and 7.2 parts of diethylene glycol were mixed.
1 part, add 0.06 part of antimony trioxide, and heat from 240℃.
The temperature was raised to 280°C over 1 hour and 30 minutes, and the pressure was gradually lowered from normal pressure to 0.5 mmHg to remove the generated ethylene glycol from the system, and this state was maintained for an additional 40 minutes to react, [η] = 0.57 obtained a polymer. Analysis of the copolymerization components of the polyester ether produced revealed that the diethylene glycol component was 17 mol% of the total diol component, including by-products during the reaction, and the 5-sodium sulfoisophthalic acid component was 14 mol% of the total dicarboxylic acid component. It was contained. The obtained copolyester ether was dissolved in hot water at 85°C to form a 5% by weight aqueous solution. Concentration in this
A 20% colloidal silica aqueous solution, sodium dodecylbenzenesulfonate, and polyethylene glycol with a molecular weight of 1000 are added, and the composition ratio of the solids is 67% by weight of copolyester ether, 25% by weight of colloidal silica, and 1% by weight of sodium dodecylbenzenesulfonate. % by weight and 7% by weight of polyethylene glycol. On the other hand, polyethylene terephthalate was melt-extruded at 290°C and cast onto a cast drum at 20°C by electrostatic application to form a non-stretched sheet, which was then stretched 3.3 times in the longitudinal direction by roll stretching. After applying the drip-proof agent aqueous solution to this uniaxially stretched film, it was stretched 3.5 times in the width direction at 95°C, and heat-treated at 210°C while slightly loosening, and a drip-proof layer of 0.3μ was laminated on the polyethylene terephthalate base. A composite film of 100μ was obtained. When the resulting composite film was spread in an agricultural greenhouse with the drip-proof layer on the inside, there was no clouding at all.
Drip-proof performance is good on days when the temperature is low from December to February, and even when the skylight is opened to dry water droplets during the day when the temperature rises, the film surface does not become cloudy and transparency is good. It was hot. Even after 2 years of continued use, it maintained its drip-proof performance and did not become cloudy when drying. Example 2 An aqueous solution containing 5% by weight of the copolyester ether shown in Table 1 and various colloidal compounds was applied to the polyethylene terephthalate uniaxially stretched film obtained by the method of Example 1, and the film was stretched 3.5 times in the width direction by a conventional method. Thereafter, heat treatment was performed to obtain a coated biaxially stretched polyethylene terephthalate film with a coating thickness of 0.3 microns. 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 7 corresponded to the present invention, and the blocking property, drip-proof performance, and clouding were also good. Experiment No.
Examples 8 to 10 are comparative examples that are outside the scope of the present invention and have defects in some of the characteristics.

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Claims (1)

[Claims] 1. On at least one side of the plastic film,
Of the total dicarboxylic acid components, 60 mol% or more are aromatic dicarboxylic acids, 7 to 40 mol% are ester-forming sulfonic acid alkali metal salt compounds, and of the total glycol components, 40 mol% or more are aliphatic or fatty acids. A composite film comprising a copolyester ether resin layer in which 1 to 60 mol% of the cyclic glycol is diethylene glycol or triethylene glycol, and the copolyester ether resin layer contains an inorganic colloid, a surfactant, and a polyether. A composite film characterized by containing: