JP2003334905A - Easily adhesive stretched film of syndiotactic polystyrene - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easily adhesive stretched film of a syndiotactic polystyrene which shows excellent adhesive properties between a film and an adhesive modified layer, and has excellent economical efficiency, recycling properties and environmental adaptability during manufacturing. <P>SOLUTION: This easily adhesive stretched film of a syndiotactic polystyrene is obtained by laminating an adhesiveness modified layer formed of a water- dispersible copolymer polyester with a glass transition temperature of 30°C or lower, on at least one side of the stretched film composed of a styrene polymer substantially having a syndiotactic structure. Especially the adhesiveness modified layer is preferably formed by applying an aqueous dispersion of a copolyester to an unstretched film or a uniaxially stretched film, and uniaxially or biaxially orienting the film once or more before thermally treating it. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a syndiotactic polystyrene stretched film, and more particularly to an easy-adhesion syndiotactic polystyrene stretched film having excellent adhesion between the film and the adhesion-modifying layer.

[0002]

2. Description of the Related Art Stretched syndiotactic polystyrene films are excellent in tearability, heat resistance, electrical properties, transparency, etc., and are used in various film applications such as magnetic tapes, photo / plate making, capacitors, and packaging. Is expected to be deployed.

In particular, when a film is used as a packaging material, a printed layer, a gas barrier layer formed by coating and laminating an organic polymer, a gas barrier layer formed by vapor deposition of an inorganic or metal, etc. are generally provided on at least one side of a stretched film, if necessary. Is laminated, and an adhesive is further laminated on the laminated body, and a sealant layer or the like is provided by a dry laminating method or an extrusion laminating method, and a bag is produced using the laminated body. Parts are heat-sealed to provide hermetically sealed food products, medicines, and miscellaneous goods to general consumers. Therefore, in order to form the above-mentioned laminate, the stretched film is provided with a physical treatment such as corona treatment or an adhesiveness-modifying layer in order to obtain sufficient adhesiveness with the printing layer, the gas barrier layer, the sealant layer, or the like. Is generally done.

Also in the case of a syndiotactic polystyrene type stretched film, in JP-A-5-338089, the surface of the film is subjected to corona treatment to increase the surface tension, and then an anchor coating agent is applied and a sealant layer is formed thereon. It is disclosed to provide. However, in the case of corona discharge treatment, there is a problem that the film after treatment tends to be semi-permanently charged and workability is deteriorated, and the adhesiveness is not sufficient. JP 20
No. 00-6330 discloses that an adhesion modifying layer comprising a self-crosslinking polyester-based graft copolymer is laminated on a syndiotactic polystyrene-based stretched film in order to enhance adhesion with a gas barrier layer or a sealant layer. Is disclosed. However, since the adhesion modifying layer is a crosslinkable polymer, this film is difficult to remelt and extrude,
There was a problem with recyclability.

On the other hand, providing a modified layer for improving slipperiness and abrasion resistance on a syndiotactic polystyrene stretched film by a coating method is disclosed in JP-A-3-109453 and JP-A-3-109454, JP 8-39741 JP, JP 8-480
Although disclosed in JP 08, JP 2000-6330 A, etc., the adhesiveness between the modified layer and the film used cannot be said to be sufficient.

[0006]

In the case of the syndiotactic polystyrene stretched film, it was difficult to provide a satisfactory adhesion modifying layer. For example, when a conventional water-based coating agent is used, sufficient adhesion between the film and the adhesion-modifying layer cannot be obtained because the surface of the film has properties such as low surface energy and high crystallinity. . on the other hand,
It is not preferable to use the solvent-based coating agent from the viewpoint of environmental pollution and occupational health of workers.

An object of the present invention is to provide a laminated syndiotactic polystyrene type stretched film which is excellent in adhesion between the film and the adhesion modifying layer. Further, it is an object of the present invention to provide an easily-adhesive syndiotactic polystyrene stretched film which is excellent in economical efficiency, recyclability, and environmental compatibility at the time of production.

[0008]

Means for Solving the Problems As a result of earnest studies, the inventors of the present invention have described above by laminating an adhesive modification layer composed of a specific water-dispersible copolyester on at least one surface of the film. I was able to achieve my purpose. That is, the present invention provides an adhesive property-improving layer composed of a water-dispersible copolyester having a glass transition point of 30 ° C. or lower on at least one surface of a stretched film composed of a styrene-based polymer having a substantially syndiotactic structure. It is a laminated easy-adhesive syndiotactic polystyrene-based stretched film. In a further preferred embodiment, the adhesion-improving layer composed of the water-dispersible copolyester is a styrene-based polymer having a syndiotactic structure in an aqueous coating solution containing the water-dispersible copolyester. It is an easily-adhesive syndiotactic polystyrene-based stretched film that is formed by applying it to an unstretched film or a uniaxially stretched film, then stretching it in the uniaxial or biaxial direction one or more times, and then heat treating it.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The styrenic polymer having a syndiotactic structure of the present invention has a tacticity in which a phenyl group or a substituted phenyl group of a side chain as a syndiotactic structure is quantified by a nuclear magnetic resonance method. 85% or more of (two constitutional units) and 50% or more of pentad (five constitutional units) of syndiotactic structure polystyrene, poly (p-, m- or o-methylstyrene), poly (2 , 4-, 2,5-, 3,4- or 3,5-dimethylstyrene), poly (p-tertiarybutylstyrene) and other poly (alkylstyrenes), poly (p-, m- or o-chloro) Poly (halogenated styrene) such as styrene), poly (p-, m- or o-bromostyrene), poly (p-, m- or o-fluorostyrene), poly (o-methyl-p-fluorostyrene) , Poly (p-, m- or o-chlorome Polystyrene (eg halogen-substituted alkyl styrene), poly (p-, m- or o-methoxy styrene), poly (p-, m- or o-ethoxy styrene), poly (alkoxy styrene), poly (p -, M- or o-carboxymethylstyrene) such as poly (carboxyalkylstyrene), poly (p-vinylbenzylpropyl) such as poly (alkyl ether styrene), poly (p-trimethylsilylstyrene) such as poly (alkylsilyl) Examples thereof include styrene), and poly (vinylbenzyldimethoxyphosphide). Particularly, syndiotactic polystyrene is suitable.

The styrene-based polymer having a substantially syndiotactic structure of the present invention does not necessarily have to be a single compound, and may be a mixture with a polystyrene-based polymer having an atactic structure or an isotactic structure, or a copolymer. It may be a combination or a mixture thereof, but at least 40% by weight or more is composed of a styrene polymer having a syndiotactic structure.

The syndiotactic polystyrene polymer of the present invention has a weight average molecular weight of 10,000 or more, more preferably 50,000 or more. Weight average molecular weight is 10,0
If it is less than 00, a biaxially stretched film having excellent strength and elongation characteristics and heat resistance cannot be obtained. The upper limit of the weight average molecular weight is not particularly limited, but 1500,000
The above is not preferable because the load of the extruder increases and breakage occurs due to the increase of the drawing tension.

The syndiotactic polystyrene polymer of the present invention contains various known additives such as lubricants, pigments, heat stabilizers, antioxidants, antistatic agents, etc. within a range that does not impair the effects of the present invention. An impact resistance improver or the like may be added. As a lubricant, silica, titanium dioxide, talc, metal oxides such as kaolinite, calcium carbonate,
Examples include particles that are inert to syndiotactic polystyrene-based polymers, such as particles made of metal salts such as calcium phosphate and barium sulfate, or organic polymers.
One of the above lubricants may be used alone, or two or more thereof may be used in combination.

The syndiotactic polystyrene stretched film of the present invention can be manufactured by a known method. For example, a sequential biaxial stretching method in which a non-stretched film obtained by melt-extruding a syndiotactic polystyrene-based resin into a film from a die and cooling and solidifying the film is subjected to longitudinal stretching and transverse stretching in order can be applied. In addition to these, transverse / longitudinal sequential biaxial stretching method, longitudinal / transverse / longitudinal sequential stretching method, longitudinal / longitudinal / transverse sequential stretching method, and the like, simultaneous biaxial stretching method in which longitudinal stretching and transverse stretching are simultaneously performed, etc. Can be adopted, and the stretching method can be selected according to various properties such as required strength and dimensional stability. A uniaxially stretched film obtained by a longitudinal uniaxial stretching method or a lateral uniaxial stretching method may be used. As the stretching device, a roll stretching machine,
A tenter stretching machine, an inflation stretching machine or the like can be used. In addition, it is preferable that the stretched film is subjected to heat treatment such as heat setting treatment, longitudinal relaxation treatment, and transverse relaxation treatment, since thermal dimensional stability and adhesiveness are improved.

As a method for providing the syndiotactic polystyrene type stretched film with the adhesion modifying layer composed of the water dispersion type copolyester, for example, an aqueous type coating solution containing the water dispersion type copolyester is used as an unstretched film or Examples include a method (in-line coating method) of coating and drying on a uniaxially stretched film, then stretching the film uniaxially or biaxially one or more times, and then heat treating the film. Further, an aqueous coating solution containing a water-dispersible linear polyester may be applied and dried inline or off-line on the stretched / heat-treated film. The in-line coating method is preferable in that it can be manufactured at low cost and that the adhesion between the film and the adhesion modifying layer is improved. As a coating method, a known coating method can be applied, and examples thereof include a roll coating method, an air knife method, and a bar coating method.

The water dispersibility of the water-dispersible copolyester of the present invention means a polyester that is soluble or dispersible in an aqueous coating liquid having a water content of 20% by weight or more. The main component of the aqueous coating liquid is, for example, an alkaline aqueous solution, an acidic aqueous solution, an organic solvent, water containing a surfactant, or the like. The water dispersibility of the linear polyester is exhibited, for example, by introducing a hydrophilic group into the main chain of the polyester. As the hydrophilic group, -NH ₂ group, -OH group, -CO ₂ M group,
—SO ₃ M group (M is hydrogen, group I, II, III elements of the periodic table, cations such as ammonium) and the like.

The glass transition temperature of the water-dispersible copolyester in the present invention is required to be 30 ° C. or lower, more preferably 10 ° C. or lower. By using the water-dispersed copolyester having a glass transition temperature of 30 ° C. or lower, the adhesion between the syndiotactic polystyrene film and the adhesive property-modifying layer is significantly improved.

Since the adhesive property-modifying layer has sufficient adhesiveness to printing ink and anchoring agent for sealant laminating, in a laminate having an ink layer or a laminate layer on the adhesive property-modifying layer side, a synergistic effect is obtained. It is possible to improve the adhesion between the tactic polystyrene-based stretched film and the ink layer or sealant layer.

The water-dispersed copolyester of the present invention is
It is possible to polymerize from a dicarboxylic acid and / or a derivative thereof and a diol and / or a derivative thereof, and / or an oxycarboxylic acid and / or a derivative thereof by a known method,
Examples of the method for obtaining the water-dispersible copolyester having a glass transition temperature of 30 ° C. or lower include a method of appropriately setting the types and ratios of the aliphatic dicarboxylic acid and the aromatic dicarboxylic acid in the dicarboxylic acid component. For example, a diol having 2 to 6 carbon atoms as a main component of a diol, and an aliphatic dicarboxylic acid component as a total dicarboxylic acid component of 3
There may be mentioned a method of copolymerizing 0 to 100 mol% and an aromatic dicarboxylic acid component at a ratio of 70 to 0 mol% of all dicarboxylic acid components.

Examples of the aliphatic dicarboxylic acid component include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, dimer acid and 1,4-cyclohexanedicarboxylic acid. In the present invention, the alicyclic dicarboxylic acid is included in the aliphatic dicarboxylic acid. Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid.

As the diol, ethylene glycol,
1,4-butanediol, neopentyl glycol, 1,4-
Cyclohexanedimethanol, diethylene glycol,
Examples thereof include triethylene glycol, polyethylene glycol and polyetramethylene glycol. Also,
An oxycarboxylic acid component such as oxycaproic acid may be copolymerized.

As the monomer having a hydrophilic group for imparting water dispersibility, 5-sulfoisophthalic acid metal salt,
Examples thereof include, but are not limited to, metal salts of sulfoterephthalic acid.

As the raw material monomer of the water-dispersible copolyester of the present invention, a monomer having three or more functional groups in the molecule may be used, but the dicarboxylic acid will deteriorate the recyclability of the laminated film. It is preferably 3 mol% or less based on the total number of moles of acid and diol.

As a method for obtaining a dispersion of a water-dispersed copolyester, for example, a method of dispersing it in water together with a polar solvent can be mentioned. For example, the polyester and the polar solvent are premixed at 50 to 200 ° C, and water is added to the mixture while stirring, or the polyester, the polar solvent, and water are coexisted and stirred at 40 to 120 ° C to disperse the mixture. The method of doing is mentioned. As a polar solvent, alcohol-based,
Examples thereof include ester type, ketone type and amide type solvents. Further, instead of the polar solvent, a surfactant such as sodium alkylbenzene sulfonate, sodium alkylnaphthalene sulfonate, sodium alkyl sulfonate, sodium alkyl ether sulfonate can be used. The polar solvent and the surfactant can be used alone or in combination as a mixed solvent. The aqueous dispersion of polyester dispersed by the above method can be further diluted with water or a mixed solution of water and a polar solvent to prepare an aqueous coating solution for a film. Examples of the polar solvent for dilution include alcohols such as ethyl alcohol and isopropyl alcohol. The concentration of water in the coating liquid when applied to the film is preferably 20% by weight or more, more preferably 5% by weight from the viewpoint of industrial hygiene and the risk of fire and explosion.
It is 0% by weight or more.

The thickness of the adhesion modifying layer of the present invention is 0.01
μm to 5 μm, preferably 0.05 μm to 1 μm
Is. If the thickness of the adhesion modifying layer is too thin, sufficient adhesion cannot be obtained. If the thickness of the adhesion-modifying layer is too large, it is not economical because it requires unnecessary extra coating agent and drying equipment. In addition, the adhesiveness may be deteriorated, which is not preferable.

The water-dispersed copolyester of the present invention is
Although it is possible to form the adhesiveness-modifying layer alone, general-purpose polyester resins, urethane resins, acrylic resins, for other purposes,
Adhesion modifying layer by mixing those copolymers, various water-dispersed resins and various functional resins, for example, conductive resins such as polyaniline and polypyrrole, antibacterial resins, ultraviolet absorbing resins and gas barrier resins. May be formed.
Further, the adhesion modifying layer may contain additives such as an antistatic agent, an inorganic lubricant, an organic lubricant, and an ultraviolet absorber within a range that does not impair the effects of the present invention.

The adhesive property-improving layer of the present invention has excellent adhesiveness with the syndiotactic polystyrene stretched film, and also has sufficient adhesiveness with printing ink, sealant laminating anchor agent, etc. When a laminate having an ink layer or a laminate layer on the property-modifying layer side is produced, the laminate strength and seal strength of the laminate are significantly improved.

[0027]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The characteristics shown in the examples are measured and evaluated by the following methods.

(1) Glass transition temperature of water-dispersed copolyester First, a gauze washed with clear acetone and dried was prepared, and acetone was attached to the gauze to scrape off the adhesive modified layer of the film. Soxhlet extraction from the gauze under the following conditions, and a sample in which the adhesion improving layer was separated and dried to dryness was measured by DSC under the following conditions, and the glass transition temperature Tig was determined by JIS K
7121.

(2) Evaluation of Adhesion between Film and Adhesion Modification Layer The adhesion between the syndiotactic polystyrene film and the adhesion modification layer was evaluated by the tape peeling test shown below. A 50mmX60mm size double-sided tape (No.535A manufactured by Nitto Denko Co., Ltd.) was attached to a glass plate, and a syndiotactic polystyrene stretched film with an adhesive modification layer laminated on top of it I pasted it. Next, width 24mm,
100 mm long cellophane tape (CT-24 manufactured by Nichiban Co., Ltd.)
About half of the above is affixed to the surface of the adhesion modification layer, thickness 2 mm, width 30 m
m, 100 mm long polytetrafluoroethylene plate was bent to bend the curved surface of the cellophane tape to make it adhere, and then the cellophane tape was rapidly peeled in the 90 ° direction by hand and the peeled portion was visually observed. Then, when the adhesive layer was not peeled off, and when it was peeled off, the adhesion between the modified adhesive layer and the syndiotactic polystyrene film was evaluated as good or bad.

(2) Evaluation of printability The printability (wettability and adhesion of ink) of the syndiotactic polystyrene film was evaluated according to the following evaluation method. Prepare a test piece of A-4 size (210 mm x 297 mm), and apply gravure ink (NEW Fine R39 indigo manufactured by Toyo Ink Mfg. Co., Ltd.) to the adhesion-modified surface side of the test piece at a thickness of 3 µm, and the temperature is 90 ° C. , Dried for 120 seconds. The test gravure ink used was a commercially available gravure ink diluted with a diluting solvent (NF102, manufactured by Toyo Ink Mfg. Co., Ltd.) and adjusted in viscosity. The viscosity of the gravure ink was measured using a # 3 Zahn cup, and the viscosity was adjusted to 17 seconds. In the above evaluation, the ink having no repellency was evaluated as O, and the ink having repellency was evaluated as X. Further, the adhesion of the ink layer was evaluated by the same peel test as in (1). Those that did not peel off were rated as O, and those that peeled off were rated as X.

Example 1 A water-dispersed copolyester (Vylonal MD-1930 manufactured by Toyobo Co., Ltd.) was used.
A coating solution was prepared by diluting with water: isopropyl alcohol = 9: 1 (weight ratio) so that the solid content concentration was 10%.
As a lubricant, cross-linked polystyrene particles having an average particle size of 2 μm were used as syndiotactic polystyrene (weight average molecular weight 300,00
0) The polymer chips added with 2.0 wt% to 100 wt% and the polymer chips without added lubricant were mixed at a weight ratio of 1: 9, dried and melted at 295 ° C.
Extruded from a T-die with a 00 μm lip gap, adhered to a cooling roll at 40 ° C by an air knife method, solidified by cooling, and
An unstretched film of 0 μm was obtained.

The unstretched film is first rolled by a roll at 110 ° C.
Preheated to 120 ℃, stretched 3.3 times in the machine direction between the rolls with a speed difference, and then with a 150 ℃ ceramic roll.
Perform 12% longitudinal relaxation treatment between metal rolls at 40 ℃, then apply the above coating solution by die coater method, dry with hot air at 70 ℃, preheat the film to 110 ℃ with a tenter, and then crosswise At a stretching temperature of 120 ° C to 3.5 times and at 265 ° C for 10
I fixed it for 2 seconds. Then, 5% lateral relaxation treatment at 230 ℃, 3 between the 220 ℃ ceramic roll and 40 ℃ metal roll.
% Longitudinal relaxation treatment to obtain a biaxially stretched syndiotactic polystyrene film having a thickness of 20 μm. The final coating amount of the coating agent was 0.1 g / m ² . Table 1 shows the evaluation results of the obtained syndiotactic polystyrene film.

[0033]

[Table 1]

Example 2 A syndiotactic product was prepared in the same manner as in Example 1 except that a water-dispersible copolyester (Vylonal MD-1985 manufactured by Toyobo Co., Ltd.) was used as the water-dispersible copolyester. A tic polystyrene film was obtained. The evaluation results of the obtained film are shown in Table 1.

(Comparative Example 1) As a water-dispersible copolyester, a water-dispersible copolyester (Toyobo Co., Ltd.)
A syndiotactic polystyrene film was obtained in the same manner as in the example except that Vylonal MD-1200 manufactured by Virnal was used. The evaluation results of the obtained film are shown in Table 1.
It was shown to.

(Comparative Example 2) Syndiotactic was carried out in the same manner as in Example except that a water-dispersible copolyester (Vylonal MD-1500 manufactured by Toyobo Co., Ltd.) was used as the water-dispersible copolyester. A tic polystyrene film was obtained. The evaluation results of the obtained film are shown in Table 1.

(Comparative Example 3) A syndiotactic polystyrene film was obtained in the same manner as in Example except that the adhesion modifying layer was not applied. The evaluation results of the obtained film are shown in Table 1.

[0038]

As described above, according to the present invention, by adopting the constitution described in the claims, the syndiotactic polystyrene excellent in the adhesiveness between the syndiotactic polystyrene-based film and the adhesion modifying layer is obtained. A polystyrene-based stretched film is provided. Further, it is economical because the adhesion modifying layer can be laminated by the in-line coating method in the film manufacturing process, and it is also excellent in terms of fire risk and working environment because the coating liquid is water-based. Also, the produced film can be recycled.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B29L 9:00 B29L 9:00 (72) Inventor Shinsuke Yamaguchi Toyoda No. 1-1 Katata, Otsu City, Shiga Prefecture Toyobo Achievements In-house Research Institute (72) Inventor Keizo Kawahara 2-1-1 Katata, Otsu City, Shiga Toyobo Co., Ltd. In-house Research Institute F-term (reference) 4F100 AK12 AK12A AK41B AK41C AL01B AL01C BA02 BA03 BA06 BA10B BA10C BA15 CA19 CC00B CC00C DE01 EH46B EH46C EJ37 EJ37A EJ38 GB15 GB41 JA05B JA05C JK06 JL02 JL11 JL16 YY00B YY00C 4F210 AA13A AA21E AB23 AG01 AG03 QC01 QC05 QC06 QD04 QD08 QW05 QW12

Claims (2)

[Claims] 1. An adhesive property composed of a water-dispersible linear copolymerized polyester having a glass transition point of 30 ° C. or lower on at least one surface of a stretched film composed of a styrene-based polymer having a substantially syndiotactic structure. An easily-adhesive syndiotactic polystyrene stretched film in which a modified layer is laminated. 2. An adhesive property-improving layer composed of a water-dispersible copolyester, wherein the water-based coating liquid containing the water-dispersible copolyester is substantially a styrene-based polymer having a syndiotactic structure. The easily-adhesive syndiotactic polystyrene according to claim 1, which is formed by applying it to a stretched film or a uniaxially stretched film, then stretching the film uniaxially or biaxially one or more times, and then heat-treating it. Stretched film.