JP2010155455A - Thermoplastic resin stretched multi-layer film with highly in-plane orientated laminar compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film in which a laminar compound is highly orientated although this idea is conventionally considered not viable, especially, as a film showing excellent mechanical characteristics, barrier properties, heat resistance, dimensional stability, etc. <P>SOLUTION: This thermoplastic resin stretched multi-layer film has a laminated structre consisting of a total of not less than 8 layers and has 0.3 to 15 wt.% of added inorganic matter containing the laminar compound, with a thickness of 3 to 200 μm. In addition, the degree of plane orientation of an inorganic laminar compound to be measured by an X-ray diffraction process, falls within the range of 0.4 to 1.0. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention generally relates to a film made of a resin containing a layered inorganic compound called a nanocomposite. In particular, the present invention relates to a stretched film of a nanocomposite resin that has been conventionally said to be impossible to stretch at a high magnification.

Biaxial stretching of a thermoplastic resin (nanocomposite resin) in which a layered compound typified by layered silicate is uniformly dispersed has traditionally been difficult, but a layer of nanocomposite resin was laminated. By forming and then stretching as a multilayer unstretched sheet, it is possible to stretch biaxially at a high stretch ratio. By making the degree of orientation in the plane of the layered compound at that time 0.4 or more, especially dynamics A film excellent in characteristics, barrier properties, heat resistance, dimensional stability, etc. can be obtained.

  Thermoplastic resins (nanocomposite resins) in which layered compounds such as layered silicates are uniformly dispersed are expected to improve oxygen and water vapor barrier properties and mechanical strength, and are considered for application to films. It has been. However, it becomes difficult to stretch rapidly with the addition amount of the layered compound, and when the amount expected to fully exhibit the characteristics of the addition of the layered compound is added, the layered compound cannot be sufficiently stretched. The planes were not arranged parallel to each other, and the orientation of the layered compound was disordered. For this reason, the properties of the stretched film actually obtained are far from various physical properties that are said to be theoretically obtained.

  In particular, a biaxially stretched polyamide resin film is excellent in mechanical properties, barrier properties, pinhole resistance, transparency, and the like, and is widely used as a packaging material. However, due to the high hygroscopic property derived from the amide bond in the resin skeleton, the mechanical strength changes due to the change in humidity, and hygroscopic elongation occurs, and problems are likely to occur in various processes. In addition, the glass transition point of the resin itself is not so high, and it is desired to improve heat resistance, particularly mechanical properties at high temperatures.

  As a method for improving heat resistance and hygroscopicity of polyamide resin, it is known to uniformly disperse layered silicate, and this method is known as nanocomposite formation. Since various properties described above are improved by nanocompositing, it is expected that a film with improved properties will be obtained by filming, but in reality, these resins are generally poor in stretchability, It is not suitable as a resin for stretched films. In particular, it is said that it is necessary to add 1% or more of a layered silicate to a polyamide resin in order to sufficiently enhance the effect of improving the mechanical properties, but a polyamide resin having such a high layered silicate content. Then, the difficulty of stretching was remarkable.

  Patent Document 1 discloses a biaxially stretched polyamide film containing a layered silicate, but in order to overcome the difficulty of stretching, the maximum temperature reached 180 ° by successive stretching in the width direction next to the length direction. A high temperature of −200 ° C. is essential, and the layered silicate is not sufficiently oriented because the crystal proceeds excessively before sufficient stretching in the width direction is achieved, as well as difficulty in production. In other words, there are problems that the effect of adding various layered silicates does not appear, thickness spots occur in fine regions, and pinhole resistance is not achieved.

  Furthermore, even if such a special method is adopted, as can be seen from the claims, it is practically 1% by weight or less (including the organic component contained between the layers), and beyond that, whitening during stretching, It has been pointed out that the productivity is poor at high stretch ratios. This is considered to be because stress tends to concentrate on the tip of the layered compound during stretching, and glazes and cracks are likely to occur.

Patent Document 2 also discloses a patent for a stretched film in which a layered inorganic compound is added in an amount of 0.5 to 5%, but there is no specific measure for solving the above-described poor stretchability. There is no description, and it is the result of examination at the level where small pieces were simultaneously biaxially stretched in the laboratory, industrial production by sequential biaxial stretching in a system to which a layered compound at a high concentration of 1% or more was added There is no technical disclosure about the stretching method having the property. In addition, there is a description in the text that layered inorganic compounds such as montmorillonite are effective in improving slipperiness by blocking water absorption, but when a material such as montmorillonite is added to nylon resin, the equilibrium water absorption rate of the resin is To increase. From this, it can be said that the essence of the invention largely depends on the effect of addition of the inorganic lubricant.

On the other hand, Nishino et al. Of Kobe University pointed out an interesting result regarding the evaluation of the orientation of the dispersed layered inorganic compound in the stretched film (for example, Non-Patent Document 1). This report pays attention to the 060 reflection in the layer of montmorillonite, and points out that the reflection intensity in the meridian direction increases when the montmorillonite is oriented in the plane.

JP 2003-20349 A JP 2003-313322 A

174th Committee on Molecular Nanotechnology, 1st Seminar (July 13, 2007) Proceedings, p22-23

  The present invention makes it possible to stretch a resin in which a layered compound typified by layered silicate, which has been conventionally difficult to stretch, is uniformly dispersed, under the same stretching conditions as a conventional resin not containing a layered compound. As a result, we provide a film in which layered compounds that were previously considered impossible are oriented in a high dimension, and in particular provide films with excellent mechanical properties, barrier properties, heat resistance, dimensional stability, etc. The task is to do.

  The present inventors consider that a problem in stretching is that cracks are easily generated along the layered compound due to stress in a direction perpendicular to the plane of the layered compound, and the orientation state of the layered compound and reduction of the stretching stress As a result of investigation, in the conventional method, since the molecular chain is fixed by the layered compound, when the cast sheet is stretched vertically, a large stress is applied to the molecular chain in the width and thickness directions. It is considered that the stretching was difficult, so that the shear stress is uniformly applied to the sheet at the time of casting by multilayering to promote the orientation of the layered compound in the in-plane direction, and the crazing generated by the stress concentrated on the tip of the layered compound It was found that the entanglement density in the thickness direction can be lowered by multilayering at the same time that cracking can be suppressed. And paying attention to the in-plane orientation of the layered inorganic compound dispersed in addition to the resin on the matrix side, referring to the report of Nishino et al., Quantitatively grasping the degree of orientation of the layered compound, and examining the relationship of properties, The film obtained by adopting such a method can align the layered compound at a very high level, and the degree of plane orientation obtained from the half width of the X-ray diffraction peak derived from the dispersed layered compound When the value exceeds a specific value, it has been found that it has excellent characteristics not found in the past, and has led to the present invention.

That is, this invention consists of the following structures.
1. An inorganic material containing a layered compound is added in an amount of 0.3 to 15% by weight, has a laminated structure with a total number of layers of 8 or more, and is a thermoplastic resin stretched multilayer film having a thickness of 3 to 200 μm, which is obtained by an X-ray diffraction method. A thermoplastic resin stretched multilayer film, wherein the measured plane orientation degree of the inorganic layered compound is in the range of 0.4 to 1.0.
2. The static mixer method is used when melt-extruding a thermoplastic resin, and the resin temperature immediately before being introduced into the static mixer is in the range of melting point to melting point + 70 ° C., which is higher than the resin temperature immediately before being introduced into the static mixer. 2. The stretched thermoplastic resin multilayer film as set forth in claim 1, wherein the heater temperature in the latter half of the static mixer is increased in the range of 5 ° C. or more and 40 ° C. or less.

  According to the present invention, it has been difficult to obtain good strength and appearance under conventional stretching conditions, and consists of a nanocomposite resin in which a layered compound is uniformly dispersed, various properties, particularly barrier properties, A film having excellent mechanical properties can be provided.

  In addition, about the point that creaking in the thickness direction of the film, which is a problem due to multilayering, is likely to occur, in a multilayer film obtained by the static mixer method, the resin temperature just before being introduced into the static mixer is from melting point to melting point + 70 ° C. It can be improved by raising the heater temperature in the latter half of the static mixer in the range of 5 ° C. or higher and 40 ° C. or lower than the resin temperature just before being introduced into the static mixer.

2 is an X-ray diffraction diagram of Example 1. FIG.

The present invention is described in detail below.
(Thermoplastic resin)
As the thermoplastic resin used in the present invention, a general thermoplastic resin can be used. For example, polyester resin, polyamide resin, polypropylene resin, polyethylene resin, polycarbonate resin, acrylic resin, etc. are exemplified, and those in which other components are copolymerized or blended with other resins can be used. Is not to be done.

  Regarding the polyester resin, in addition to the polyester resin obtained from the aromatic and aliphatic polyfunctional carboxylic acid and the polyfunctional glycol, a hydroxycarboxylic acid-based polyester resin can also be used. Examples of the former include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene adipate, polybutylene adipate, and other copolymers thereof. Examples of the copolymer include polyester resins copolymerized with polyalkylene glycol, polycaprolactone, and the like. Examples of the latter include polylactic acid, polyglycolic acid and polycaprolactone. The former and latter copolymers can also be used.

  The polyamide resin is not particularly limited, such as a ring-opening polymer of cyclic lactam, a condensate of diamine and dicarboxylic acid, and a self-condensation product of amino acids. For example, nylon 6, nylon 7, nylon 66, nylon 11, nylon 12 Nylon 4, Nylon 46, Nylon 69, Nylon 612, metaxylylenediamine-based nylon, and the like, but are not limited thereto. It is also possible to use a copolymerized polyamide resin. Specifically, fragrances such as nylon 6 and nylon 66, nylon 6T, nylon 6I, nylon 6 / 6T copolymer, nylon 6 / 6I copolymer, nylon 6 / MXD6 copolymer copolymerized with metaxylylenediamine A group-based polyamide resin can be used, and those obtained by copolymerizing other components can also be used, but nylon 6, nylon 66, and metaxylylenediamine-based nylon are preferable.

  As the polyolefin resin such as polypropylene resin and polyethylene resin, those obtained by various polymerization catalysts such as Ziegler-Natta catalyst and metallocene catalyst can be used. In addition to these homopolymers, those obtained by copolymerizing other components for the purpose of improving stretchability and impact resistance can also be used. In addition to the above, a cyclic polyolefin resin can also be used.

  Regarding the acrylic resin, various resins obtained by general radical polymerization and ionic polymerization can be used, and are not particularly limited. Regarding the polycarbonate resin, polycarbonate resins having various characteristics can be obtained from various raw materials, but the present invention is not particularly limited.

  Those in which the layered compound is uniformly dispersed in these resins are used in the present invention. In multilayering, the above-mentioned resin not containing a layered compound and a resin having a different amount of layered compound may be used at the same time. Further, in the present invention, a necessary characteristic in common when used for multilayering is that the melt viscosity is 10 to 10,000 Pa · sec at a shear rate of 10 to 100 / sec during extrusion molding. When the melt viscosity is less than 10 Pa · sec, the effect of the arrangement of the layered compounds is thin and undesirable during lamination. If it exceeds 10000 Pa · sec, for example, it is difficult to divide and invert the layer when passing through a static mixer, and in an actual system, it is difficult to form a multilayer.

  Further, other resins and additives may be added to these resins and used, but it is preferable to use them within a range in which deterioration of characteristics is kept to a minimum. In addition, from the viewpoint of economy, it is one of the preferred embodiments that the film produced in this patent is recovered and used again as a part or all of the thermoplastic resin.

(Layered compound)
Examples of the layered compound include layered compounds such as swellable mica, clay, montmorillonite, smectite, hydrotalcite, and bentonite, but are not limited to these and can be used regardless of inorganic or organic.

  The shape of the layered compound is not particularly limited, but the average length of the major axis is 0.01 to 50 μm, preferably 0.03 to 20 μm, particularly preferably 0.05 to 12 μm, and the aspect ratio is 5 to 5000. Preferably, those having 10 to 5000 can be suitably used.

  The amount added to the polyamide resin is preferably 0.3 to 20% by weight. The inorganic layered compound may be added as an organically treated layered compound, and the amount added may not always match the content of inorganic substances (added amount) due to the weight residue described below. In addition, if a method for obtaining from a weight residue as described later is employed, a small amount of an inorganic substance other than the layered inorganic compound may be added in addition, and in the present invention, it is obtained as an added amount of the inorganic substance containing the layered compound. become. The content of the inorganic substance containing the layered compound in the present invention is a value obtained by subtracting ash from the weight residue obtained by a calorimeter (TGA). Specifically, the temperature rises from room temperature to 550 ° C. of the resin containing the layered compound. Obtained weight residue after warming, and then obtained by subtracting the value of resin ash. In the case of Example 1, the inorganic content was 2.6% by subtracting 4.4% weight residue by TGA and 1.8% weight residue from resin. Can be sought. Further, the ratio of the organic treating agent in the layered compound can be obtained separately by TGA and calculated from the numerical value.

  Regarding the aspect ratio of the layered compound, a layered compound having a large aspect ratio is preferable when the purpose of addition is to improve barrier properties, and a layer having a small aspect ratio is preferable when the purpose of addition is mechanical reinforcement.

  The lower limit value of the amount of the inorganic substance containing the layered compound is more preferably 0.3%, further preferably 0.7%, and particularly preferably 1.0%. If it is less than 0.3%, the effect of the addition of the layered compound is small, which is small in terms of dimensional stability and mechanical properties. The upper limit is more preferably 15%, further preferably 12%, and particularly preferably 10%. If it exceeds 15%, the effects in terms of dimensional stability and mechanical properties are saturated, which is not economical, and the fluidity at the time of melting is also lowered.

  Although these layered compounds can be used in general, commercially available organically treated products suitably used in the monomer insertion polymerization method described below include Cloisite from Southern Clay Products, Somasif from Corp Chemical, Lucentite, Examples include Hosoon Sben.

(Thermoplastic resin in which the layered compound is uniformly dispersed)
A thermoplastic resin in which a layered compound is dispersed is generally called a nanocomposite resin. It is preferable that the layered compound is uniformly dispersed and does not include a coarse product having a thickness exceeding 2 μm in an aggregate of the layered compound. Including a coarse product exceeding 2 μm is not preferable because transparency and stretchability are reduced. Illustrating a method for producing a thermoplastic resin in which a layered compound is dispersed,
1. Intercalation method:
1) Monomer insertion polymerization method 2) Polymer insertion method 3) Organic low molecular insertion (organic swelling) kneading method In-situ method: In-situ filler formation method (sol-gel method)
3. The ultra-fine particle direct dispersion method is mentioned as the manufacturing method, and as an example of nanocomposite resin, specifically, nylon-based Nanopolymer Composite Corp. NF3040, NF3020, Ube Industries' NCH 1015C2, MXD nylon-based Nanocor Imperm103, Imperm105, PP-based Polykemi Scancomp, and so on. When dispersing the layered compound in the resin, the layered compound is preferably treated with various organic treatment agents in order to increase the dispersibility of the layered compound in order to suppress the generation of coarse substances, In order to avoid adverse effects due to thermal decomposition of the treating agent at the time, those obtained by using a method such as a monomer insertion polymerization method in which a low molecular weight compound having good thermal stability or a low molecular weight compound is not used are preferable. Regarding thermal stability, a compound having a 5% weight loss temperature of 150 ° C. or higher of the treated layered compound is preferable. TGA etc. can be used for the measurement. Low thermal stability is undesirable because it may cause bubbles in the film or cause coloration (challenge nanotech materials, polymer nanocomposites with widespread use, published by Sumibe Tsutsunaka Techno Co., Ltd.) See).

  These layered compounds are preferably oriented in the plane of the obtained film in order to develop the characteristics. The in-plane orientation can be confirmed by observing the cross section using a transmission electron microscope or a scanning electron microscope.

(Film forming method)
In the stretching of a resin containing a layered inorganic compound in the present invention, the problems in stretching using sequential biaxial stretching, which is generally advantageous in terms of economy, are as follows: (1) Longitudinal direction (hereinafter abbreviated as MD) ), The crystallization proceeds with the heat during stretching, and the stretchability in the transverse direction (hereinafter abbreviated as TD) is lost after uniaxial stretching. (2) Breakage occurs during TD stretching. (3) TD stretching There are three points that breakage occurs when heat-fixed later. For (1), MD stretching conditions that allow TD stretching and MD stretching conditions that do not allow TD stretching are arranged. It was found that there was a difference in the refractive index in the width direction of the stretched sheet (refractive index in the Y-axis direction, hereinafter abbreviated as Ny). Specifically, Ny of a uniaxially stretched sheet that can be TD-stretched is Ny smaller after MD stretching, whereas TD stretching cannot be performed (that is, whitening or breaking occurs during TD stretching) Ny showed little or no change in Ny after MD stretching. In normal polyamide resin stretching, Ny after MD stretching causes necking in the width direction during MD stretching and Ny decreases at the same time, but when layered compounds are added, necking occurs but the layered It was found that Ny tends not to decrease due to the interaction between the compound and the polyamide resin molecule. This is because the molecular chains of the film before stretching are randomly oriented in the MD and TD directions, so when the molecular chains are stretched in the MD direction by MD stretching, force in the TD direction is also generated, but normal polyamide In the stretching of the resin, the force applied in the TD direction can be released by necking in the TD direction. On the other hand, in the case of the polyamide resin containing the layered compound, the molecular chain is constrained by the layered compound. Because the force in the direction cannot be released and the molecular chain is stretched in the TD direction as well, or the layered compound rotates during MD stretching. It was thought that the molecule was pulled in the direction of. That is, the plane orientation is already high after uniaxial stretching. For this reason, it was considered that the stretching stress at the time of subsequent TD stretching was increased and the fracture occurred.

  As a method for solving this, by adopting a stretching condition in which Ny decreases after MD stretching, TD stretching performed subsequently can be stretched at a high magnification without causing breakage, etc. It became possible to manufacture on a scale.

  Ny (A) -Ny (B) is preferably 0.001 or more when the refractive index in the width direction before longitudinal stretching is Ny (A) and the refractive index in the width direction after longitudinal stretching is Ny (B). . Further, it is preferably 0.002 or more, most preferably 0.003 or more.

  As a method of lowering Ny after uniaxial stretching, a method of greatly reducing the MD stretching speed can be applied, but the same effect can be obtained by multilayering the unstretched sheet after melt extrusion. Ny can be reduced by reducing the molecular chain entanglement density in the thickness direction by multilayering, thereby improving the ease of deformation of the molecular chain, and as a result, the plane orientation during MD stretching Can be suppressed and TD stretchability can be improved. It has been found that these methods can improve the biaxial stretchability, and can realize a stretched film that is industrially highly practical and excellent in properties.

(Structure of the film)
Regarding the total number of layers and the thickness of the layers, the lower limit of the number of layers is preferably 8 or more, and more preferably 16 or more. The upper limit of the number of layers is preferably 10000 layers or less, and more preferably 5000 layers or less. Less than 8 layers is not preferable because the effect of improving stretchability is not observed, and the effect of alignment during melt extrusion of the layered compound is reduced, which is not preferable. On the other hand, if it exceeds 10,000 layers, the effect of improving stretchability is saturated, and a decrease in the heat shrinkage rate is observed, which is not preferable.

  Further, the lower limit of the layer thickness is more preferably 10 nm, and even more preferably 100 nm, in the state before stretching. If it is less than 10 nm, the crystal size in the layer becomes too small and the thermal shrinkage rate becomes large, which is not preferable.

  The upper limit of the layer thickness is preferably less than 30 μm, and more preferably less than 20 μm. If it exceeds 30 μm, the in-plane orientation of the layered compound in the state before stretching is low, and the effect for reducing the stretching stress is small, which is not preferable.

(Lamination method)
In the present invention, when the above-mentioned thermoplastic resin is multilayered, it is also possible to laminate a resin composition having the same composition in addition to laminating different types of commonly employed resins. Here, it may be difficult at first glance to find out the physical meaning of multilayering the resin composition of the same composition by the method described later, but in the actual system, the resin composition of the same composition is the same. Even in the case of melt extrusion lamination at a temperature, the interface of the layers does not disappear but exists after stretching. This is synonymous with the fact that it is very difficult to eliminate the weld line of the injection molded product. Thus, even if it is the same kind of resin, a multilayer state is maintained, and it is possible to maintain low molecular entanglement in the thickness direction. As a method of confirming the existence of the interface of layers when melt-extrusion and lamination of the same kind of resin, after cooling the sample with ice or liquid nitrogen, cutting out with a razor or the like, creating a cross section, and then immersing it in a solvent such as acetone It can be observed by a method of observing the cross section with a microscope. The fact that the interface of this layer remains without disappearing means that there is a layer with a different modulus of elasticity, etc., and by using this point, a process of gradually reducing the layer thickness is provided. Stretching and alignment in the direction parallel to the layer interface of the compound occurs, and the desired property improvement is possible. As for the above effects, layered compounds represented by layered silicates are generally present in a pellet in a state of being shrunk or curled in a round shape. It is difficult to stretch the curled state to the most suitable state for stretching in the present invention. It is also an effect that does not appear by simply crushing the pellet. However, it is possible to extend and orient the layered compound to some extent in advance by extruding it as a thin multilayer structure in this way, so that in the subsequent longitudinal stretching step, the molecules are excessive in addition to the longitudinal direction. It is thought that smooth stretching was possible without applying force.

  The thermoplastic resin in the present invention and, if necessary, the resin composition constituting the other layers are supplied to different extruders and extruded at a temperature equal to or higher than the melting temperature, but the melting temperature is 5% higher than the decomposition start temperature. It is preferable that the temperature is lower than ℃

  In addition, when laminating the same kind of resin, it is possible to make a multilayer structure by introducing only one static mixer in the melt line between one extruder and the die, which is the most economical method. One. Also, in order to suppress cracking of the layered compound in the resin, the melting conditions and the melting temperature should be set carefully. For example, in the case of a high molecular weight thermoplastic resin, the melting point is less than + 10 ° C. When melting at a low temperature, the layered compound is cracked, the aspect ratio is smaller than the initial state, and the effect of using the layered compound with a high aspect ratio is reduced, so there is no problem in terms of thermal stability It is preferable to melt at a high temperature.

  The thermoplastic resin in the present invention and the resin composition constituting other layers as required are laminated by various methods, and methods such as a feed block method and a multi-manifold method can be used. In the case of the feed block method, when the width is expanded to the die width after lamination, if there is a large difference in melt viscosity between the layers to be laminated or a temperature difference during lamination, lamination unevenness will occur, resulting in deterioration in appearance and thickness unevenness. Therefore, it is preferable to pay attention during the production. In order to suppress unevenness, etc., the melt viscosity at the time of extrusion is adjusted by (1) lowering the temperature, (2) adding various additives such as polyfunctional epoxy compounds, isocyanate compounds, carbodiimide compounds, etc. Preferably it is done.

  In the present invention, the in-plane orientation of the layered compound is promoted by the shearing force at the time of lamination, whereas the stress concentration at the time of stretching is concentrated at the tip of the layered compound, making it difficult to break. As a suitable method for such a purpose, lamination by a feed block method or a static mixer method is preferable, and a static mixer method is particularly preferable from the viewpoint of simplicity of equipment.

When multi-layering is performed by the static mixer method, the resin temperature immediately before being introduced into the static mixer is in the range of melting point to melting point + 70 ° C, and the latter half of the static mixer is higher than the resin temperature immediately before being introduced into the static mixer. The heater temperature is preferably set high in the range of 5 ° C. or more and 40 ° C. or less. If the melting point is less than the melting point before being introduced into the static mixer, the melt viscosity is too high and the appearance is deteriorated. On the other hand, at a high temperature of melting point + 70 ° C. or higher, the melt viscosity is too low and the force necessary for the effect of stretching the layered compound becomes small, which is not preferable. In addition, the heater temperature in the latter half of the static mixer is preferably set higher than the resin temperature immediately before being introduced into the static mixer, but if the temperature difference is less than 5 ° C, streaky unevenness is observed. It is not preferable because a thin portion that causes a drop or breakage may be formed. If it exceeds 40 ° C., the melt viscosity is too low, and the force necessary for the effect of stretching the above-mentioned layered compound becomes small, which is not preferable. The difference in melting temperature of each layer when the thermoplastic resin is laminated is 70 ° C. or less, preferably 50 ° C. or less, more preferably 30 ° C. or less. In addition, the difference in melt viscosity of the resin between the layers is within 30 times, preferably within 20 times, more preferably within 10 times the estimated shear rate in the die, thereby suppressing the appearance and unevenness during lamination. It becomes possible. In adjusting the melt viscosity, the addition of the aforementioned polyfunctional compound can be used. The static mixer temperature or feed block temperature during lamination is lower than the 5% decomposition temperature of the resin, and the melting point of the resin is preferably +20 to melting point + 150 ° C., more preferably the melting point +30 to Melting point + 120 ° C., most preferably melting point +40 to melting point + 110 ° C. When the feed block temperature is low, the melt viscosity becomes too high and the load on the extruder becomes too large, which is not preferable. When the temperature is high, the viscosity is too low and uneven lamination occurs, which is not preferable. In addition, the film after biaxial stretching may be apt to be hazy due to multilayering. In this case, the temperature of the second half of the static mixer or feed block and the die is sufficiently high, and the molecular chains are entangled between the layers. It can be improved by increasing. Specifically, in the case of a static mixer, the effect of suppressing creaking can be seen by making the heater temperature at the outlet temperature higher than the inlet temperature in the range of 5 to 40 ° C.

  Multi-manifold stacking is also possible, and the above-mentioned problem of uneven stacking is unlikely to occur. However, when laminating layers with different melt viscosities, poor wraparound of each layer resin occurs at the end. In this case, it is preferable to control the difference in melt viscosity.

  The die temperature is the same as described above, but is preferably in the range of 150 to 380 ° C, preferably 170 to 350 ° C, more preferably 180 to 320 ° C. If the temperature is too low, the melt viscosity becomes too high and the surface becomes rough and the appearance deteriorates. An excessively high temperature is not preferable because, besides the thermal decomposition of the resin, the difference in melt viscosity becomes large and unevenness occurs as described above, and particularly unevenness with a small pitch occurs.

  About the thickness of each layer before extending | stretching, it is preferable to make each layer into the range of 0.01-30 micrometers. When the thickness of the resin layer exceeds 30 μm, the effect of improving stretchability is low, which is not preferable for the present invention. If it is less than 0.01 μm, the heat shrinkage rate after heat setting becomes large, and the improvement effect such as barrier property becomes small, and it becomes difficult to balance with various properties, which is not preferable.

(Stretching method)
The thermoplastic resin stretched multilayer film of the present invention can be stretched by sequential biaxial stretching and simultaneous biaxial stretching of an unstretched sheet melt-extruded from a T-die, and other methods such as a tubular method can be used. In order to perform sufficient orientation, a method using a biaxial stretching machine is preferred. A preferable method from the standpoints of characteristics and economy includes a method of stretching in the longitudinal direction with a roll type stretching machine and then stretching in the transverse direction with a tenter type stretching machine (sequential biaxial stretching method). As for MD stretching, as described above, in order to improve TD stretchability, it is preferable to reduce the refractive index (Ny) in the width direction during MD stretching, in order to reduce Ny while increasing the MD stretching ratio. It is preferable to use MD multistage stretching.

  By stretching the unstretched sheet after melt extrusion into multiple layers as described on the left, the stretching conditions such as the temperature and speed during stretching can adopt the usual conditions for stretching a resin that does not contain a layered compound. .

  A substantially unoriented thermoplastic resin sheet obtained by melt extrusion from a T-die is 2.5 to 10 times in the MD direction at a glass transition temperature of the resin of Tg ° C. or higher and a temperature rising crystallization temperature (Tc) + 50 ° C. or lower. Then, the longitudinally stretched film obtained was stretched 3.0 to 10 times at a temperature of 50 ° C. or higher and a melting point (Tm) ° C. or lower, and then the biaxially stretched film was heated in a temperature range of 150 to 300 ° C. It is preferable to obtain it by fixing.

  The temperature rising crystallization temperature can be obtained by heating the rapidly cooled sample after melting the resin by DSC, and the dynamic viscoelasticity change of the uncrystallized sheet-like sample during the temperature rising process is tracked It can also be confirmed.

  In MD stretching, when the film temperature is lower than the glass transition temperature Tg ° C. of the resin, problems such as breakage due to orientation crystallization due to stretching and thickness unevenness occur. On the other hand, when the temperature of the film exceeds the temperature rise crystallization temperature (Tc) + 50 ° C. of the resin, breakage occurs due to crystallization by heat, which is inappropriate. Further, if the draw ratio in MD stretching is less than 1.1 times, problems such as poor quality such as thickness unevenness and insufficient strength in the longitudinal direction occur, and if it exceeds 10 times, subsequent TD stretching becomes difficult. A preferable draw ratio is 3.0 to 8.0 times.

Furthermore, when the temperature of the film in TD stretching is a low temperature of less than 50 ° C., the TD stretchability is poor and breakage occurs, and the thickness variation in the TD direction due to neck stretching increases, which is not preferable. When the temperature is higher than (Tm) ° C., thickness spots increase, which is not preferable. In addition, when the TD stretch ratio is less than 1.1 times, the thickness variation in the TD direction is unfavorably increased, and in addition to the point where the strength in the TD direction is lowered, the in-plane orientation of the layered compound is lowered, and the object is achieved. The effect for improving the properties is reduced, which is not preferable, and a draw ratio of 3 times or more is preferable. Further, when the TD stretch ratio is higher than 10 times, it is substantially difficult to stretch. Particularly preferred TD stretch ratio is 3.0 to 9.0.
Is double.

  For example, in the case of polyethylene terephthalate, the stretching temperature is preferably in the range of 80 to 130 ° C., and in the case of nylon 6 resin, the MD stretching temperature is 50 to 100 ° C., TD stretching. In the case of a polypropylene resin, the temperature is 60 to 150 ° C, and the MD stretching temperature is 50 to 100 ° C and the TD stretching temperature is 150 to 200 ° C. In order to fully demonstrate the effect of layered silicate addition, it should be adjusted for the purpose. For example, in the case of nylon-based nanocomposite resin, when emphasis is placed on gelboflex resistance, etc. The stretching temperature is suitable for stretching at a low temperature, and specifically, it is suitable to perform TD stretching in the range of 100 to 150 ° C.

  In the present invention, the unstretched sheet is preferably stretched at least in the range of 6 to 50 times in terms of area. When the draw ratio is less than 6, the in-plane alignment of the inorganic layered compound is insufficient, and the effect of improving the characteristics is small. If it exceeds 50 times, the stretchability of the resin itself is insufficient, which is industrially disadvantageous, which is not preferable. A more preferable draw ratio is 8 times or more, and further 9 times or more. The upper limit is preferably 45 times, and further 40 times. The upper limit varies depending on the resin, but the limit is approximately equal to the stretch ratio of the resin film to which no layered compound is added.

  The film thickness after stretching is preferably in the range of 3 to 200 μm. If it is less than 3 μm, the handling of the film is unfavorable. On the other hand, if it exceeds 200 μm, the effect of inorganic composite becomes small, which is not preferable.

  In the present invention, both ends in the width direction of the unstretched sheet multi-layered by the static mixer method or the feed block method are cut off by using a method such as cutting as necessary, and at the outermost end before stretching. It is preferable to perform stretching in at least one direction after the thickness of each laminated layer is at least 30 μm or less. In the above multi-layering method, depending on the structure of the die, the number of end layers may be reduced due to imperfect division of layers during layering or disorder of the layers. Becomes larger than 30 μm, the stretchability of only the end portion is greatly reduced, and phenomena such as whitening and breakage of the end portion may be observed during stretching. In the present invention, in this case, for the purpose of correcting the layer thickness of the end portion to the desired thickness at the time of manufacture, trimming the end portion of the unstretched sheet and then stretching is one of preferred manufacturing methods. It is.

(Heat fixing)
For example, in the case of a polyamide resin, if the heat setting temperature is a low temperature of less than 150 ° C., the heat setting effect due to the heat of the film is small and inappropriate. On the other hand, a high temperature exceeding 250 ° C. is inappropriate because it causes poor appearance due to whitening caused by thermal crystallization of polyamide and a decrease in mechanical strength. In the case of a polyester resin, the range of 180 to 250 ° C. is preferable for the above reason. Other resins should be determined in consideration of the thermal characteristics of the resin. Specifically, in the case of polyethylene terephthalate, the range of 200 to 250 ° C can be exemplified, and in the case of polypropylene, the range of 150 to 200 ° C can be exemplified.

  In heat setting after TD stretching, density increase due to crystallization and accompanying volume shrinkage occur. However, in the case of a resin containing a layered compound, the generated stress is very large. Will break. For this reason, as a heating method at the time of heat setting, it is preferable to increase the amount of heat in a stepwise manner to suppress the generation of a rapid contraction stress. As a specific method, there are methods such as gradually increasing the temperature or increasing the air volume from the vicinity of the entrance of the heat setting zone to the vicinity of the exit, and gradually reducing the air volume in terms of the heat shrinkage rate after stretching and heat setting. The heat setting method which raises is preferable.

  Regarding the relaxation treatment, it is preferable to determine the relaxation rate in consideration of the balance with the thermal contraction rate in the vertical direction. In the present invention, since the longitudinal dimension change in moisture absorption is small, the relaxation rate is preferably in the range of 0 to 5%. If it exceeds 5%, the effect for reducing the thermal shrinkage in the width direction is small, which is not preferable.

  Industrially, the film thus obtained is used for various applications as it is or in the form of a roll film wound around a paper tube or the like after undergoing processing such as printing or laminating. The roll film is preferably 30 cm or more in width. The length is preferably 500 m or more. The upper limit of the width is usually about 600 cm, and the upper limit of the length is about 20000 m. A wide film or a long film immediately after film formation is slit according to the application, and is usually used as a roll film having a width of 200 cm or less and a length of 8000 m or less.

(Surface orientation of thermoplastic resin)
The plane orientation (ΔP) after biaxial stretching, heat setting, and relaxation treatment of the thermoplastic resin film in the present invention varies depending on the thermoplastic resin used, but in the case of a polyamide resin, it is 0.03 or more, preferably 0.05 or more. Is preferred. When birefringence is obtained from a refractometer, the refractive index in the longitudinal direction is Nx, the refractive index in the width direction is Ny, and the refractive index in the thickness direction is Nz.

ΔP = (Nx + Ny) / 2-Nz

In the case of polyethylene terephthalate, ΔP is 0.10 or more, but the plane orientation can be increased by increasing the biaxial stretching ratio, especially the TD stretching ratio. The strength is lowered, which is not preferable.

(Film characteristics-plane orientation of inorganic layered compounds)
The film in the present invention improves the heat resistance, barrier properties, dimensional stability, and mechanical properties by highly orienting the layered compound in the plane, but the thermoplastic multilayer film in the present invention is an X-ray diffraction film. The degree of plane orientation of the inorganic layered compound measured by the method is preferably in the range of 0.4 to 1.0. Here, the degree of plane orientation is from the half width of the (0n0) peak of the layered compound.

Plane orientation = (180-half width) / 180

It is a numerical value calculated by. If the degree of plane orientation is less than 0.4, the plane orientation is low and the effect of adding an inorganic layered compound is reduced, which is not preferable.

  In order to increase the degree of plane orientation of the layered compound, stretching of 6 times or more is preferable in terms of area, and a stretching ratio of 3 times or more is more preferable in the lateral direction. If it is less than 6 times in terms of area, the arrangement of the layered compounds is insufficient, and the effect of improving the characteristics is small. If it exceeds 50 times in terms of area, the difficulty in production exceeds the effect, which is not preferable in terms of productivity.

  The multilayer stretched film in which the layered compounds in the present invention are arranged in the plane is excellent in heat resistance and mechanical properties.For heat resistance, for example, in dynamic viscoelasticity, the temperature at which the storage elastic modulus starts decreasing near Tg is high. It may be possible to move to the side. This is due to the reinforcing effect that the layered compound suppresses the movement of the molecular chain of the thermoplastic resin, and the effect is small if the arrangement of the layered compound is insufficient.

The multilayer stretched film in which the layered compounds in the present invention are arranged in the plane is excellent in barrier properties. For example, for improvement of oxygen barrier properties to polyamide resins, the amount of inorganic substance containing layered compounds to the polyamide resin is added. When 0.3 to 15% is added, the oxygen permeability (20 to 25 cc / m ² / day / atm) of biaxially stretched polyamide resin in terms of 15 μm is up to about 5 to 15 cc / m ² / day / atm. Can be reduced. If it is less than 1%, the effect of improving the barrier property is small, and if it exceeds 10% by weight, the effect of improving the barrier property is saturated and it is not economical. Similar effects can be confirmed for polyester resins and polypropylene resins in addition to polyamide resins.

(Film characteristics-haze)
The haze of the thermoplastic resin film in the present invention is preferably in the range of 1.0 to 20%. If the haze at the time of stretching is less than 1.0%, it is difficult to produce stably, which is not preferable. If the haze exceeds 20%, it is not preferable because the design properties are deteriorated in addition to making it difficult to see the contents during use.

  The haze in the present invention is the sum derived from the resin, the layered inorganic compound, and the void derived from the peeling of the resin during stretching on the surface of the layered inorganic compound, but it is particularly preferable to reduce the haze derived from the void. The conditions are preferably set carefully. Specifically, when the MD temperature is too low, the haze increases due to the formation of voids, which is not preferable. Also, when the TD temperature is too high, haze increases due to crystallization, which is not preferable. The preferred temperature range is as described above, but can be adjusted with reference to this. Furthermore, it can adjust with the magnitude | size and kind of layered compound. For example, it is possible not only to reduce the haze by using a layered compound that is smaller than the wavelength of visible light, but also to employ a layered compound having a refractive index close to that of the resin. Can reduce the haze.

(Film characteristics-surface roughness, coefficient of static friction)
In the thermoplastic resin film of the present invention, a powdery lubricant can be added in accordance with the application and the like to adjust the surface roughness and slipperiness. When added, the average particle size of the lubricant particles is preferably 0.1 to 10 μm, more preferably 0.3 to 5 μm. The particle diameter can be measured by an electron microscope and the average value can be obtained. The addition amount is preferably 1000 ppm or less, and more preferably 700 ppm or less.

  An average particle size of less than 0.1 μm is not preferable because it is too small for the purpose of changing the surface roughness. When particles having an average particle diameter exceeding 10 μm are used or when the amount added exceeds 1000 ppm, the effect is saturated and it is not economical. Various particles such as silica, alumina, zirconia, titania, crosslinked acrylic beads, crosslinked styrene beads, and benzoguanamine can be used as the particles.

(Film characteristics-pinhole resistance)
The stretched multilayer film in the present invention is excellent in pinhole resistance. For example, in the case of nylon 6 resin, the number of pinholes after 1000 gelboflex tests at 23 ° C. is preferably 0 to 30. . The reason why the pinhole resistance is not lowered by the addition of the inorganic layered compound is considered to be due to the in-plane arrangement of the inorganic layered compound and stretching at a high magnification. It is mainly the stretching conditions that have an influence on the resistance to pinholes, and among them, it is preferable that the temperature during TD stretching is not particularly high. If the TD stretchability is poor, the temperature may be raised, but if the stretching temperature is raised too much above the low temperature crystallization temperature, crystallization proceeds partially without sufficient stretching, resulting in a thickness in a fine region. Unevenness and pinholes are likely to occur. Also, pinholes are likely to occur in the obtained film.

  The thermoplastic resin stretched multilayer film of the present invention may be subjected to corona treatment, coating treatment or flame treatment in order to improve adhesion and wettability depending on the application. In the coating process, an in-line coating method in which a film coated during film formation is stretched is one preferred embodiment. The thermoplastic resin stretched multilayer film of the present invention is generally further subjected to processing such as printing, vapor deposition, and lamination depending on the application.

  The thermoplastic resin stretched multilayer film of the present invention has a hydrolysis resistance improver, antioxidant, colorant (pigment, dye), antistatic agent, conductive agent, flame retardant, reinforcing agent, filler, inorganic lubricant, organic lubricant , A nucleating agent, a release agent, a plasticizer, an adhesion assistant, a pressure-sensitive adhesive, and the like can be optionally contained.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not restrict | limited at all to these examples, unless the summary is exceeded. The measurement method used in the present invention is shown below.

(1) Addition amount of inorganic substance including layered compound (weight residue)
Using TA Instruments TGA, the weight residue was obtained after heating up to a sample amount of 0.1 g, a nitrogen stream and a temperature increase rate of 20 ° C./min to 500 ° C.

(2) Haze
The sample was measured at three different locations using a haze meter (Nippon Denshoku, NDH2000) by the method according to JISK7105, and the average value was defined as haze.

(3) Plane orientation degree of layered compound The degree of plane orientation of montmorillonite was measured for a film obtained by stretching a resin in which montmorillonite was dispersed in nylon 6 resin. In the case other than montmorillonite, it can be obtained by the same method. RINT2500 Cu-Kα manufactured by Rigaku Corporation was used as the apparatus, and the half-value width of the montmorillonite (060) peak obtained by the X-ray diffraction method at an output of 40 kV and 200 mA was determined. From half width,

Degree of plane orientation of inorganic layered compound = (180-half width) / 180

I asked more. Here, in order to obtain the half width of the montmorillonite (060) peak, measurement was performed by the following method. (1) An X-ray is incident on the film sample from the width (TD) direction. (2) Fix the sample at the position of θ = 31.4 ° and the detector at 2θ = 62.8 ° with respect to the incident X-ray. (3) The sample stage is rotated in-plane (β rotation) from 0 to 360 °, and the X-ray diffraction intensity is measured. (4) From the obtained X-ray diffraction intensity plot (FIG. 1), a portion excluding ± 60 ° around the peak top is linearly approximated by the least square method to obtain a baseline. (5) The peak width at the half height from the baseline to the peak top obtained in (4) is defined as the half width.

(4) Observation of orientation state of layered compound in film A sample was prepared by the following method and observed using a transmission electron microscope. First, the sample film was embedded in an epoxy resin. As the epoxy resin, a mixture of Luavec 812, Luavec NMA (manufactured by Nacalai Tesque) and DMP30 (TAAB) in a weight ratio of 100: 89: 3 was used. After embedding the sample film in an epoxy resin, the sample film was left in an oven adjusted to a temperature of 60 ° C. for 16 hours to cure the epoxy resin and obtain an embedded block.

  The obtained embedding block was attached to an ultra cut N manufactured by Nissan Sangyo, and an ultrathin section was prepared. First, trimming was performed using a glass knife until a cross section of a portion desired to be observed for the film appeared on the resin surface. Next, an ultrathin section was cut out using a diamond knife (Sumitomo Electric, Sumiknife SK2045). After cutting out the ultrathin section on the mesh, carbon deposition was performed thinly. The electron microscope observation was carried out using JEM-2010 manufactured by JEOL under the condition of an acceleration voltage of 200 kV. An image obtained by electron microscopic photography of the film cross-section was recorded on an imaging plate (FDLUR-V, manufactured by Fuji Photo Film). From the images, 50 layered compounds were randomly extracted and the inclination of each was evaluated. When the variation in tilt of any layered compound falls within an angle of 20 degrees or less, it is assumed that the layers are oriented in the plane. In-plane orientation was marked with ◯, and non-oriented orientation was marked with x.

(5) Scratch resistance The biaxially stretched film was cut out with a cutter, cellotape (registered trademark) was attached to the end face, and left at room temperature for 24 hours. Thereafter, the tape was peeled off at an angle of 90 degrees to check for the presence or absence of kaikai.

(6) Glass transition temperature (Tg) measurement and low-temperature crystallization temperature (Tc) measurement An unoriented resin sheet is frozen in liquid nitrogen, and after thawing under reduced pressure, a DSC manufactured by Seiko Electronics Co., Ltd. is used at a heating rate of 20 ° C./min. It was measured.

(7) Mechanical properties (elastic modulus)
Conforms to JIS K 7113. A sample having a width of 10 mm and a length of 100 mm in the longitudinal direction and the width direction of the film was cut out using a razor as a sample. After being left for 12 hours in an atmosphere of 23 ° C and 35% RH, the measurement was performed in an atmosphere of 23 ° C and 35% RH under the conditions of a distance between chucks of 40 mm and a pulling speed of 200 mm / min. Values were used. As a measuring device, an autograph AG5000A manufactured by Shimadzu Corporation was used. The high temperature MD elastic modulus was measured in an oven heated to a predetermined temperature under conditions of a distance between chucks of 40 mm and a pulling speed of 200 mm / min, and an average value of five measurement results was used.

(8) Dynamic Viscoelastic Property Test Measurement was performed with a dynamic viscoelasticity measuring apparatus manufactured by IT Measurement Co., Ltd., and the measurement length was 30 mm, the displacement was 0.25%, the frequency was 10 Hz, and the measurement environment temperature was 23 ° C. The sample was cut into a length of 40 mm and a width of 5 mm in parallel with the film width direction, and an average value of two values was used. Further, tan δ was calculated by the following equation.

tan δ = imaginary part of complex elastic modulus / real part of complex elastic modulus

(9) Layer thickness and total number of layers in the film The film was cooled with liquid nitrogen and taken out immediately, and cut out in the width direction of the cast film or stretched film with a feather blade to obtain a cross section. This cross section was observed using an optical microscope (Olympus BX60), and a value obtained by dividing the thickness of the layer for 5 to 20 layers by the number of layers was determined as the layer thickness. The total number of layers was determined by the same method. When it was difficult to understand the interface of the layer by the above method, a sample was prepared by the following method and observed using a transmission electron microscope. First, the sample film was embedded in an epoxy resin. As the epoxy resin, a mixture of Luavec 812, Luavec NMA (manufactured by Nacalai Tesque) and DMP30 (TAAB) in a weight ratio of 100: 89: 3 was used. After embedding the sample film in an epoxy resin, the sample film was left in an oven adjusted to a temperature of 60 ° C. for 16 hours to cure the epoxy resin and obtain an embedded block. The obtained embedding block was attached to an ultra cut N manufactured by Nissan Sangyo, and an ultrathin section was prepared. First, trimming was performed using a glass knife until a cross section of a portion desired to be observed for the film appeared on the resin surface. Next, an ultrathin section was cut out using a diamond knife (Sumitomo Electric, Sumiknife SK2045). After cutting out the ultrathin section on the mesh, carbon deposition was performed thinly.
The electron microscope observation was carried out under the condition of an acceleration voltage of 200 kV using JEM-2010 manufactured by JEOL. An image obtained by electron microscopic photography of the film cross-section was recorded on an imaging plate (FDLUR-V, manufactured by Fuji Photo Film). From the image, the thickness of the layer having the maximum thickness was measured from the distance between the interfaces of each layer.

(10) Oxygen transmission rate (OTR)
An oxygen permeability measuring device (“OX-TRAN 10 / 50A” manufactured by Modern Controls) was used, and measurement was performed at a humidity of 65% and a temperature of 23 ° C. The obtained result was converted to a value at a thickness of 15 μm as oxygen permeability (OTR, cc / m ² / day / atm). Conversion to the value at 15μm thickness is

(15 μm thickness equivalent OTR) = (actually measured OTR) × (film thickness, μm) / 15 (μm)

As sought.

(Comparative Example 1)
Nylon 6 resin pellets in which montmorillonite is uniformly dispersed as a layered compound (NF3040 from Nanopolymer Composite Corp., layered compound addition amount: 4% (inorganic content 2.6%) are vacuum-dried at 100 ° C overnight, then two units The same resin is supplied to the extruder, melted at 280 ° C, laminated using a 16-element static mixer heated to 280 ° C, and then heated to 275 ° C in a sheet form on a cooling roll adjusted to 20 ° C. A multilayer unstretched sheet was produced by extruding and cooling and solidifying.The ratio of the discharge amount of the two extruders was 1: 1, and the thickness of the unstretched sheet was 150 μm, and the thickness of each layer was about The sheet had a number of layers of 100 or more, and the Tg of this sheet was 35 ° C. and the melting point was 225 ° C. The sheet was first preheated at a temperature of 40 ° C., and then stretched at a temperature of 60 ° C. Longitudinal stretching is performed at a deformation rate of 2300% / min. This sheet is continuously led to a tenter, stretched twice at a preheating temperature of 60 ° C and a stretching temperature of 70 ° C, heat-fixed at 210 ° C and subjected to 5% lateral relaxation treatment, cooled, and width An unstretched portion in the direction was cut and removed to obtain a biaxially stretched polyamide resin film having a thickness of 30 μm, and the film had a width of 40 cm and a length of 1000 m, and was wound on a paper tube. Is shown in Table 2.

Example 1
An unstretched sheet was obtained in the same manner as in Comparative Example 1. Next, the sheet was preheated with a roll with a surface temperature of 45 ° C, and stretched 3.2 times with a roll with a surface temperature of 80 ° C at a deformation rate of 4500% / min, and this sheet was continuously guided to a tenter and preheated. Biaxially stretched polyamide resin with a thickness of 12μm, stretched 3.8 times at a temperature of 110 ° C and a stretching temperature of 135 ° C, heat-fixed at 210 ° C and subjected to 5% lateral relaxation treatment, cooled, and trimmed to remove the edges. A film was obtained. The film had a width of 40 cm and a length of 1000 m and was wound around a paper tube. Table 1 shows the film physical properties at this time. The plane orientation of the layered compound was improved from 0.2 in Comparative Example 1 to 0.82, and the value of OTR in terms of 15 μm was greatly reduced from 17 cc to 12 cc.

(Example 2)
Nylon 6 resin pellets in which montmorillonite is uniformly dispersed as a layered compound (NF3040 manufactured by Nanopolymer Composite Corp., layered compound addition amount: 4% (inorganic content 2.6%) are vacuum-dried at 100 ° C overnight, and then the pellet is extruded. The melt temperature is adjusted to 270 ° C. in the melt line, and a 16-element static mixer in which the molten resin is heated to the inlet portion 270 ° C./center to the outlet portion 285 ° C. is introduced. A multi-layer unstretched sheet was produced by extruding a laminate of the same kind of resin from a T-die heated to 280 ° C. into a cooling roll adjusted to 20 ° C. and cooling and solidifying the unstretched sheet. The thickness of each layer in the central part in the width direction was about 1 μm, and the Tg of this sheet was 40 ° C. The sheet was first preheated at a temperature of 45 ° C. and then stretched at a stretching temperature of 80 ° C. Step stretching was performed. MD stretching at 1950% / min is doubled and the second stage MD stretching is also performed at 1950% / min at double, and this sheet is continuously led to a tenter, with a residual heat zone of 110 ° C and a stretching zone of 130 ° C. The film was TD-stretched 4 times, heat-fixed at 210 to 215 ° C. and subjected to 5% transverse relaxation treatment and then cooled, and both edges were cut and removed to obtain a biaxially stretched polyamide resin film having a thickness of 15 μm. The film had a width of 40 cm and a length of 1000 m and was wound on a paper tube.The obtained film was excellent in puncture resistance, and the film physical properties at this time are shown in Table 1. The surface of the layered compound The degree of orientation was improved from 0.2 in Comparative Example 1 to 0.89, and the OTR value in terms of 15 μm was greatly reduced from 17 cc to 10 cc.

(Examples 3 to 5)
Samples were prepared under the conditions described in Table 1. Table 1 shows the film characteristics and the like. In addition, the OTR value in terms of 15 μm was improved to around 12 cc with the improvement of the plane orientation degree of the layered compound.

(Comparative Example 2)
Nylon 6 resin pellets (NF3040 made by Nanopolymer Composite Corp., layered compound addition amount: 4% (inorganic content 2.6%)) in which the layered compound is uniformly dispersed were vacuum-dried overnight at 100 ° C. Next, a single layer Films were formed using an inflation film forming machine, and the pellets were supplied to an extruder and melted at 290 ° C. Next, the pellets were extruded from an annular die heated to 280 ° C., and air-cooled while discharging amount, winding speed, tube diameter The biaxially stretched polyamide resin film having a thickness of 20 μm was obtained by cutting the central portion of the tube, and the physical properties of the film are shown in Table 2.
(Comparative Example 3)
Polyethylene terephthalate resin pellets (RE553, manufactured by Toyobo Co., Ltd., montmorillonite powder (Cloisite10A, manufactured by Southern Clay Products) as a layered compound were each vacuum dried at 100 ° C overnight, and then dry blended at a weight ratio of 85/15 Then, it was put into a twin screw extruder and melted and mixed at 295 ° C. The obtained resin pellets were again dried in a vacuum dryer at 100 ° C. for 24 hours. By melting at 295 ° C, laminating the same type of resin using a 16-element static mixer at 285 ° C, extruding from a T-die heated to 285 ° C in a sheet form on a cooling roll adjusted to 20 ° C, and solidifying by cooling A multi-layer unstretched sheet was prepared, the thickness of the unstretched sheet was 100 μm, and the thickness of each layer in the central portion in the width direction was about 1 μm, and the Tg of this sheet was 65 ° C. Preheating treatment at temperature Next, MD stretching was performed twice at a deformation rate of 2500% / min with a roll having a surface temperature of 110 ° C, and this sheet was continuously guided to a tenter. The film was TD-stretched twice, heat-fixed at 230 ° C. and subjected to 5% transverse relaxation treatment, cooled, and both edges were cut and removed to obtain a 25 μm-thick biaxially stretched polyethylene terephthalate resin film. The film had a width of 40 cm and a length of 1000 m, and was wound up on a paper tube.

(Example 6)
A biaxially stretched polyethylene terephthalate resin film was obtained in the same manner as in Comparative Example 3, except that the thickness of the sheet before stretching was 400 μm, the MD stretch ratio was 4 times, and the TD stretch ratio was 4 times. The film had a width of 40 cm and a length of 1000 m and was wound around a paper tube. Table 1 shows the film physical properties at this time. As compared with Comparative Example 3, the storage elastic modulus at 100 ° C. in the dynamic viscoelasticity of the obtained film increased approximately 20 times from 50 MPa to 50 MPa, resulting in an increase in heat resistance. Had improved.

(Comparative Example 4)
Polypropylene resin pellets (Noblen FS2011, manufactured by Sumitomo Chemical Co., Ltd.) and organically treated montmorillonite powder (Cloisite30B, manufactured by Southern Clay Products) as a layered compound were dry blended at a weight ratio of 80/20, and then charged into a twin screw extruder. Melted and mixed at 0 ° C. The obtained resin pellets were dried in a vacuum dryer at 100 ° C. for 24 hours. This resin was supplied to an extruder, melted at 275 ° C, the same kind of resin was laminated using a 275 ° C 16-element static mixer, and heated to 275 ° C in a sheet form on a cooling roll adjusted to 20 ° C. A multilayer unstretched sheet was produced by extruding from a die and cooling and solidifying. The thickness of the unstretched sheet was 150 μm, and the thickness of each layer in the center in the width direction was about 1 μm. This sheet is first pre-heated at a temperature of 50 ° C., then MD stretched twice at a deformation rate of 3000% / min with a roll having a surface temperature of 130 ° C., and this sheet is continuously led to a tenter to maintain the remaining heat. TD-stretched twice at a zone of 160 ° C and a stretch zone of 165 ° C, heat-fixed at 155 ° C and subjected to 5% lateral relaxation treatment, then cooled, and both edges were cut and removed, with a biaxial thickness of 25 µm A stretched polypropylene resin film was obtained. The film had a width of 40 cm and a length of 1000 m and was wound around a paper tube. Table 2 shows the film physical properties at this time.

(Example 7)
In Comparative Example 4, a biaxially stretched propylene resin film was obtained in the same manner except that the thickness of the sheet before stretching was 1000 μm, the MD stretch ratio was 6 times, and the TD stretch ratio was 8 times. The film had a width of 40 cm and a length of 1000 m and was wound around a paper tube. Table 1 shows the film physical properties at this time. The degree of planar orientation is sufficiently high, and for example, it is expected that gas barrier properties, heat resistance, etc. will be improved.

(Example 8)
MXD6 polyamide resin pellets (Nanocor Imperm 105, layered compound addition amount: 7%) in which montmorillonite was uniformly dispersed as a layered compound were vacuum-dried at 100 ° C. overnight, and then the pellets were supplied to an extruder. A 16-element static mixer that was melted at 280 ° C and heated to 280 ° C in the melt line, and the same type of resin was laminated to a cooling roll adjusted to 20 ° C from a T die heated to 270 ° C. A multi-layer unstretched sheet was produced by extruding into a shape and cooling and solidifying. The thickness of the unstretched sheet was 200 μm, and the thickness of each layer in the center in the width direction was about 1 μm. This sheet is first pre-heated at a temperature of 80 ° C., then stretched at a temperature of 100 ° C., a deformation rate of 5000% / min, and a magnification of 3.5 times. Biaxially stretched polyamide resin film with a thickness of 15μm, TD-stretched 3.5 times at 95 ° C in the stretching zone, heat-fixed at 180 ° C and 3% transverse relaxation treatment, cooled, and cut and removed both edges. Got. The film had a width of 40 cm and a length of 1000 m and was wound around a paper tube. Table 1 shows the film physical properties at this time.

  The stretched thermoplastic resin multilayer film of the present invention is obtained by adding a layered compound, and the effect of improving various properties is maximized by highly orienting the layered compound in the plane. It is intended for this purpose, is excellent in appearance, has high productivity, and has high industrial utility value. In addition, since the resulting film is excellent in barrier properties, dimensional changes and mechanical properties, it can be used for applications that have been difficult to use in the past. In addition to packaging materials such as foods, pharmaceuticals, and miscellaneous goods, It can also be suitably used as an industrial material.

Claims (2)

  An inorganic material containing a layered compound is added in an amount of 0.3 to 15% by weight, has a laminated structure with a total number of layers of 8 or more, and is a thermoplastic resin stretched multilayer film having a thickness of 3 to 200 μm, which is obtained by X-ray diffraction. A thermoplastic resin stretched multilayer film, wherein the measured plane orientation degree of the inorganic layered compound is in the range of 0.4 to 1.0.   The static mixer method is used when melt-extruding a thermoplastic resin, and the resin temperature immediately before being introduced into the static mixer is in the range of melting point to melting point + 70 ° C., which is higher than the resin temperature immediately before being introduced into the static mixer. The stretched thermoplastic resin multilayer film according to claim 1, wherein the heater temperature in the latter half of the static mixer is increased in the range of 5 ° C to 40 ° C.

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