JPH0367547B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application) The present invention relates to a technology for improving polyamide resins, and relates to improving mixed resin compositions in the field of melt extrusion processing, in which the properties of polyamide resins are modified by mixing with other types of resins. (Prior Art) Conventionally, polyamide resins have the advantages of the resin itself, that is, they have a high level of toughness, heat resistance, cold resistance, oil resistance, surface smoothness, etc. Because it has the advantage of having a certain level of gas barrier properties, it is used in the technical field of melt extrusion molded products, either as a single resin or as a resin for layer construction of laminates. . Specifically, for example, molten resin is extruded into a predetermined mold and molded into the shape of the mold, and molded into toys such as plastic models and dolls, their parts, gears, packing, shafts, etc.
Injection molding processing for making mechanical parts such as bearings, carpentry parts such as door wheels, joints, curtain sliders, odor-proof sealed containers, household containers such as saucers, etc.
Alternatively, continuous molding of pipes, rods, wire coatings, etc., where the cross-sectional shape of the extruded product is maintained, extrusion blow molding, extrusion blow molding, etc., where an extruded cylindrical body is inflated to form a container of a predetermined shape, etc. It is used in many melt extrusion molding methods, such as casting molding in which a plate-shaped body is cooled and then taken off, and many molded products thereof are also known. Furthermore, when polyamide resin is given appropriate orientation, its mechanical properties are further enhanced and heat shrinkage properties can be added. Also widely known is an extrusion stretch-molding method in which a stretched film is formed by stretching or inflation-type stretching. However, one of the drawbacks of this polyamide-based resin is that the change in melt viscosity is highly temperature dependent, and in the low viscosity region, the inherently large drawdown phenomenon increases, so it cannot be processed by melt extrusion. Extrusion processing, which requires uniformity, requires a large amount of energy and advanced technology. That is, for example, when extruding resin, adopting extrusion conditions that prevent large drawdowns increases the specific energy during extrusion, but it is still not possible to prevent large drawdowns, and it is necessary to attach the material to a casting roll directly under the die, or to use a mandrel. Problems are being dealt with by making full use of advanced techniques such as insertion, and seeking a balance between the resulting increase in thickness unevenness and other negative effects.Furthermore, for example, stretching of high viscosity resin, especially in order to give a high degree of orientation. Stretching requires a large amount of stress, and this high stress becomes an obstacle. For example, in inflation stretching, if the parison has uneven thickness, the uneven thickness increases due to stress concentration near the yield point. , the increase in internal pressure within the bubble limits the scope of application of inflation stretching, and limits the quality level of the resulting product and the manufacturing equipment that can be used.
The problem is that the degree of freedom of means is reduced. The second drawback of polyamide resins is that when they are classified as gas barrier resins, their gas barrier properties are unsatisfactory. Moreover, the level of gas barrier properties is significantly lowered by the hygroscopicity of the resin. Furthermore, a third drawback, related to the above-mentioned hygroscopicity, is that changes in mechanical strength and dimensional stability are highly dependent on humidity. The second and third drawbacks mentioned above are noticeable in blow molded products and stretch (film) molded products that have a large ratio of surface area to unit weight of resin. Therefore, especially in the field of packaging films, which are used under various environmental conditions and require high gas barrier properties, polyamide resins are rarely used as single-layer films, and are used as moisture-proof surfaces. On the other hand, since a layer is applied, it can be said that there is a disadvantage in that the excellent properties of polyamide resin cannot be utilized as they are. Hereinafter, in this specification, descriptions in the field of films, particularly evaluations of properties, etc., are often made in the case of single-layer stretched films. This idea is aimed at developing a polyamide resin composition that can overcome the three disadvantages of polyamide resins, particularly in the field of films where the adverse effects of hygroscopicity are significant, especially in the field of stretched films. If this can be obtained, it is believed that this composition can naturally be used in the field of lamination and thick-walled injection, where the influence of hygroscopicity is small. The difference from the prior art that is closest to the content of the present invention is that first, a mixed resin composition of polyamide resin and other resins is made, and the above-mentioned drawbacks of polyamide resin are solved by making use of the properties of that composition. The technical idea of this is publicly known. Among them, those with technical ideas closest to the present invention include:
For example, (i) Japanese Patent Application Laid-Open No. 146758, (ii) Japanese Patent Application Laid-Open No. 1983-146758,
Publication No. 16576, (iii) Japanese Unexamined Patent Publication No. 167751, and
(iv) There is a technique described in Japanese Patent Publication No. 56-33425. However, these prior art techniques cannot reach the content of the present invention in terms of their effects, that is, the content of the drawbacks to be solved and the level of quality thereof. This will be explained in detail in the latter half of the specification. Here, it is made clear that the technical concept of the structure of the present invention is not an extension of the above-mentioned prior art. First, prior art (i) shows that olefinic ionomer resin can be mixed with polyamide resin.
In (ii), the saponified ethylene vinyl acetate copolymer can be mixed with the polyamide resin, and in (iii), the polyamide resin can be mixed with both the polypropylene resin and the olefinic ionomer resin.
Each is described. Each of these teaches some improvement over the drawbacks of polyamide resins. Therefore, taking the above (i), (ii), and (iii) together, although there are appropriate component ranges, at least three of them are polyamide resin, saponified ethylene vinyl acetate copolymer, and olefinic ionomer resin.
It can also be said that it teaches that the seed resins are compatible with each other and can be mixed without special consideration. Furthermore, regarding (iv) above, it specifically teaches that the three resins themselves can be used to form a mixed resin composition, although the purpose is slightly different. However, if we explain in detail the content described in (iv) above, in reality, the component range in which these three types of resin can be mixed with transparency (same quality as HAZE) is that the polyamide resin component is 25 to 40% by weight ethylene. It clearly states that the content of the saponified vinyl acetate copolymer component is 20 to 65% by weight, and the content of the olefinic ionomer resin component is 10 to 40% by weight. In other words, the document (iv) indirectly teaches that the range of mixed resin components referred to in the present invention is a range of components that are considered to be impractical due to decreased transparency. . Table 1 below and attached Figures 6, 7, and 8 are as follows:
This is an example of a phenomenon that served as a stepping stone for the completion of the present invention.
HAZE of the resulting extrudate (parison)
This is a table of experimental results (see Example 1 for details). First of all, what Table 1 means is that even in the same mixed resin component range, depending on the kneading ability of the extruder (the state of the resin being mixed), there are areas where the HAZE remains bad and unchanged, and areas where the HAZE is high ( The region where the HAZE changes from the bad) state to the low (good) state is distributed in a narrow region, indicating that the region where the HAZE changes depending on the kneading ability exists exactly in the region of the resin component referred to in the present invention.

【table】

[Table] The relationship between Figures 6, 7 and 8 is a diagram of a cross-sectional state of a parison, which shows an example of the phenomenon analysis that provided one foothold for the completion of the present invention. show. Also, in this case, Figure 6 corresponds to the experiment in Table 1.
The parisons in cases No. 1~, and Figures 7 and 8 correspond to the parisons in cases No. 1~ and 3~, respectively, are treated by immersing the cross section of each parison in DMSO (dimethyl sulfoxide). This is a typical example of the cross-sectional state when First, the relationship between Figures 6 and 7 is that both parisons appear to be cloudy to the same degree, and there is no difference in appearance, but the resin solvent (DMSO in this case) When I tried processing, DMSO
This indicates that the state of the distribution of the resin portion (in this case, estimated to be both the saponified ethylene vinyl acetate copolymer and the olefinic ionomer resin) dissolved in the mixture (the state of the mixture may appear different when analyzed) In other words, in Fig. 6, the distribution of the resin part dissolved by DMSO is detected as a scattering of rather large particles, whereas in Fig. 7,
It appears to be detected as a distribution that resembles an arrangement of many filaments. In the case of the one in Figure 6, as shown in Table 1-3, the cloudy state of the parison does not change even if the kneading level of the extruder changes, and the cross section of the parison is not much different from that in Figure 6. On the other hand, in the case of the one in Figure 7, the transparency of the parison was significantly improved as shown in Table 1-3, and the dispersion state of the resin in the cross section of the parison was as shown in Figure 8. This shows that the state changes to a dispersed state of scattered small particles. In other words, the relationships shown in Figures 6 to 8 show that even in areas where it is evaluated that there is no difference in the mixing state of the resins based on the appearance of the parison, there is a difference in the mixing state based on the distribution of the component resins. There are areas where there are differences, and the areas of the resin composition of the present invention were discovered for the first time by the present inventor, who has continued to thoroughly investigate the state of distribution of individual component resins using various solvents. This shows that this is an untapped area of success. Therefore, the various properties exhibited by the resin composition of the present invention can be said to be previously unknown properties in which the dispersion and distribution state of the component resins is improved. It should be noted that the quality of the kneading ability of the extruder referred to here depends on, for example, the shape and structure of the extruder kneading section and its specifications, etc., and it is difficult to express it quantitatively.In the end, it depends on the distribution of the resin components of the mixed and extruded product. I have to look at it and decide. However, when using a resin composition in the area of the present invention, it is necessary to evaluate whether the HAZA value of a flat parison with a wall thickness of about 0.4 mm extruded from the die slit can be 5% or less.
It can be used as an index of the mixed state. (Problems to be Solved by the Invention) The present invention solves the drawbacks of conventionally known polyamide resins, namely, large drawdown during melt extrusion processing, and the specific energy required for extrusion and stretching under extrusion processing conditions. The problem is that the stress is large,
If you try to improve this by mixing it with other resins, you will not be able to maintain the same level of gas barrier properties, transparency, low-temperature toughness, thermal expansion and contraction properties, mechanical properties under wet conditions, etc. All at the same time. The objective is to improve the quality to a level that satisfies practical use. Therefore, the first objective is to determine the specific energy during extrusion under drawdown control conditions and the stress required during stretching (stretching stress) when subjected to melt extrusion processing. A polyamide-based mixed resin with excellent transparency and low-temperature toughness that significantly reduces both of these factors, and yet achieves a level of gas barrier properties (O ₂ TR) that has not previously been achieved for polyamide-based resins. The second objective is to provide a composition which, when made into a melt extrusion molded product, especially a stretched film which is susceptible to the adverse effects of environmental humidity, has a high level of gas barrier properties and a high level of mechanical properties. To provide a film with less adverse effects of humidity (humidity dependence) and/or to provide a film with high heat shrinkability and heat shrinkage stress while maintaining a high level of room temperature dimensional stability and low temperature toughness. The goal is to Furthermore, the third objective is to improve the size of drawdown, which is a major obstacle especially during film molding, to a small one as a resin composition, in relation to the first and second objectives above. In other aspects, such as inserting a mandrel into an extruded parison, for example, there are equipment measures that can adversely affect product quality such as film surface condition and thickness unevenness, or the condition setting and operation aspects. To make it possible to economically produce a wide film having a target width without using any. (Means for Solving the Problems) The object of the present invention is to provide a mixed resin composition containing polyamide resin as a main component with other resins, in which the polyamide resin is 80 to 60% by weight based on the total amount of resin. %, saponified ethylene vinyl acetate copolymer is 10~
30% by weight, α-olefin ionomer resin [or α-olefin ionomer resin is the main component, other components are ethylene-acrylic acid copolymer resin, modified ethylene-vinyl acetate copolymer resin, ethylene-vinyl acetate 2 or more resins that are one or more resins selected from copolymer resins] are 10 to
This can be easily achieved by preparing a polyamide-based mixed resin composition characterized by being mixed at a component ratio of 30% by weight (however, a total of 100% by weight), and then subjecting it to melt extrusion and molding. can be achieved. (Function) Hereinafter, the characteristic contents of the present invention will be explained in detail using drawings and the like. Figure 2 shows the ease of melt extrusion of resin compositions.
In the experimental diagram showing an example (see Example 2 for details), the vertical axis is the specific energy during extrusion [unit: KW-hr/
Kg], and the horizontal axis is the screw rotation speed (unit: rpm) during extrusion. The one of the two curves I is representative of the resin composition according to the present invention,
This is the case of a single polyamide resin shown for comparison. According to the results shown in Figure 2, the resin composition of the present invention reduces the specific energy during extrusion by about 30% under steady conditions (around 70 to 80 RPM) compared to the case of polyamide resin alone. It shows. This reduction in the specific energy value itself during extrusion can also be achieved, for example, by increasing the extrusion resin temperature and lowering the extrusion viscosity. However, in the case of polyamide resin, lowering the viscosity of the extruded resin will result in further increasing the normally large drawdown phenomenon, so the extrusion resin temperature should be set low from the perspective of controlling this drawdown. is normal. In the case of the second experiment, the drawdown size of both resins (extrusion diameter - diameter of extrudate under the set distance), which was evaluated just to be sure, was
35 mm, and 17 mm on the composition side of the present invention, it can be seen that the extrusion conditions at a resin temperature of 240°C used for comparison are extrusion conditions that take into account the control of drawdown, which is generally said. . Furthermore, experiments were also conducted to solve the problem that must be solved when applied to film production, namely, the problem of solving the above-mentioned drawdown phenomenon that inevitably occurs during extrusion using known cooling means. According to the results, in the case of the composition of the present invention, the drawdown of 17 mm could be reduced to 0 mm using the simple method of water film cooling, whereas in the case of polyamide resin, mandrel cooling, which required sophisticated techniques, was achieved. It was absolutely necessary to adopt a law. This difference is presumed to be based on essential differences in the resin compositions of the present invention, such as a small drawdown value and a small temperature dependence of viscosity change. FIG. 3 is an experimental diagram showing an example of the ease of stretching, especially the ease of stretching, of a resin composition melt extrudate (see Example 2 for details), and the vertical axis is the stretching stress [unit: Kg/ mm ² ] The horizontal axis is the stretching temperature [° C.], and is a diagram showing the case of 3 times stretching. One of the two lines is a representative of the resin composition of the present invention, and the other is the case of a polyamide resin alone as a comparative product. The meaning shown in FIG. 3 is that the resin composition of the present invention can be stretched with a stretching stress that is about 2/5 lower than that of polyamide resin. That is, when manufacturing a stretched film using, for example, an inflation stretching method, it is generally considered that it is extremely difficult to stretch a resin that has a large stretching stress. The reason for this is that the higher the stretching stress the resin requires, the higher the internal pressure of the gas in the inflation bubble used for stretching is required. This increase in internal pressure makes it extremely difficult to inject gas into the bubbles, and makes it extremely difficult to inject gas into the bubbles. This is because the occurrence of bubble punctures may increase, or the stretched film may have amplified thickness unevenness. Furthermore, the negative impact on environmental health caused by the popping sound produced when a high internal pressure inflation bubble is blown is also a major obstacle. Under these circumstances, the composition of the present invention shown in FIG. 3 reduces the stress value necessary for stretching polyamide resin, which is said to be difficult to stretch, to a low value of about 2/5. It is significant in that it shows the fact that stretching has become easy. FIG. 4 is an experimental diagram showing an example of the unique properties of the resin composition of the present invention (see Example 3 and Comparative Example 3 for details).
). That is, the horizontal axis shows the tension heat setting treatment temperature conditions during film production, and the left vertical axis shows the shrinkage rate of the obtained film in hot water at 90°C [unit;
%], the right vertical axis is the dimensional change rate [unit: %] of the obtained film at room temperature, the solid line is when the resin composition of the present invention is used, and the broken line is when the polyamide resin alone is used. shows the relationship between The meaning of FIG. 4 is that, in general, the hot water shrinkability and room temperature dimensional change of a film are controlled by the tension heat setting treatment conditions. However, since the values for both of them behave in the same manner depending on the set processing conditions, the degree of freedom in adjusting them is small.For example, the hot water shrinkage rate is large, but the room temperature dimensional change rate is also large (the room temperature dimensional stability is poor). ) Although it is easy to make a film, it is impossible to make a film that has a large shrinkage rate in hot water but a small dimensional change rate at room temperature. On the other hand, in the field of tension packaging that utilizes the heat-shrinkability of film, a film with a high heat-shrinkage value of at least 26% is required in order to make tighter packaging. In order to ensure stability, the dimensional change rate at room temperature is required to be 2% or less. Therefore, in the case of the polyamide resin alone (broken line), it is in a limit state where it is difficult to satisfy the above requirements, whereas in the case of the resin composition of the present invention (solid line), it is difficult to meet the above requirements. This means that it has a sufficient margin in the dimensional change rate (a state of excellent dimensional stability) and can meet the demand for increasing the hot water shrinkage rate.

【table】

[Table] Table 5 above is a table of comparative experiment results (detailed examples/comparison (See Example 3). According to the results in Table 5, the characteristics of the resin composition of the present invention when compared with polyamide resins are that it exhibits low values for both O ₂ TR and WVTR (good barrier performance); Moreover, it has been demonstrated that the barrier performance is sufficiently maintained even under high humidity conditions. Furthermore, in terms of mechanical strength, such as tensile strength, although it cannot be said that the value under standard conditions is superior to that of polyamide resin alone, under high humidity conditions it may be affected by the adverse effects of moisture absorption. It should be noted that the results far exceed those of the polyamide resin alone because it is less sensitive to heat.

[Table] Table 6 and Figure 5 are experimental results showing a part of the usefulness of the resin composition of the present invention. , shows a comparison with the same type of heat-shrinkable packaging film that is currently commercially available (see Examples - Comparative Example 4 for details).
Therefore, it should be noted that many commercially available films are multilayer films. According to the results shown in FIG. 5, it can be seen that the film made with the composition of the present invention, although it is a single layer, has performance that is at least as good as that of a multilayer commercially available film. This means that the resin composition of the present invention is compatible with conventional polyamide resins, that is, when used as a film in the field of heat-shrinkable and tight packaging that is exposed to various environments.
This breakthrough shows that the conventional wisdom that resins must be laminated with other resins to compensate for their shortcomings has been made, and that even single-layer films can now be adequately addressed. In particular, Figure 5 is an experimental diagram that focuses on and evaluates the temperature behavior of heat shrinkability in Table 6. The horizontal axis shows the hot water temperature when heat shrinking [unit: °C], and the vertical axis shows teeth,
It represents the film shrinkage rate [unit: % (vertical and horizontal average value)] shown at that time. According to the results shown in FIG. 5, the film of the resin composition of the present invention exhibits a high heat shrinkage rate over a wide temperature range, and has the characteristic of exhibiting high heat shrinkage especially under low temperature conditions. I understand. Therefore, the film of the resin composition of the present invention exhibits great effects and is useful when used in fields where low-temperature shrinkability is required, for example, in the field of tight packaging for raw meat foods, processed meat foods, etc. The results shown in Table 6 and FIG. 5 are merely illustrative of the advantages of the composition of the present invention, which can be used even in a single layer, and do not negate its application to multilayers. This means, for example, that when a resin layer as one component of a laminated film exhibits high heat shrinkability as shown in Figure 5, even if the heat shrinkage of the resin layer as a component of another layer is insufficient It can also be easily inferred that this will be supplemented. Next, FIG. 1 is an analysis diagram, which corresponds to the experimental results table in Table 2, and also corresponds to the main part of the claims of the present invention (for details, see Example/Comparative Example 1). That is, Table 2 shows experiments in which various three-component mixed compositions of saponified polyamide resin/ethylene-vinyl acetate copolymer and α-olefin ionomer resin were comprehensively evaluated from the viewpoint of the degree of sufficiency of the object of the present invention described above. This is the result table. However, no regularity can be found from the results in Table 2, and there is only a mixture of good and bad evaluation results. Figure 1 is a triangular diagram showing the component composition (total 100% by weight) of a three-component resin.
Olefin ionomer resin is 100% by weight, and the lower right corner is saponified ethylene vinyl acetate copolymer.
100% by weight. Therefore, the left hypotenuse of the equilateral triangle represents the relationship between the polyamide resin and the α-olefin ionomer resin, and the base represents the relationship between the polyamide resin and the α-olefin ionomer resin.
The relationship between α-olefin ionomer resin and saponified ethylene-vinyl acetate copolymer, and the relationship between the saponified ethylene-vinyl acetate copolymer and polyamide resin on the right-hand oblique side, are scaled so that the proportions of each component are the same. This is a diagram showing the coordinates where the sum of the three components is 100% by weight. This diagram has a second
The content of FIG. 1 is that the results of the comprehensive evaluation shown in the table are plotted at the component coordinate positions of the resin compositions showing the results. According to the analysis results shown in FIG.
- At least point A (80, 10, 10), point B (60, 30,
10) and C point (60, 10, 30), which is surrounded by a triangle formed by a straight line, is required. In other words, the resin composition of the present invention that satisfies the object of the present invention is as follows: polyamide resin component amount = polyamide resin component amount / total amount of the above three component resins x 100 = 60 to 80% by weight α-olefin ionomer component amount = Amount of α-olefin ionomer component/total amount of the above three component resins × 100 = 10 to 30% by weight Amount of saponified ethylene vinyl acetate copolymer component =
It shows that the amount of saponified ethylene vinyl acetate copolymer component/total amount of the above three component resins x 100 = 10 to 30% by weight. Furthermore, from the viewpoint of making the obtained film have properties such as oxygen gas barrier property, hot water shrinkage rate, and transparency to a higher level, it is necessary to use the same coordinate points as point D (70, 15, 15),
Component resin in the range surrounded by the triangle connecting point E (65, 20, 15) and point F (65, 15, 20), that is, polyamide resin component amount of 65 to 70% by weight, α-olefin ionomer 15 to 25% by weight of resin component,
Ethylene vinyl acetate copolymer saponified component amount: 15
It has been shown that it is preferable to choose component resins in the range of ~25% by weight.

[Table] Table 3 is an example showing the results of basic experiments corresponding to other main parts of the claims of the present invention (see Example/Comparative Example 2 for details). Specifically, this Table 3 is α in Figure 1 above.
- Regarding the proposition of what other types of resins can be substituted for the olefinic ionomer resin part,
The answer is given as to what kind of resin should be used in order to satisfy the purpose of the present invention. That is, as for the contents of Table 3, there are three types of resins as candidates for other types of resin: ethylene acrylic acid copolymer resin, modified ethylene vinyl acetate copolymer resin, and ethylene vinyl acetate copolymer resin, or these. Mixed resins such as However, even in the case of this selected resin,
If they are used alone, they will not have the performance to replace ionomer resins, but they must be used in combination with other resins in a hybrid resin component whose main component is α-olefin ionomer resin. This shows that it can be used as a component resin in the resin composition of the present invention in a proportion of 10 to 30% by weight, equivalent to the α-olefin ionomer resin. The reason for this is that, as shown in Figure 1, the composition of the present invention contains specific component regions of three types of resins: polyamide resin, saponified ethylene vinyl acetate copolymer, and α-olefin ionomer resin. This is because it was completed based on the basic concept of mixing, and there are restrictions on changing it to combinations with other resins or changing to multiple types of component resins, and there are sufficient This is thought to be because there is no degree of freedom left in combination. Also, according to the results in Table 3, it is desirable that the amount of the main ionomer resin component of the resin component that can replace the α-olefin ionomer resin be 70%.
Other resin components (i.e., one type of ethylene-acrylic acid copolymer resin, modified ethylene-vinyl acetate copolymer resin, ethylene-vinyl acetate copolymer resin) occupying more than % by weight in the entire resin composition of the present invention or these mixed resin components] is 8% by weight
This indicates that it is desirable to adjust to the following value range. Table 3 does not specifically show the effects of other resin components themselves, but according to the research of the present inventors, when added in small amounts within the range that satisfies the purpose of the present invention, It has been confirmed that it is convenient to apply it to improve the processability and properties of resin compositions (adjustment of crystallization rate, degree of crystallinity, flow viscosity, and improvement of film toughness).

【table】

[Table] Table 7 is a comparison table in terms of effects between the resin compositions described in prior documents (i) to (iv) that are closest to the structure of the present invention described above and the resin composition of the present invention. (See Example/Comparative Example 5 for details). Furthermore, in this table, for each typical resin composition, the magnitude of the improvement effect relative to the polyamide resin alone is shown. According to the results in Table 7, when evaluating the resin composition of the present invention from the viewpoint that all of the disadvantages of polyamide resins are more highly improved, the composition of the present invention It can be seen that the improvement effect is far superior to that of other resin compositions described in literature, and its balanced characteristics do not allow other compositions to follow suit. As detailed above, the component area of the resin composition of the present invention is based on the knowledge that incorrect evaluations are made due to the mixed state of the resin composition, and the enthusiasm and observation means to observe the state. Considering that this is a component area that has already been abandoned in prior literature, and which would be overlooked as an impractical area if not prepared in advance, the above effects of the present invention can be seen from the perspective of new technology. It is attracting attention as an unknown effect that has been successfully redeveloped.

【table】

[Table] The polyamide resin in the present invention is a linear synthetic polymer compound having an acid amide bond -CONH-, and may be a homopolyamide, a copolyamide, or a blend thereof. Specifically, homopolyamides include polycaproamide (nylon-6), polyundecaneamide (nylon-11), polylaurinlactam (nylon-12), and the like. Copolyamides include caprolactam/laurin lactam copolymer (nylon 6/12), caprolactam/hexamethylene diammonium adipate copolymer (nylon 6/66), and laurin lactam/hexamethylene diammonium adipate copolymer (nylon 12). /66)
etc. can be mentioned. These polyamides are
From the viewpoint of suppressing discoloration of the mixed resin or improving the mechanical properties of the stretched film, use homopolyamide or copolyamide with a melting point of 190 to 240°C measured by DSC (differential scanning calorimeter). be able to. The α-olefin ionomer resin in the present invention refers to an ionic copolymer obtained by crosslinking metal ions to a copolymer of α-olefin and an α,β unsaturated carboxylic acid derivative. Here, α-olefins include ethylene, propylene, etc., and α,β unsaturated carboxylic acid derivatives include acrylic acid, methacrylic acid, itaconic acid,
Examples include methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate. Also, as a metal ion, the valence is 1.
-Divalent ones, such as Na ⁺ , Mg ⁺⁺ , Zn ⁺⁺ and the like. The saponified ethylene vinyl acetate copolymer in the present invention has an ethylene content of 28 to 45 mol%,
Those with a saponification degree of 98% or higher can be used. The ethylene-acrylic acid copolymer resin in the present invention refers to a copolymer resin in which carboxyl groups (-COOH) are randomly arranged in a methylene chain, which is produced by a copolymerization reaction of ethylene and acrylic acid. Also, acrylic acid content up to 12% can be used. The modified ethylene-vinyl acetate copolymer resin in the present invention is a chemically modified ethylene-vinyl acetic acid obtained by graft polymerizing an acid anhydride to an ethylene-vinyl acetate copolymer resin having a vinyl acetate content of 5 to 30% by weight. Refers to vinyl copolymer resin. As the acid anhydride, an anhydride of an unsaturated carboxylic acid typified by maleic anhydride is used. As the ethylene-vinyl acetate copolymer resin in the present invention, one having a vinyl acetate content of 10 to 40% by weight can be used. Note that the evaluation items in this specification were evaluated using the following evaluation method and scale. Melting point: DSC (Differential Scanning Calorimeter), Model DSC
Measured using Type-1B (manufactured by Perkin-Elmer). The melting point measurement by DSC is carried out in the heating furnace.
A standard sample that does not absorb or heat heat within the measurement temperature range is placed in one of the sample tray holders, and a measurement sample is placed in the other, and the heating furnace temperature is increased at a rate of 10°C/min to determine the melting curve of the sample. Measured by reading the peak point temperature. Oxygen permeability: ASTMD3985, 23℃, 90%RH
Measured using OXTRAN100 model (manufactured by MOCON).

[Table] The humidity dependence of oxygen permeability is measured under the above conditions at a humidity of 12%RH, and is calculated as follows: (Oxygen permeability at 90%RH) - (Oxygen permeability at 12%RH) )
It is expressed as the oxygen permeability value at /12%RH. Water vapor permeability: ASTM-F-372, 38℃, 90
%RH using an IRD-2 type infrared automatic moisture permeability measurement device (manufactured by MOCON). Unit μ・g/
^m2・24hr, 38℃, 90%RH Reduction rate of tensile strength under high humidity conditions: 90%
RH, sample left at 23℃ for 24 hours and 12%RH,
The tensile strength at break of the sample was measured after being left at 23℃ for 24 hours, and was calculated as follows: (Tensile strength at 12%RH) - (Tensile strength at 90%RH)/12
It is expressed as the tensile strength value in %RH. The above tensile strength was measured in accordance with the method described in ASTM D-638.

[Table] Dimensional change rate at room temperature: 44 in an environment of 40℃ and 90%RH
The shrinkage rate upon aging was measured and expressed as the average value in the vertical and horizontal directions. When this value is small, it is said that the dimensional stability at room temperature is good.

[Table] Hot water shrinkage rate: The shrinkage rate was measured after being immersed in hot water at 90°C for 5 minutes, and expressed as the average value in the vertical and horizontal directions.

[Table] Hot water shrinkage stress: Both ends of a sample with a length of 120 mm and a width of 5 mm were fixed and the stress generated when immersed in hot water at 90°C was measured and defined as the hot water shrinkage stress.

[Table] Low-temperature pinhole resistance: Measurement of the number of pinholes using a Gelbo Flex Tester. A film sample (20 x 28 cm) was mounted in a cylindrical shape, and the film was repeatedly twisted and opened at an angle of 360° without tension, causing bending fatigue.
Measure the number of energized pinholes after going back and forth several times. temperature 5
℃.

[Table] Cloudiness: ASTM1003. At 23℃, 50%RH Integrating sphere type light transmittance measuring device (manufactured by Nippon Seimitsu Kogaku)
Measured using

[Table] Drawdown: 40mmφ as extruder, L/D
= 35, extruded from a hollow die with a diameter of 80 mm and a slit width of 1.0 mm at a screw rotation of 50 rpm under the optimum extrusion temperature conditions for each resin composition, and a take-up speed of 10
When picking up the hollow parison at m/min, the
The diameter of the hollow parison at the 25 mm position was measured with a fixed caliper, and the difference between the diameter of the hollow die and the measured value was determined as the size of the drawdown. That is, the larger the numerical value, the larger the drawdown. Hereinafter, the content of the present invention will be explained in more detail based on experimental examples, examples, and comparative examples. Experimental example 1 Polyamide resin [Toray, Amiran CM-1041
(Product name) manufactured by Toray Industries, Inc.], α-olefin ionomer resin (Himilan #1652 (Product name) manufactured by Mitsui Polychemical Co., Ltd.), saponified ethylene vinyl acetate copolymer [Soarnol E (Product name) Japan Synthetic Chemical Co., Ltd.
Using three types of resin, the resin blending ratio is as follows:
Two types of mixed resin compositions of 70; 25; 5 [category (composition outside the scope of the present invention)] and 70; 15; , the experiments shown in Table 1 regarding the two types of resins
The material was supplied to an extruder equipped with three types of screws shown in Nos. 1, 2, and 3, and was melt-extruded and rapidly cooled to produce six types of extruded parisons with a wall thickness of 0.4 mm. The HAZE of the six types of extruded parisons obtained was evaluated by the method described in the text, and the results are shown in Table 1 in correspondence. Further, from each of the extruded parisons corresponding to Experiment Nos. 1-, 1-, and 3- in Table 1, a thin cross-sectional thin piece was cut and taken out, and the thin piece was soaked in dimethyl sulfoxide (DMSO) solution for 20 minutes. After soaking at ℃ for 24 hours, washing with water and drying, the cross section of the thin piece was observed with an electron microscope set at 300x magnification. These observed images are shown in FIGS. 6, 7, and 8, respectively. According to the results in Table 1, the comparative composition (category) was a cloudy parison (HAZE value of 7 or more) regardless of the level of kneading capacity of the extruder, whereas the composition of the present invention (category) ) becomes cloudy depending on the level of kneading capacity of the extruder (HAZE value 7 or more)
It changes from solid to transparent (HAZE value 5 or less). The cause of this phenomenon will be explained with reference to Figures 6 to 8. In the case of the comparative composition (classification), as shown in Figure 6, the portion of the resin component dissolved in DMSO (in this case, the ethylene The distribution of saponified vinyl acetate copolymer and α-olefin ionomer resin (presumed to be both saponified vinyl acetate copolymer and α-olefin ionomer resin) appears to be dispersed as rather large particles, and furthermore, this dispersion state does not change significantly depending on the level of kneading (see Figure On the other hand, in the case of the composition (classification) of the present invention, as shown in Figures 7 and 8, the resin dispersion initially appeared to be distributed in striae and became cloudy; Depending on the level of kneading, the material changes to a transparent material with a fine grain distribution. The significance of this series of experiments is that the component range of the three-component resin of the present invention, which is generally considered to have good compatibility based on conventional literature results, is represented in Figures 6 and 7, respectively. When there are regions with component compositions with such a distribution state in close proximity, and the two cannot be distinguished visually, if the distribution state of the resin is changed in that component region, the composition changes to a transparent composition. It is extremely difficult to predict that there will be a component region that does. In other words, the field of the resin composition of the present invention can only be discovered with the technical idea of finding and improving slight differences in the distribution of resins that appear to be the same at first glance. This is a region in which this region has been formed, and the characteristics in that region that indicate a composition with improved resin distribution indicate a prediction that can be said to be a previously unknown characteristic. Experimental Example 2 Using the same three types of resins as in Experimental Example 1, a composition of the present invention with a resin blending ratio of 80:10:10 was created in order, and using the extruder shown in Experiment No. 3 in Table 1, Adjust the extrusion resin temperature to 240℃, and adjust the screw rotation speed to 50, 60, 70, 80, 90 [unit: rpm].
An extrusion test was conducted for each level, and the specific energy during extrusion [unit, KW-hr/
Kg]' was calculated, and the results are shown as a curve in Figure 2. For comparison, evaluation calculations were made in the same manner as above for the case of a single polyamide resin, and the results are also shown in FIG. 2 as a curve. According to the results shown in Figure 2, under steady conditions of the extruder (screw rotation, around 70-80 rpm),
The composition of the present invention shows that the specific energy during extrusion can be reduced by about 30% compared to the case of polyamide resin alone. This reduction in the specific energy value during extrusion can be achieved, for example, by increasing the extrusion resin temperature and lowering the extrusion viscosity. However, in the case of polyamide resins, lowering the viscosity of the extruded resin increases the normally large drawdown phenomenon, so the current situation is that the extrusion resin temperature is determined from the viewpoint of controlling this drawdown. Therefore, as a precaution, we evaluated the drawdown size of both resins (die diameter - extrudate diameter under the set distance) using the evaluation method described in the text, and found that the polyamide resin , 35 mm, whereas the composition of the present invention showed a value of 17 mm. These two values demonstrate that the extrusion experimental conditions of Figure 2 were extrusion conditions that took into account drawdown control. On the other hand, from the extruded unstretched sheets of both the resin composition of the present invention and the polyamide resin single product, the width
Cut out many strip-shaped specimens of 10 mm, length 100 mm, and wall thickness 360 μ, and test them at 80℃, 90℃, 100℃, 110℃, 120℃.
Free width uniaxial stretching was carried out at a strain rate of 10,000%/min and a strain amount of 200% (3 times stretching) in a constant temperature bath controlled at five levels of temperature (℃), and each stretching stress (unit: Kg/mm ² ) The results were divided into a third line, with the line representing the composition of the present invention and the line representing the polyamide resin.
Described in the figure. According to the results shown in FIG. 3, the composition of the present invention has about 2/5 of the polyamide resin under each stretching temperature.
It can be seen that it can be stretched with a low stretching stress. This advantage not only increases the degree of freedom in the field of stretching (inflation field of thick-walled, small-diameter seamless tubes), which has been practically abandoned due to the high stress of stretching, but also It is attracting attention as a major breakthrough in the stretching of polyamide resins, which previously required a high level of technical skill to prevent stretching unevenness. Furthermore, we investigated ways to improve the drawdown that inevitably occurs during extrusion by using post-processing methods. That is, the aim is to minimize the phenomenon of reduction in the diameter of the cylindrical parison extruded from the circular die by using the cooling means and conditions that are applied to the parison directly below the die. According to the experimental results, in the case of the composition of the present invention,
For the extruded cylindrical parison, approximately
By adopting a cooling method (water film water cooling method) that forms a water film on the surface of the parison of 20 mm or more, it does not adversely affect the uneven thickness of the resulting film or the surface properties.
Furthermore, it was found that a film could be produced by reducing the drawdown phenomenon of 17 mm to a value of 0 mm. On the other hand, in the case of polyamide resin, for example, in the water film water cooling method described above, the parison near the die surface sways, making it impossible to form a stable film, and in the end, a metal cooling mandrel with adjusted surface smoothness is used. Unless a cooling means was employed to bring the inner surface of the cylindrical parison into close contact with the surface, it was not possible to reduce the 35 mm drawdown phenomenon to a value of 0 mm. The mandrel of this mandrel cooling method is inserted into the inside of the cylindrical parison and suspended and fixed directly below the die, and the cylindrical parison, which flows at a constant speed while still in a flowing state, flows over the surface of the mandrel. It is brought into contact with the inner surface of the entire circumference, and this contact acts as a resistance to the reduction of the diameter of the parison, which is cooled and solidified, thereby stabilizing the running of the parison itself as a whole. Therefore, for example, if the contact resistance is even slightly too large, the running state of the flow section will be disturbed, and if the contact is insufficient, cooling spots will occur and the running state will be disturbed. Furthermore, if the cooling start point or cooling rate changes, phenomena such as changes in contact resistance are likely to occur, so a high level of technical ability is required in terms of product design, material selection, and processing accuracy. It is a difficult cooling method that requires advanced technology to handle the parison. Currently, when simple cooling methods such as air cooling or water film cooling cannot be used, these are unavoidably employed. In this sense, it is of great significance that the drawdown of the composition of the present invention can be prevented by a simple known cooling means such as a simple water film cooling method. This effect is due to the characteristics of the composition itself, such as the fact that, compared to polyamide resins, the composition of the present invention has a smaller drawdown, a smaller temperature dependence on changes in resin fluid viscosity, and a stronger fluid film quality. It is estimated to be. The effects that have been clarified above are not only applicable to film molding processing, but also to various types of melt extrusion processing in which the molten resin that is melted and extruded is expanded, expanded, and cooled and solidified. It is also thought to have a beneficial effect on Examples/Comparative Example 1 Polyamide resin [Toray Milan CM1041 (product name), manufactured by Toray Industries, Inc., melting point 225°C], α-olefin ionomer resin [Himiran #1652 (product name)
Mitsui Polychemical Co., Ltd.] and saponified ethylene-vinyl acetate copolymer [Soarnol E (trade name), Nippon Gosei Kagaku Co., Ltd.] were used in Table 1 in the proportions shown in Table 4. The mixture was melt-kneaded using a single-screw extruder using a screw with a dullage. The extrusion temperature was 235°C. The mixed resin composition thus prepared was extruded using a hollow die with a die diameter of 80 mm and a slit width of 1.0 mm, supercooled with a water cooling ring of 80 mm diameter to form an unstretched parison, and then simultaneously biaxially processed using the inflation method. Immediately after stretching (stretching temperature: 60° C., stretching ratio of 3 times on each vertical axis), while fixing tension in the width direction, the film was heat-treated with hot air at a surface temperature of 140° C. for 2 seconds to obtain a film. The text describes the oxygen permeability, rate of decrease in tensile strength under high humidity conditions, room temperature dimensional change rate, hot water shrinkage rate, hot water shrinkage stress, low temperature pinhole resistance, and haze (HAZE) for this film. The results are evaluated using the second method.
Shown in the table. Figure 1 is an analysis diagram of the results shown in Figure 2. Each film in Table 2 is shown in a triangular diagram showing the mixing ratio of the polyamide resin component, α-olefin ionomer resin component, and saponified ethylene-vinyl acetate copolymer component. The relationship between the component coordinate positions of the film and the comprehensive evaluation results of the film's characteristics is plotted and stratified to clarify the correlation between the two. According to Figure 1,
A resin composition that satisfies the objects of the present invention, that is, when made into a film, has low oxygen gas permeability, low rate of decrease in tensile strength under high humidity conditions, low dimensional change rate at room temperature, and high shrinkage in hot water. As for the range of resin compositions that have characteristics such as Representation of ionomer resin, saponified ethylene-vinyl acetate copolymer), point A (80, 10,
10) The resin component must be within the range surrounded by the triangle formed by connecting the three points indicated as point B (60, 30, 10) and point C (60, 10, 30) with a straight line. It is shown. In other words, one of the mixed resin compositions of the present invention includes 60 to 80% by weight of the polyamide resin component, 10 to 30% by weight of the α-olefin ionomer resin component, and 10 to 30% by weight of the saponified ethylene-vinyl acetate copolymer. However, the total amount is in the range of 100% by weight. Furthermore, from the viewpoint of achieving the above-mentioned objects of the present invention to a higher level, the above coordinate points include point D [70, 15, 15), point B (65, 20, 15), and point F.
The component resin composition is within the range surrounded by the triangle formed by connecting the three points (65, 15, 15), in other words, the polyamide resin component is 65 to 70% by weight, and the α-olefin ionomer resin component is 15 to 25% by weight. , 15 to 25% by weight of the saponified ethylene vinyl acetate copolymer component, with the total amount being 100% by weight. Example/Comparative Example 2 α of each resin of composition numbers 4, 8, and 10 in Table 2
- By replacing only the olefinic ionomer resin component with the resin shown in Table 3,
A stretched film was prepared in the same process as in Comparative Example 1, and evaluated for each evaluation item listed in Table 3, and the results are shown in Table 3. The substituted resins were ethylene-acrylic acid copolymer resin [Yukalon A221M (trade name), manufactured by Mitsubishi Yuka Co., Ltd., acrylic acid content 8.5% by weight], modified ethylene-vinyl acetate copolymer resin (anhydrous Maleic acid grafted ethylene vinyl acetate copolymer resin)
[ADMER VE205 (product name), Mitsui Petrochemical Co., Ltd.
manufactured by Mitsui Polychemical Co., Ltd.], ethylene-vinyl acetate copolymer resin [EVAFLEX260 (product name)], Mitsui Polychemical Co., Ltd.
28% by weight vinyl acetate content], ethylene-ethyl acrylate copolymer resin [NUC copolymer]
NUC6220 (trade name), manufactured by Nippon Unicar Co., Ltd., ethyl acrylate content 7% by weight] was used. According to the results in Table 3, there are three groups of resins that can replace α-olefin ionomer resins: ethylene-acrylic acid copolymer resins, modified ethylene-vinyl acetate copolymer resins, and ethylene-vinyl acetate copolymer resins. It is indicated that a seed resin or a mixture of these resins may be selected. However, even in the case of this selected group of resins, if they are used alone, they do not have the performance to replace ionomer resins, and they must be used as other components in the mixed resin component whose main component is α-olefin ionomer resin. Only when it is used in combination with a resin, it can be used as a component resin in a proportion of 10 to 30% by weight, equivalent to the α-olefin ionomer resin in the resin composition of the present invention. It shows that it can be done. Also, according to the results in Table 3, it is desirable that the amount of the main ionomer resin component of the resin component that can replace the α-olefin ionomer resin be 70%.
Other resin components (i.e., ethylene-acrylic acid copolymer resins, modified ethylene-vinyl acetate copolymer resins, ethylene-vinyl acetate copolymer resins, This indicates that it is desirable to adjust the proportion of (or mixed resin components) within a value range of 8% by weight or less. Example/Comparative Example 3 Composition No. 1 (polyamide resin single position; comparative product) and Composition No. 4 [composition of the present invention] in Table 2
A stretched film was prepared using the same process as in Example/Comparative Example 1. In this case, we focused on the conditions during the heating and heat setting treatment after stretching, and the temperature range was varied from 100℃ to 190℃ at 10℃ intervals, and the film was heat-treated at each temperature (processing time (confirmed by changing the film surface temperature) was obtained. Each of the obtained films was evaluated for hot water shrinkage rate at 90°C and room temperature dimensional change rate, and the results are summarized in Table 4. Therefore, Table 4 shows the quality level of the film obtained at each processing temperature. Figure 4 is a graph of the raw data of the results in Table 4, where the horizontal axis shows the heat treatment temperature °C, the left vertical axis shows the hot water shrinkage rate (%) of the obtained film, and the right vertical axis shows the obtained film temperature. The room-temperature dimensional change rate (%) of the obtained film is shown, and the relationship between the properties of the obtained film is shown. The solid line is
The broken line indicates number 4 (composition of the present invention) and number 1 (polyamide resin alone). According to the results in FIG. 4, both the solid line (inventive product) and the broken line (comparative product) indicate that the properties of the resulting film can be adjusted by changing the heat treatment conditions. For both resins, when trying to obtain a film with a small dimensional change rate at room temperature (good dimensional stability), the hot water shrinkage rate tends to decrease accordingly. It turns out that it is difficult to obtain a film with a small rate of change.

[Table] However, in this case, the product of the present invention is superior in terms of the gentle slope of decrease in hot water shrinkage rate with respect to increase in treatment temperature and the small level of dimensional change rate. This means that with the composition of the present invention, it is easy to obtain a film with a dimensional change rate of 2% or less (market requirement) and a relatively high hot water shrinkage rate (market requirement 26% or more). It is noteworthy that this advantage is an attribute that cannot be achieved with conventional polyamide resins. In other words, the meaning of the above characteristics is that by adjusting a series of conditions for acrylic acid and heat fixation, heat shrinkability can be achieved at a level where the room temperature dimensional change rate is relatively small (good dimensional stability). This is because it can be said to have the characteristic that various types of non-shrinkable stretched films can be freely created. Furthermore, Table 5 summarizes the results of evaluations of O ₂ TR, WVTR, and tensile strength for both the obtained film having the composition of the present invention and the film made of a single polyamide resin. In this case, O ₂ TR and tensile strength are shown so that both the values themselves under standard evaluation conditions and the magnitude of the rate of decrease with respect to humidity can be seen. According to the results of the fifth vote, the film of the composition of the present invention has O ₂ TR, WVTR and polyamide resin.
The value itself is small and has excellent gas barrier properties, and the increase (deterioration) of O ₂ TR under high humidity is also prevented. In addition, although the tensile strength itself cannot be said to be superior, it is ultimately superior because the value is prevented from decreasing under high humidity. The above results clearly demonstrate the characteristics of the composition film of the present invention. Example/Comparative Example 4 Same as Example/Comparative Example 1 except that only the composition ratio of polyamide resin, α-olefin ionomer resin, and saponified ethylene-vinyl acetate copolymer was changed to (68, 17, 15). A shrink film was created through extrusion, stretching, and heat treatment steps. On the other hand, three types of commercially available shrink wrapping films currently used in the food packaging field were obtained, and the above-mentioned evaluations were performed on these four types of films, and the results are shown in Table 6. Further, in FIG. 5, the hot water shrinkage rates of 70 DEG C. to 100 DEG C. were determined for each of the above four types of films, and the temperature dependence of the hot water shrinkage rates for each film is shown. As is clear from the results in Table 6, the film made of the mixed resin composition of the present invention is
Compared to conventional polyamide resin films,
In addition, it has excellent oxygen gas barrier properties, rate of change in tensile strength due to humidity, low-temperature pinhole resistance, haze, etc. Among others, it has extremely excellent room temperature dimensional stability and hot water shrinkage rate. I understand. Also the fifth
According to the results shown in the figure, it can be seen that the film of the composition of the present invention has a property of exhibiting a high heat shrinkage rate over a wide temperature range, particularly a high heat shrinkage rate under low temperature conditions. Therefore, it can be seen that the film of the composition of the present invention is useful in fields where low-temperature shrinkability is required, for example, in the field of tight packaging of foods such as raw meat and processed meat. Example/Comparative Example 5 Four types of resins were used as the base resin by adding polypropylene resin [Sumitomo Noblen H501 (trade name) manufactured by Sumitomo Chemical Co., Ltd.] to the three types of resins used in Example/Comparative Example 1. , JP-A-56-146758 (prior document (i)),
JP-A-54-16576 (prior document (ii)), JP-A-56-
The composition described in each of the inventions of No. 167751 (prior document (iii)) and Japanese Patent Publication No. 167-33425 (prior document (iv)) was made into a film, and an attempt was made to compare it with the film of the composition of the present invention. . The representative resin components selected from each were as described in the composition ratio section of Table 7, and a biaxially stretched film with a thickness of 40μ and 3 times the length and width was obtained in the same manner as in Experimental Example 2 and Example/Comparative Example 1. A comparative experiment was conducted with this goal in mind, and the results are summarized in Table 7. Among the evaluation items in Table 7, the specific energy during extrusion, drawdown during extrusion, and stretching stress during stretching were determined from the oxygen permeability term during the experiment in the same manner as in Example 2. The evaluation items in the lower row are
The films of each composition were evaluated by the method described in the text. The results in Table 7 are shown as comparative values with the value of the polyamide resin film as the standard (100) in order to make the comparison between good and bad easy to understand. The first thing I noticed in this comparative experiment was the difficulty in forming a film.For both compositions (iii) and (iv), it was difficult to set stretching conditions that would allow a stable film to be obtained, and the evaluation At last, we were finally able to obtain film to use. According to the results in Table 7, while maintaining the excellent properties of polyamide resin (such as transparency and tensile strength), the disadvantages of polyamide resin, such as specific energy during extrusion, size of drawdown, oxygen,
As a product that can improve to a high level in all aspects, such as high water vapor permeability, high rate of decrease in tensile strength under high humidity, and high tendency to generate pinholes at low temperatures, , it is found that those from the composition of the invention are the best. These characteristics exhibited by the composition of the present invention are previously unknown characteristics that were developed for the first time by the present inventors. In particular, the film made from the composition (iv) had low shrinkage stress and low compressive strength, and could hardly be used in the field of tight food packaging. (Effects of the Invention) As has been explained in detail and clarified above, the resin composition of the present invention has the above-mentioned structure, so that when subjected to melt extrusion processing, the resin composition of the present invention has a higher It is a highly permeable resin composition with low energy and low stretching stress during stretching, yet with improved gas barrier properties. This advantage shows that the resin composition of the present invention can be applied to various conventionally known extrusion molding processes. Particularly, for example, when the resin composition of the present invention is used for film formation, it is advantageous because the drawdown phenomenon is small and can be easily eliminated. Furthermore, when applied to stretched films, it has been made easier to manufacture tube-shaped films using the inflation method, which has traditionally been difficult to implement due to high stretching stress, and has expanded the scope of production in this field. expand the degree of freedom of During the general stretching process, the composition of the present invention can produce a film with a high hot water shrinkage rate in a region with a small dimensional change rate at room temperature, and can also produce a film with excellent low-temperature shrinkability. It is also possible to make a film with excellent dimensional stability, which has no dimensional change at room temperature, and has no dimensional change. Another characteristic of the composition of the present invention is that the humidity dependence of both mechanical strength and gas barrier properties is improved. This characteristic, together with the fact that the gas barrier properties (O ₂ TR, WVTR) and transparency are maintained at high levels, greatly expands the field of application of conventional polyamide resins to melt extrusion molded products. It is attracting attention as something that can be expanded in width.

[Brief explanation of drawings]

The attached drawings are explained below. FIG. 1 is an experimental diagram showing the component ratio of the mixed resin composition of the present invention.
(Corresponding to Examples 1 and 2) Figures 2, 3, and 4 are experimental diagrams showing characteristic examples of the compositions of the present invention. Fig. 5 (corresponding to Comparative Example 3) is an experimental diagram showing a comparison between a film having the composition of the present invention and a commercially available film (compared with Example/Comparative Example 4) Figs.
It is an electron micrograph showing the dispersion state in which resin is dispersed in particulate form within an extruded parison.

Claims (1)

[Scope of Claims] 1. In a mixed resin composition containing a polyamide resin as a main component and other resins, the polyamide resin is 80 to 60% by weight based on the total amount of resin, and the ethylene vinyl acetate copolymer is α-olefin ionomer resin [or α-olefin ionomer resin is the main component, other components are ethylene acrylic acid copolymer resin, modified ethylene vinyl acetate copolymer resin, ethylene vinyl acetate copolymer resin] A polyamide-based mixed resin composition characterized in that a resin consisting of one or more resins selected from polymer resins is mixed at a component ratio of 10 to 30% by weight (however, a total of 100% by weight). 2 The component ratio of the mixed resin is 65 to 70% by weight of polyamide resin, 15 to 25% by weight of saponified ethylene vinyl acetate copolymer, based on 100% by weight of the total amount of resin.
α-olefin ionomer resin [or α-olefin ionomer resin is the main component; other components include ethylene-acrylic acid copolymer resin, modified ethylene-vinyl acetate copolymer resin, ethylene-vinyl acetate copolymer resin,
The mixed resin composition according to claim 1, wherein the proportion of the two or more resins, which are one or more resins selected from vinyl acetate copolymer resins, is 15 to 25% by weight. 3. The content of the resin whose main component is α-olefin ionomer resin is 70% by weight or more of α-olefin ionomer resin, and ethylene acrylic acid copolymer resin and modified ethylene acetic acid account for the entire mixed resin. The mixed resin composition according to claim 1 or 2, wherein the total amount of the vinyl copolymer resin and ethylene vinyl acetate copolymer resin is 8% by weight or less. 4 When measured using a resin plate with a wall thickness of 0.4 mm.
Claim 1, which exhibits a HAZE (ASTM1003, 23°C, 50%RH) of 5% or less;
The mixed resin composition according to item 2 or 3. 5. In an extrusion molded product obtained by melting and extruding a mixed resin composition containing polyamide resin as the main component and other resins, the polyamide resin is 80 to 60% of the total amount of resin.
Weight%, saponified ethylene vinyl acetate copolymer
10 to 30% by weight, α-olefin ionomer resin [or α-olefin ionomer resin is the main component, other components are ethylene-acrylic acid copolymer resin, modified ethylene-vinyl acetate copolymer resin, ethylene-vinyl acetate 2 or more resins that are one or more resins selected from copolymer resins] are 10 to
1. A melt-extrusion molded product of a polyamide mixed resin composition, characterized in that a resin having a component ratio of 30% by weight (however, a total of 100% by weight) is melt-kneaded and extrusion-molded. 6 The component ratio of the mixed resin is 65 to 70% by weight of polyamide resin, 15 to 25% by weight of saponified ethylene vinyl acetate copolymer, and α-olefin ionomer resin [or α-olefin The main component is an ionomer resin, and the other components are one or more resins selected from ethylene-acrylic acid copolymer resin, modified ethylene-vinyl acetate copolymer resin, and ethylene-vinyl acetate copolymer resin. resin] in a proportion of 15 to 25% by weight,
The extrusion molded product according to claim 5. 7 The content of the resin whose main component is α-olefin ionomer resin is 70% by weight or more, and ethylene acrylic acid copolymer resin and modified ethylene acetic acid account for 70% by weight or more of the total mixed resin. The extrusion molded product according to claim 5 or 6, wherein the total proportion of the vinyl copolymer resin and the ethylene vinyl acetate copolymer resin is 8% by weight or less.