JPH056579B2 - - Google Patents

Description

[Detailed description of the invention]

A. Technical Field of the Invention The present invention relates to a composition in which the compatibility between a thermoplastic resin (excluding polyolefins) and an ethylene-vinyl acetate copolymer and a saponified product is significantly improved. B. Prior art and its problems Saponified ethylene-vinyl acetate copolymer (hereinafter referred to as
Blend compositions of EVOH (sometimes abbreviated as EVOH) and other thermoplastic resins (excluding polyolefins; however, thermoplastic resins excluding polyolefins are sometimes simply referred to as thermoplastic resins below) have characteristic physical properties. We are prepared. In particular, during multilayer coextrusion molding of various thermoplastic resins and EVOH, a blend composition may be used instead of the thermoplastic resin layer or the EVOH layer, or a blend composition may be used in place of the thermoplastic resin layer or the EVOH layer.
Interlayer adhesion can be improved by providing a layer of the blend composition between the EVOH layers. Alternatively, the blend composition alone may be melt-extruded,
Furthermore, molded products such as films, sheets, and bottles obtained by stretching and/or heat treatment as necessary have excellent gas barrier properties and mechanical properties. The characteristics of blend compositions of various thermoplastic resins and EVOH have been known for some time, but these compositions generally have poor compatibility, and when extrusion molded into films, sheets, bottles, etc., non-uniformity occurs. It is known that phase-separated foreign matter is likely to occur, and that this foreign matter increases especially during long-term operation, significantly impairing the appearance. Thus, despite the excellent characteristics of blend compositions of various thermoplastic resins and EVOH, the reality is that extrusion molding cannot be practically carried out at all, or even if it is possible to do so, it can only be operated for a short period of time. C Structure, Objectives, and Effects of the Present Invention The present inventors aim to eliminate such poor compatibility and to put into practical use the excellent features of such a blend composition, and to obtain a molded product with a beautiful appearance. As a result of examining various methods, thermoplastic resin (A) and
When EVOH (B) contains an appropriate amount of hydrotalcite compound (C) and is molded using this composition, the compatibility between the thermoplastic resin and EVOH is significantly improved, and the appearance is beautiful and the layer The present invention was completed by discovering that coextrusion molded products with high adhesive strength or molded products with excellent gas barrier properties and mechanical properties can be obtained. D More detailed description of the present invention The thermoplastic resin (A) referred to in the present invention is a thermoplastic resin excluding EVOH and polyolefin, and includes polyamide resin, polyester resin, polystyrene resin, polyvinyl chloride resin. , acrylic resins, polyvinylidene chloride resins, polyurethane resins, polyvinyl acetate resins, polyacetal resins, polycarbonate resins, etc. Among these, the most preferred for the present invention in terms of their effects and practical performance. Important are polyamide resins and polyester resins, followed by polyvinyl chloride resins and polystyrene resins. Examples of polyamide resins include polycapramide (nylon-6), poly-ω-aminoheptanoic acid (nylon-7), poly-ω-aminononanoic acid (nylon-9), polyundecaneamide (nylon-11), and polylaurin lactam. (nylon-12),
Polyethylenediamineazibamide (nylon)
2, 6), polytetramethylene adivamide (nylon-4, 6), polyhexamethylene adivamide (nylon-6, 6), polyhexamethylene sebamide (nylon-6, 10), polyhexamethylene dodecamide (nylon-6, 12), polyoctamethyleneazibamide (nylon-8, 6), polydecamethylene azibamide (nylon-10, 6), polydodecamethylene sebamide (nylon-10,
8), or caprolactam/laurinlactam copolymer, cabrolactam/hexamethylene diammonium adipate copolymer, lauryl lactam/hexamethylene diammonium adipate copolymer, hexamethylene diammonium adipate/hexamethylene diammonium sebacate copolymer Examples include ethylene diammonium adipate/hexamethylene diammonium adipate copolymer, caprolactam/hexamethylene diammonium adipate/hexamethylene diammonium sebacate copolymer, and the like. ,
Among these, cabrolactam/hexamethylene diammonium adipate copolymer (nylon-
6/66) has particularly excellent physical properties when blended with EVOH, and is of particular practical importance. Representative examples of polyester resins include poly(ethylene terephthalate), poly(butylene terephthalate), poly(ethylene terephthalate/isophthalate), and poly(ethylene glycol/cyclohexanedimethanol/terephthalate). Copolymerization components include diols such as ethylene glycol, butylene glycol, cyclohexanedimethanol, neopentyl glycol, and pentanediol, or isophthalic acid, benzophenone dicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenylmethane dicarboxylic acid, and propylene. Contains dicarboxylic acids such as bis(phenylcarboxylic acid), diphenyl oxide dicarboxylic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and diethylsuccinic acid. It also includes things that have been forced. Examples of the polyvinyl chloride resin include homopolymers of vinyl chloride as well as copolymers with vinyl acetate, maleic acid derivatives, higher alkyl vinyl ethers, and the like. Examples of the polystyrene resin include, in addition to a styrene homopolymer, polystyrene obtained by graft copolymerizing butadiene, a mixture of styrene-butadiene rubber, and a styrene-maleic anhydride copolymer. Furthermore, the saponified ethylene-vinyl acetate copolymer (EVOH) (B) referred to in the present invention includes any product obtained by hydrolyzing the vinyl acetate unit in a copolymer of ethylene and vinyl acetate. Those having poor compatibility with thermoplastic resins have a relatively small amount of ethylene units and a high degree of saponification (degree of hydrolysis) of vinyl acetate units. In particular, those with an ethylene unit content of 20 to 50 mol% and a vinyl acetate unit saponification degree of 96% or more, especially 99% or more, have the highest gas barrier properties among thermoplastic resins against gases such as oxygen. Since excellent containers can be obtained by using it in combination with polyolefin, it is particularly important as an object of application of the present invention. In addition, as the hydrotalcite compound constituting the composition of the present invention, in particular, M _x Al _y (OH) _2x+3y-2z (A) _Z・aH ₂ O (M is Mg, Ca or Zn, A is _CO3 or _HPO4 ,
Examples include hydrotalcite compounds which are double salts represented by x, y, z, and a are positive numbers, and among them, the following are particularly preferred. Mg ₆ Al ₂ (OH) ₁₆ CO ₃・4H ₂ O Mg ₈ Al ₂ (OH) ₂₀ CO ₃・5H ₂ O Mg ₅ Al ₂ (OH) ₁₄ CO ₃・4H ₂ O Mg ₁₀ Al ₂ (OH) ₂₂ (CO ₃ )2・4H ₂ O Mg ₆ Al ₂ (OH) ₁₆ HPO ₄・4H ₂ O Ca ₆ Al ₂ (OH) ₁₆ CO ₃・4H ₂ O Zn ₆ Al ₆ (OH) ₁₆ CO ₃・4H ₂ O These hydrotalcite compounds may be used alone or in combination of two or more. The amounts of each component (A), (B) and (C) constituting the composition of the present invention are not particularly limited and can be arbitrarily selected depending on the purpose. However, from a practical standpoint, when it comes to the composition ratio of thermoplastic resin (A) and EVOH (B), a composition with a larger amount of one of the resins exhibits distinctive physical properties such as mechanical properties and gas barrier properties. This is particularly important. For a composition with a large amount of thermoplastic resin, the weight ratio of thermoplastic resin (A):EVOH (B) is 60:40.
~99.9:0.1, especially those in the range of 70:30 to 99.7:0.3, while compositions with a large amount of EVOH include thermoplastic resin (A):EVOH (B) weight ratios of 1:99 to 40:60. In particular, it can be said that a ratio in the range of 5:95 to 30:70 is particularly important in terms of the effects of the present invention. In addition, the amount of the hydrotalcite compound (C) that improves the compatibility is determined depending on the types of components (A), (B), and (C), and the amount of the hydrotalcite compound (C) that improves the compatibility is determined depending on the type of components (A), (B), and (C). However, in most cases, the amount is 100 parts of the sum of the weights of thermoplastic resin (A) and EVOH (B) (A + B). 0.00001 to 10 parts for
In particular, it is used in a range of 0.0001 to 1 part. If the amount exceeds 10 parts, physical properties other than compatibility tend to be impaired, which is often undesirable. Further, when the component (C) is blended with the thermoplastic resin and/or EVOH in advance, the effect of use tends to be high.
An example of adding it to EVOH is 100 parts of EVOH.
Examples include those containing 0.002 to 0.5 parts of component (C). A composition containing 0.5 part of this blend and 99.5 parts of a thermoplastic resin had a remarkable compatibility-improving effect in melt molding. In this case, thermoplastic and
The amount of component (C) per 100 parts of the total weight of EVOH is
It will be 0.00001 to 0.0025 parts. (C) The amount of component is 0.00001
If the amount is less than 100%, the effect is generally small.
In this way, it can be said that when component (C) is blended with EVOH, the effect is large even if the amount added is apparently small. The blending method for obtaining the composition of the present invention is not particularly limited, and may be a method of dry blending the three components, or a method of dry blending the three components, or a method of blending component (C) with a thermoplastic resin or
All or part of EVOH is blended in advance, and it is mixed with thermoplastic resin and/or
A method for obtaining a composition consisting of the above (A), (B) and (C) by blending with EVOH can be arbitrarily selected depending on the purpose. In general, in addition to the above-mentioned method of blending with EVOH, a method of dry blending the three components or a method of blending them into thermoplastic resin in advance can be used to achieve a particularly remarkable compatibility improvement effect. be able to. In the present invention, hydrotalcite compounds
The mechanism by which (C) so significantly improves the compatibility of thermoplastic resin and EVOH during melt molding is not fully clear, but it may include rheological effects in the melt system of thermoplastic resin and EVOH, chemical effects of impurities, etc. It is presumed that component (C) acts effectively in a complex combination of components. Other additives commonly used in thermoplastic resins can be incorporated into the compositions of the present invention. Examples of such additives include antioxidants, ultraviolet absorbers, plasticizers, antistatic agents, lubricants, colorants, fillers, or other polymeric compounds, which may be incorporated into the present invention. They can be blended within a range where the effects are not inhibited. Specific examples of additives include the following. Antioxidants: 2,5-di-t-butylhydroquinone, 2,6-di-t-butyl-p-cresol, 4,4'-thiobis-(6-t-butylphenol, 2,2'-methylene -bis(4-methyl-6
-t-butylphenol, octadecyl-3-
(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate, 4,4'-thiobis-(6-
t-butylphenol) etc. Ultraviolet absorber: ethyl-2-cyano-3,3-
Diphenyl acrylate, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2
-(2'hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-
Hydroxy-4-methoxybenzophenone, 2,
2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, etc. Plasticizers: dimethyl phthalate, diethyl phthalate, dioctyl phthalate, wax, liquid paraffin, phosphate esters, etc. Antistatic agents: pentaerythritol monostearate, sorbitan monopalmitate, sulfated oleic acid, polyethylene oxide, carbo wax, etc. Lubricants: ethylene bisstearamide, butyl stearate, calcium stearate, etc. Coloring agent: carbon black, phthalocyanine,
Quinacridone, indoline, azo pigments, titanium oxide, red iron oxide, etc. Fillers: glass fiber, asbestos, mica, ballastonite, calcium silicate, aluminum silicate, calcium carbonate, etc. Examples of means for blending each component to obtain the composition of the present invention include a ribbon blender, a high-speed mixer co-kneader, a mixing roll, an extruder, and an invasive mixer. The resin composition of the present invention can be formed into a film using a well-known melt extrusion molding machine, compression molding machine, transfer molding machine, injection molding machine, blow molding machine, thermoforming machine, rotary molding machine, dip molding machine, etc. It can be molded into any molded product such as a sheet, tube, or bottle. The extrusion temperature during molding is appropriately selected depending on the type of resin, molecular weight, composition ratio, and properties of the extruder, but in many cases
The temperature ranges from 170° to 350°C. In addition, as mentioned above, the resin composition of the present invention exhibits unique characteristics in terms of adhesiveness when used as one layer of a multilayer material. When the adhesive resin layer is D and the layer of the composition of the present invention is F, E/F/E, F/E/F, F/
F/F (F in the middle layer has a high EVOH content),
F/D/E, F/D/E/D/F, P/E/P/
F, P/F/D/E/D/F/P, P/F/D/
When a layer structure such as E/D/P is adopted, a beautiful molded product with high interlayer adhesion and excellent compatibility can be obtained. In such multilayer moldings, the blend composition of the present invention can also be substituted with scraps of the multilayer molding. The multilayer molding method generally uses so-called coextrusion, in which a number of extruders corresponding to the types of resin layers are used, and the flow of melted resin in the extruders is simultaneously extruded to form overlapping layers. It is carried out by molding. Alternatively, multilayer molding methods such as extrusion coating and dry lamination may also be employed. In addition, by carrying out stretching such as uniaxial stretching, biaxial stretching, or blow stretching of a single molded article of the composition of the present invention or a multilayer molded article containing the composition of the present invention, mechanical properties and gas barrier properties can be improved. It is possible to obtain a molded product having even more distinctive physical properties. In this way, the molded product obtained using the composition of the present invention not only has a uniform blended composition and a beautiful appearance, but also has good compatibility and uniformity, so it has many excellent properties such as strength and gas barrier properties. It has many features and is of great industrial significance. Hereinafter, this will be explained in more detail with reference to Examples. Note that parts mean parts by weight. Examples 1 to 3 6/66 copolymer polyamide (66 component 15%, melting point
198℃), EVOH [ethylene unit content 33 mol%, saponification degree 99.9%, melt index (190℃,
2160g) 1.5g/10 minutes] and a hydrotalcite compound at the ratio shown in Table 1, and then an extruder with a full-flight screw having a diameter of 40mm, L/D = 24, and a compression ratio of 3.8. A flat die with a width of 550 mm was used to form a film. The film forming temperature was 190° C. to 240° C. for the extruder and 225° C. for the die. A film with a thickness of 100 μm was wound up using a take-up machine, and continuous operation was performed for 6 hours. The obtained film was uniform and showed good compatibility,
No phase-separated foreign substances with poor compatibility were observed. A 90 mm square test piece of the obtained film was heated at 85°C using a biaxial stretching test device (manufactured by Toyo Seiki Seisakusho Co., Ltd.).
After heating for 1 minute, the film was stretched 3 times in length and width at a stretching speed of 5 m/min. Stretching is carried out uniformly, and the stretched film is fixed in a wooden frame and placed in a hot air dryer.
When heat treated at 110°C, a good film with excellent strength and gas barrier properties was obtained. Table 1 also shows the evaluation of the film surface condition of the obtained film. Comparative Example 1 A film of a mixture of polyamide and EVOH was formed in the same manner as in Example 1 except that the hydrotalcite compound was not mixed. From about 30 minutes after the start of operation, many heterogeneous phase-separated foreign substances not seen in Example 1 were observed, the number of which increased with time, and the appearance of the obtained film was extremely poor. Examples 4 to 6 After dry blending polyethylene terephthalate (PET), the EVOH resin used in Example 1, and a hydrotalcite compound at the blending ratio shown in Table 2, the diameter was 40 mm and L/D = 24 compression. It was charged into an extruder having a full-flight screw with a ratio of 3.8, and a flat die with a width of 550 mm was used to form a film. The film forming temperature is 200 to 275 using an extruder.
The temperature of the die was set to 265°C, a film with a thickness of 100 μm was wound up using a take-up machine, and continuous operation was carried out for 6 hours. Table 2 shows the evaluation of the film surface condition of the obtained film. In addition, a 90 mm square test piece of the obtained film was heated at 85°C for 1 minute using a biaxial stretching test device (manufactured by Toyo Seiki Seisakusho Co., Ltd.), and then stretched at a stretching speed of 5 m/min for both length and width. Stretched twice. Stretching was carried out uniformly, and when this stretched film was fixed to a wooden frame and heat-treated at 160°C in a hot air dryer, a good film with excellent strength and gas barrier properties was obtained. Comparative Example 2 PET was produced in the same manner as in Example 4, except that the hydrotalcite compound was not mixed.
A film of a mixture of EVOH and EVOH was formed. Immediately after the start of operation, a large number of heterogeneous phase-separated foreign substances that were not observed in Example 4 were observed, the number of which increased with time, and the appearance of the obtained film was extremely poor. Examples 7 to 9 Impact-resistant polystyrene resin (melt flow index 2.2 g/10 min) (A), EVOH (B) with ethylene unit content 32.5 mol%, saponification degree 99.9 mol%, melt index 1.4 g/min ), a hydrotalcite compound (C), and a modified ethylene-vinyl acetate copolymer adhesive resin (D) in the proportions shown in Table 3 to prepare a blend product (F). This blended product (F), the above-mentioned EVOH (B) and adhesive resin (D) were charged into separate extruders, and F/D/B/D/F (film thickness ratio 15:
Co-extrusion molding of three types and five types having a composition of 1:2:1:15) was carried out to obtain a sheet. For extrusion molding, extruders B and D were equipped with a single screw with a diameter of 50 mm and L/D = 25 at a temperature of 180 to 215 °C, and F was equipped with two screws with a diameter of 100 mm and L/D = 22. A co-rotating intermeshing twin-screw extruder is used at a temperature of 150 to 220℃, and a feedblock die (width 1000mm) is used.
The temperature was set at 225°C, and a sheet with a thickness of 1000μ was obtained. twenty four
Even after continuous operation for hours, a good sheet was obtained, and no phase-separated foreign substances with poor compatibility were observed. Comparative Example 3 A sheet was obtained by coextrusion molding in the same manner as in Example 7, except that the hydrotalcite compound (C) was not used. After starting operation 1
Heterogeneous phase-separated foreign substances, which were not observed in Example 7, were observed from around 300 hrs., and their number increased over time. Example 10 Polyvinyl chloride (PVC) 80 with an average degree of polymerization of 1300
EVOH20 with an ethylene content of 44 mol%, a saponification degree of 99 mol%, and a melt index of 5 g/10 min.
part, hydrotalcite [Mg ₆ Al ₂ (OH) ₁₆ CO ₃・
A composition consisting of 0.3 parts of 4H ₂ O] and 38 parts of dioctyl phthalate was thoroughly mixed and formed into a 100 μm thick film at 215° C. using a 28-inch inverted L-shaped calendar roll. The obtained film had a good appearance, and no phase-separated foreign substances with poor compatibility were observed. Comparative Example 4 A blend film of polyvinyl chloride and EVOH was formed in the same manner as in Example 10, except that hydrotalcite was not used in Example 10. Non-uniform phase-separated foreign substances, which were not observed in Example 10, were observed on the film surface of the obtained film, and the film had a poor appearance. Examples 11-13 Polyvinyl chloride (PVC) shown in Example 10,
After dry blending EVOH and the hydrotalcite compound (C) component in the ratio shown in Table 4, film formation was performed in the same manner as in Example 10. Table 4 also shows the evaluation of the film surface condition of the obtained film.

【table】

【table】

【table】

[Table] Excellent: Shows uniform and good compatibility, and no phase-separated foreign substances are observed.
Good: Compatibility is good, but a few phase-separated foreign substances are observed in some parts.

Claims (1)

[Scope of Claims] 1 (A) Thermoplastic resin (excluding polyolefin), (B) Saponified ethylene-vinyl acetate copolymer having an ethylene unit content of 20 to 50 mol% and a saponification degree of vinyl acetate units of 96% or more. and (C) a hydrotalcite-based compound, and contains 0.00001 to 10 parts of component (C) based on 100 parts of the total weight of the resins (A) and (B). 2. The resin composition according to claim 1, wherein the thermoplastic resin (A) is a polyamide resin. 3. The resin composition according to claim 1, wherein the thermoplastic resin (A) is a polyester resin. 4. The resin composition according to claim 1, wherein the thermoplastic resin is a polystyrene resin. 5. The resin composition according to claim 1, wherein the thermoplastic resin is a polyvinyl chloride resin.