JPH04830B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial Application Field The present invention is composed of a crystalline olefin resin layer and a polyamide resin or ethylene-vinyl acetate copolymer layer laminated with an intermediate adhesive resin layer interposed therebetween, and the intermediate adhesive resin is an olefin polymer. This relates to a multilayer structure that is a modified product of a coalesced mixture, and it not only has good moldability but also allows for the recycling of burrs that are generated when manufacturing multilayer containers obtained by blow molding, for example. The object is to provide a multilayer structure. Conventional technology Generally, saponified products of polyamide resin and ethylene-vinyl acetate copolymer (hereinafter referred to as "EVOH")
Although it has very good physical properties such as gas barrier properties such as oxygen, heat resistance, oil resistance, and mechanical strength, on the other hand, it has poor physical properties such as water vapor permeability, water resistance, and sealing properties, and is particularly poor in oxygen barrier properties. It has the disadvantage that its properties are significantly poor in a high humidity atmosphere. For this reason, it is used in a laminated form with various olefin resins that have excellent water vapor permeability and water resistance. By the way, as is well known, it is difficult to melt-bond barrier resins such as polyamide resins and EVOH with olefin-based resins due to their poor affinity. A method has been proposed in which a modified olefin polymer obtained by grafting a saturated carboxylic acid or a derivative thereof or a composition thereof is used as an adhesive layer between both of the above resins (for example, Japanese Patent Publication No. 49989/1989). , has been put into practical use. Now, many burrs are generated when manufacturing multilayer containers such as multilayer blow containers and multilayer sheet containers made of the barrier resin, modified olefin polymer, and olefin polymer. Since recovery greatly affects the cost of the container, burrs are often recovered and recycled into the olefinic polymer layer or modified olefinic polymer layer constituting the multilayer container. However, when burrs are recycled, the adhesive strength between the layers decreases, and especially in multilayer blow containers, the impact resistance decreases or the fusion strength of the pinch-off area decreases, resulting in a significant loss of product value. , there is a strong demand for its improvement. As a means for achieving this, specific modified ethylene, which is obtained by graft polymerizing 0.01 to 1% by weight of maleic anhydride to an ethylene-butene-1 copolymer or an ethylene-propylene copolymer with a crystallinity of 2 to 30%, is used as an intermediate adhesive resin. It has been proposed to use a polymer (Japanese Patent Publication No. 34461/1983). However, as will be described later, there are the following problems. First, in terms of moldability, it is significantly inferior to the use of other modified crystalline olefin polymers, that is, the polymer has low crystallinity or has a relatively low melting point and elastomeric properties. This is thought to be due to the fact that the modified ethylene copolymer is prone to surging phenomena and uneven ejection during the extrusion process, and as a result changes in the thickness of the adhesive layer occur very frequently. As a result, adhesive strength,
This causes a decrease in mechanical strength. Second, multilayer containers molded using the modified ethylene copolymer are insufficient in terms of heat-resistant adhesion, that is, adhesion at high temperatures; and third, they cannot be used as gasoline tanks or the like for a relatively long period of time. When used over multiple layers, interlayer adhesion is extremely inadequate. In addition, it may be possible to prevent the impact resistance from decreasing by, for example, adding several percent (for example, about 5%) of a modified olefin polymer to the olefin polymer layer in which flash is recycled. However, this method requires one-way
Although this method is satisfactory for containers of the type ``way'', it is insufficient when used under harsh conditions or for long periods of time, and it also increases the cost of materials. This is not a satisfactory method. As described above, these methods make it possible to recycle burrs, while also achieving the same physical properties as multilayer containers that do not require recycling, such as interlayer adhesion, impact resistance, pinch-off adhesiveness, heat-resistant adhesiveness, In addition to adhesive durability, moldability,
None of the economic aspects are satisfactory, and a strong demand has therefore arisen for measures which are satisfactory in all these respects. Problems to be Solved by the Invention From the above, the present invention does not have these problems (defects), that is, it is possible to recycle burrs, and it also has the same level of interlayer adhesion as a multilayer structure without recycling. It not only has good impact resistance, pinch-off adhesion, heat-resistant adhesion, and adhesion durability, but also has good moldability. The object of the present invention is to obtain a multilayer structure in which layers of polyamide resin or saponified ethylene-vinyl acetate copolymer are laminated with an intermediate adhesive resin layer interposed therebetween. Means and Effects for Solving the Problems According to the present invention, these problems can be solved by forming the crystalline olefin resin layer and the saponified layer of polyamide resin or ethylene-vinyl acetate copolymer into an intermediate adhesive resin layer. are laminated through the
The intermediate adhesive resin is a crystalline olefin polymer,
Olefin-based multicomponent polymer having a copolymerization ratio of α,β-type ethylenically unsaturated carboxylic acid ester of 0.1 to 50% by weight and a copolymerization ratio of dibasic unsaturated carboxylic acid or its derivatives of 0.05 to 20% by weight. coalescence and “ethylene-α-olefin copolymer of at least ethylene and α-olefin having 3 or more carbon atoms” (hereinafter referred to as “ethylene copolymer”)
It is a modified product obtained by treating a mixture of polymers consisting of the following with an unsaturated carboxylic acid or a derivative thereof in the presence of a radical initiator, and a mixture of a crystalline olefinic polymer in the mixture of polymers. The ratio is 5.0 to 20% by weight, the mixing ratio of the olefinic multi-component copolymer is 5.0 to 30% by weight, and the remainder is a modified part of the olefinic polymer mixture, which is an ethylene copolymer. This can be solved by a multilayer structure with The present invention will be explained in detail below. The intermediate adhesive resin of the present invention is produced as follows. (A) Crystalline olefin polymer The crystalline olefin polymer used in the present invention has a crystallinity at a temperature of 20°C [Journal of Polymer Science Vol.
Pages 17 to 26, X according to the method of (1955)
measured by line method] is 15% or more, preferably 20
% or more, more preferably 25% or more. Examples of the crystalline olefin polymer include high-density polyethylene, medium-density polyethylene, low-density polyethylene produced by a so-called high-pressure method, linear low-density polyethylene, isotactic polypropylene, polybutene-1, and poly-4. -Methylpentene-1 and crystalline ethylene-propylene copolymers. The melt flow rate (measured under conditions 4 or 14 according to JIS K7210, hereinafter referred to as "MFR") of this polymer is not particularly stipulated, but it is generally
0.01 to 100 g/10 minutes, preferably 0.02 to 80 g/10 minutes, particularly preferably 0.05 to 50 g/10 minutes. Even if MFR is less than the lower limit or exceeds the upper limit, it is unfavorable in terms of moldability. (B) Olefin-based multi-component copolymer The olefin-based multi-component copolymer used in the present invention has at least one type of α,β-ethylenically unsaturated material selected from the group consisting of acrylic acid alkyl esters and methacrylic acid alkyl esters. It is an olefin-based multi-component copolymer containing a carboxylic acid ester and a dibasic unsaturated carboxylic acid or a derivative thereof as monomer units. The number of carbon atoms in the alkyl group of the α,β-ethylenically unsaturated carboxylic acid ester is usually 1 to 10 (preferably 1 to 8), and among this α,β-ethylenically unsaturated carboxylic ester, Representative examples of acrylic acid alkyl esters include methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate. In addition, typical examples of acrylic acid alkyl esters include methyl methacrylate,
Examples include ethyl methacrylate and butyl methacrylate. Among these α,β-ethylenically unsaturated carboxylic acid esters, methyl acrylate, ethyl acrylate, butyl acrylate, and methyl methacrylate are particularly preferred. Further, among dibasic unsaturated carboxylic acids or derivatives thereof, the dibasic unsaturated carboxylic acid usually has at most 40 carbon atoms, preferably 35 or less. Representative examples of the dibasic unsaturated carboxylic acids include maleic acid, itaconic acid,
Mention may be made of 5-norbornene-2,3-dicarboxylic acid and fumaric acid. Typical examples of derivatives of dibasic unsaturated carboxylic acids include acid anhydrides, esters, and amide compounds of the dibasic unsaturated acids, and their metals (metals include usually alkali metals and groups A and A of the periodic table). Group B metals, such as sodium, magnesium, calcium, zinc) salts. Suitable examples of these dibasic unsaturated carboxylic acids and their derivatives include maleic acid, maleic anhydride, 5-norbornene-2,3-dicarboxylic acid and 5-norbornene-2,3-dicarboxylic anhydride. Furthermore, the number of carbon atoms in the olefin is generally at most 12, and preferably 8 or less. Representative examples of desirable olefins include ethylene, propylene and butene-1, with ethylene being most preferred. The copolymerization ratio of olefin in this multi-component copolymer is 30 to 99.85% by weight, particularly preferably 40 to 98.5% by weight. In addition, the copolymerization ratio of α, β-ethylenically unsaturated carboxylic acid ester is 0.1 to 50.
% by weight, preferably 1.0 to 50% by weight. Furthermore, the copolymerization ratio of the dibasic unsaturated carboxylic acid or its derivative is 0.05 to 20% by weight as a total amount thereof, particularly preferably 0.5 to 10% by weight. α, β− in this multicomponent copolymer
If the copolymerization ratio of the ethylenically unsaturated carboxylic acid ester and the dibasic unsaturated carboxylic acid or its derivative is less than the respective lower limits, the adhesiveness of the resulting modified olefin polymer will not necessarily be satisfactory. On the other hand, if the upper limit is exceeded, the softening point of the multi-component copolymer will increase, the fluidity will decrease, and it will not only become difficult to modify (process) the unsaturated carboxylic acid or its derivative as described below. It is also economically unfavorable. Melt flow index of this multi-component copolymer [measured under conditions 4 according to JIS K7210,
(hereinafter referred to as "MFR") is usually 0.01 to 100g/10
minutes, preferably 0.05 to 100 g/10 minutes, particularly preferably 0.1 to 50 g/10 minutes. MFR
When using a multi-component copolymer with less than 0.01g/10min,
Processability is not good. On the other hand, if it exceeds 100 g/10 minutes, moldability is poor. This multi-component copolymer is produced using the well-known radical high-pressure polymerization method, for example, by polymerizing each monomer under high pressure (generally 500 to 2500 kg/cm ² ) and high temperature (generally 120 to 260°C). It can be easily produced by radical polymerization using a chain transfer agent depending on the situation. (C) Ethylene copolymer Furthermore, the ethylene copolymer used in the present invention has at least ethylene and 3 carbon atoms.
a copolymer with more than one α-olefin,
For example, using a Ziegler-Natsuta catalyst, especially a catalyst consisting of a vanadium compound such as vanadium oxytrichloride or vanadium tetrachloride, and an organoaluminum compound, ethylene can be
50% or more and α-olefin is 50% or less, preferably 75 to 95% ethylene and 25 to 95% α-olefin
5% by copolymerization.
Furthermore, a multicomponent copolymer obtained by copolymerizing ethylene and α-olefin with a third component described later can also be used. The number of carbon atoms in α-olefin is usually 12 or less, and typical examples include propylene, butene-
1, hexene-1, decene-1 and 4-methylpentene-1, among which propylene and butene-1 are preferred. Further, as the third component, 1,4-pentadiene, 1,5-
Hexadiene and 3,3-dimethyl 1,5-
Linear or branched diolefins containing two double bonds at the ends such as hexane diene, 1,4-hexadiene and 6-methyl-
Linear or branched diolefins or bicyclo[2,2,1]-heptene containing only one double bond at the end, such as 1,5-heptadiene
Examples include those having a double bond such as cyclic diene hydrocarbons such as 2 (norbornene) and its derivatives (eg, ethylidenenorbornene, methylenenorbornene, vinylnorbornene). The content of the third component in the multicomponent copolymer obtained by copolymerizing the third component is usually 5 to 30 in terms of iodine value. Mooney viscosity of this ethylene copolymer
ML ₁₊₄ (100℃) is generally 10-150,
Especially desirable is something between 25 and 100. In order to produce a mixture of polymers for producing the intermediate adhesive resin of the present invention, these crystalline olefin-based polymers, olefin-based multi-component copolymers, and ethylene-based copolymers are mixed at the mixing ratios described below. Alternatively, dry blending may be performed in advance and the resulting mixture may be melt-kneaded. (D) Mixing ratio The mixing ratio of the crystalline olefin polymer in this mixture is 5.0 to 20% by weight, preferably 5.0 to 18% by weight, and particularly preferably 5.0 to 15% by weight. If the mixing ratio of the crystalline olefin polymer in this mixture is less than 5.0% by weight, the resulting modified product will have insufficient heat-resistant adhesion and moldability. On the other hand, if it exceeds 20% by weight, the adhesiveness of the resulting modified product will be insufficient, the improvement in impact resistance will be insufficient, and the fusion strength at the pinch-off portion will be poor. Further, the mixing ratio of the olefinic multi-component copolymer in the mixture is 5.0 to 30% by weight, preferably 5.0 to 27% by weight, and particularly preferably 5.0 to 25% by weight. If the mixing ratio of the olefin-based multi-component copolymer in the mixture is less than 5.0% by weight, not only the adhesiveness of the resulting modified product will be insufficient, but also the impact resistance will be insufficient, and the fusion strength at the pinch-off portion will be insufficient. not good. Therefore, the mixing ratio of the ethylene copolymer in the mixture is 90 to 50% by weight, preferably 90 to 55% by weight, and particularly preferably 90 to 60% by weight. If the mixing ratio of the ethylene copolymer in the mixture exceeds 90% by weight, the resulting modified product will be insufficient in terms of heat-resistant adhesion and moldability.
On the other hand, if the amount is less than 50% by weight, the improvement in impact resistance is insufficient and the fusion strength at the pinch-off portion is insufficient. The mixture thus obtained is treated with an unsaturated carboxylic acid or a derivative thereof in the presence of a radical initiator to produce a modified olefinic polymer which is the intermediate adhesive resin of the present invention. I can do it. (E) Unsaturated carboxylic acids or derivatives thereof The unsaturated carboxylic acids or derivatives thereof used to treat (modify) the mixture include monobasic unsaturated carboxylic acids, the dibasic unsaturated carboxylic acids, and their derivatives. Mention may be made of metal salts, amides, imides, esters and anhydrides of unsaturated carboxylic acids. Among these, the number of carbon atoms in monobasic unsaturated carboxylic acids is usually at most
The number is 30, and 25 or less is particularly preferable. Representative examples of monobasic unsaturated carboxylic acids include acrylic acid and methacrylic acid. Also,
Typical examples of dibasic unsaturated carboxylic acids and their derivatives include maleic acid, fumaric acid, itaconic acid, and 5-norbornene-2,3-dicarboxylic acid as dibasic unsaturated carboxylic acids, and maleic anhydride as their anhydrides. Acids, 5-norbornene-2,3-dicarboxylic anhydride and tetrahydrophthalic anhydride, monoethyl or diethyl maleate and glycidyl methacrylate as esters thereof, and maleimide as imide. Among these unsaturated carboxylic acids or derivatives thereof, anhydrides of dibasic unsaturated carboxylic acids are preferred, and maleic anhydride is particularly preferred. (F) Radical initiator Furthermore, the decomposition temperature of the radical initiator used in the present invention with a half-life of 1 minute is usually 100°C or higher, preferably 105°C or higher, and particularly
A temperature of 120°C or higher is preferable. Representative examples of suitable radical initiators include diwalnut peroxide, benzoyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(tert-butyl-peroxy).
Examples include organic peroxides such as hexane, 2,5-dimethyl-2,5-di(tertiary-butylperoxy)hexane-3, lauroyl peroxide, and tertiary-butylperoxybenzoate. (G) Usage ratio The usage ratio of the unsaturated carboxylic acid and its derivative and the radical initiator to 100 parts by weight of the mixture is usually as follows. For unsaturated carboxylic acids and derivatives thereof, their total amount is 0.01 to 5.0 parts by weight,
It is preferably 0.05 to 3.0 parts by weight, particularly preferably 0.1 to 2.0 parts by weight. The usage ratio of unsaturated carboxylic acids and their derivatives is 0.01 as their total amount.
If the amount is less than 1 part by weight, the adhesiveness of the resulting modified olefin polymer mixture will be insufficient. On the other hand, if the amount exceeds 5.0 parts by weight, there is a risk that decomposition or crosslinking reactions may occur during the production of modified olefin polymer mixtures. Further, in the case of a radical initiator, the amount is 0.001 to 1.0 parts by weight, preferably 0.01 to 1.0 parts by weight, and especially 0.01 to 0.5 parts by weight. When the proportion of the radical initiator used is less than 0.001 parts by weight, the modification effect is not sufficiently exerted, and not only does it take a long time to complete the modification, but also unreacted substances are mixed. On the other hand, if it exceeds 1.0 parts by weight,
It is undesirable because it causes excessive decomposition or crosslinking reaction. (H) Method for Modifying Olefinic Polymer Mixtures The modified olefinic polymer mixture of the present invention can be produced by known means for producing this type of olefinic polymer. Typical manufacturing methods include aromatic hydrocarbon compounds such as xylene and toluene, hexane,
A method of manufacturing by heating and mixing the olefinic polymer mixture, an unsaturated carboxylic acid or a derivative thereof, and a radical initiator in a solvent such as an aliphatic hydrocarbon compound such as heptane, and a method of manufacturing the olefinic polymer mixture, unsaturated A carboxylic acid or its derivative and a radical initiator are mixed in advance under essentially non-crosslinking conditions, and the resulting mixture is mixed using a kneader commonly used in the field of synthetic resins, such as a screw extruder, Banbury mixer, or kneader. The latter method is preferably adopted from the viewpoint of operation method and economy. In the latter case, the temperature conditions for modification are appropriately selected taking into consideration the deterioration of the olefinic polymer, the decomposition of the unsaturated carboxylic acid or its derivative, the decomposition temperature of the organic peroxide, etc. -350°C, preferably 150-320°C, particularly preferably 180-300°C. A layer of the crystalline olefin polymer (crystalline olefin resin) used to produce the modified product is interposed between the polyamide resin or ethylene-based layer of the modified product, which is the intermediate adhesive resin obtained in this way. The multilayer structure of the present invention can be produced by laminating layers of saponified vinyl acetate copolymers. In this case, the crystalline olefin resin may be the same as the crystalline olefin polymer used for producing the modified product, or may be different. When this crystalline olefin resin is used for fuel containers such as gasoline tanks, high-density (density 0.935 g/cm ³ or more) polyethylene is preferred. The MFR of this crystalline olefin resin is particularly preferably within the same range as above. (J) Polyamide resin The polyamide resin used in the present invention is
It is a linear polymer compound having an acid amide bond (-CONH-), and can be roughly divided into polyamides obtained by polycondensing dibasic acids and diamines, and polyamides obtained by self-polycondensing cyclic lactams and amino acids. Polyamides obtained by this process are known. Representative examples of the former include polycondensates of hexamethylene and adipic acid (nylon 6-6), polycondensates of hexamethylene diamine and sebacic acid (nylon 6-10), and polycondensates of hexamethylene diamine and dodecanoic acid. Polycondensate (nylon 6-12), polycondensate of hexamethylene diamine and terephthalic acid (nylon 6T), polycondensate of xylene diamine and adipic acid (XD
-6 nylon) and a polycondensate of xylene diamine and sebacic acid (XD-10 nylon). Representative examples of the latter include self-polycondensates of caprolactam (nylon 6), 10
-Self-polycondensates of aminoundecanoic acid (nylon 11) and self-polycondensates of laurinlactam (nylon 12). Further, although the degree of polymerization of the polycondensate and mixed polyamide resin mainly composed of these components is not limited, the relative viscosity is generally from 1.0 to 6.0, and preferably from 1.5 to 5.5. These polyamide resins are manufactured industrially and are used in a wide range of fields, and their manufacturing methods, types, various physical properties, molding methods, etc. are described in "Plastics" edited by Shunsuke Murahashi, Ryohei Oda, and Minoru Imoto. It is well known from pages 521 to 548 of "Handbook" (published by Asakura Shoten in 1981), pages 521 to 548. (K) Saponified product of ethylene-vinyl acetate copolymer Also, ethylene-vinyl acetate copolymer used in the present invention
Saponified vinyl acetate copolymer (EVOH) is a copolymer of ethylene and vinyl acetate (EVA)
It can be produced by saponifying it by a commonly used method. The copolymerization ratio of ethylene in EVA is generally 20 to 80 mol%, particularly preferably 25 to 75 mol%. If the copolymerization ratio of ethylene is less than 20 mol%, there is a problem in terms of moldability. On the other hand, if it exceeds 80 mol%,
The resulting multilayer structure is unsatisfactory in terms of its barrier properties against oxygen, etc. In addition, the degree of saponification is usually 90%
or more, especially 95% or more is desirable. If the degree of saponification is less than 90%, the obtained multilayer structure will not have good barrier properties against oxygen, etc. The polyamide resin and EVOH, which are the barrier resins of the present invention, may be used individually or in combination. Furthermore, polyamide resin or EVOH and polyvinyl alcohol can be blended and used as long as both resins are compatible and melt molding is possible. In producing the multilayer structure of the present invention, the crystalline olefin resin, modified product, and polyamide resin or EVOH that are the constituent components are stabilized against heat, light (ultraviolet rays), and oxygen, which are commonly used in the respective resin fields. agent,
Various additives such as plasticizers, lubricants, fillers, antistatic agents, and pigments (coloring agents) may be added to the extent that they do not impair the production and physical properties of the multilayer structure. Further, these resins may be used alone or in combination of two or more. (L) Multilayer structure and its manufacturing method The multilayer structure of the present invention is manufactured by a widely known method such as multilayer blow molding or molding from a sheet by multilayer T-die method. A typical method using multilayer blow molding is the 22nd “Plastics Age” method.
Vol. 59-62 (September 1976 issue), Volume 27, pp. 80-84 (April 1981)
For example, "Plastics" Vol. 32, pp. 49-54 (September 1981 issue); "Food Packaging", pp. 115-118 (September 1981 issue); As stated in the October 1983 issue),
In this method, a multilayer sheet is manufactured in advance, and a multilayer container is manufactured by subjecting this sheet to various types of thermoforming (for example, vacuum forming, pressure forming, vacuum pressure forming). The layer structure of the multilayer structure obtained by this method includes a crystalline olefin resin layer,
If a layer of polyamide resin or a saponified product of ethylene-vinyl acetate copolymer (i.e., EVOH) is used as an intermediate adhesive resin (modified product) layer, typical examples are //, /
Examples include //, /////, etc. In addition, the polyamide resin layer is -A,
If the EVOH layer is -B and the polyester resin layer with good mutual adhesion is -C, -A/-B//, //-
A/-B//-A, -C/-A/
/, -C/-B//, etc. may be used. During this multi-layer blow molding, burrs usually vary depending on the shape and wall thickness of the container per 100 parts by weight of the blow container.
Although it varies depending on the molding conditions, it is usually generated in an amount of about 10 to 150 parts by weight. In the present invention, this burr layer has good miscibility with the crystalline olefin resin and the intermediate adhesive resin, so it is mixed with the crystalline olefin resin and the intermediate adhesive resin.
It can be collected and used. When mixing burrs into crystalline olefin resin, the resin
The amount per 100 parts by weight is generally not more than 100 parts by weight, preferably 5 to 70 parts by weight, particularly preferably 5 to 50 parts by weight. In addition, when mixed with intermediate adhesive resin, it is usually
The amount is 2000 parts by weight or less, preferably 50 to 1000 parts by weight, and particularly preferably 50 to 500 parts by weight.
Note that this burr is preferably mixed into the crystalline olefin resin. If too much burr is mixed in with the crystalline olefin resin, it will not only reduce the impact resistance of the resulting multilayer container, especially at low temperatures;
The strength of the fusion bond at the pinch-off portion decreases. On the other hand, if it is mixed into the intermediate adhesive resin, it is not preferable because the interlayer adhesive strength with the polyamide resin layer etc. will decrease. Furthermore, when a sheet is molded by the multilayer T-die method, it can be manufactured in the same manner as described above. At this time, the layer structure is the same as in the case of the multilayer blow molding described above. When forming this multilayer sheet, the cuts at the edges (both ends of the sheet) generally cause burrs due to edge loss, and although it varies depending on the thickness of the sheet and the forming conditions, per 100 parts by weight of the multilayer sheet,
Generally, about 5 to 20 parts by weight of burrs are generated.
In multilayer sheet molding, this flash can be used as a separate layer using a dedicated extruder. One example is to interpose it between a crystalline olefin resin layer and an intermediate adhesive resin.
If we take the burr layer here, for example //
It is a multilayer sheet having a layer structure of /-B//. There are many cases where burr recycling methods are used in this way, but in this case, new equipment for extrusion molding the burr layer is required, process control during molding, setting of conditions before and after molding, etc. Increased operations such as resin purging, etc.
It is also unfavorable from an economic point of view. Therefore, even in the case of this multilayer sheet molding, it is preferable to recycle the generated burrs into the crystalline olefin resin, the intermediate adhesive resin, or both, as in the multilayer blow molding method described above. In the case of the present invention, not only is this recycling possible, but even if the burrs are recovered and used, they can be mixed in at the mixing ratio described above based on the same theory as in the case of multilayer blow molding. Regardless of the multilayer blow molding described above or the formation of a multilayer sheet, this burr usually occurs in the form of lumps or sheets, so it is necessary to cut it into appropriate sizes using a crusher or sheet cutter commonly used in the plastics field. The above-mentioned mixture is made into granules, powder or rectangles and mixed with powdered or pelleted crystalline olefin resin or intermediate adhesive resin (modified product) using a mixer such as a tumbler, V-blender or Henschel mixer. Used as a dry blend. Furthermore, if necessary, the dry blend (mixture) may be melt-kneaded using a kneader such as an extruder in order to further improve the uniformity. When recycling the resin into an olefin resin layer, a method is adopted in which the resin is melt-extruded using a screw that has better kneading properties. In the case of multilayer blow molding as described above or in the case of molding a multilayer sheet, the thickness of each layer of the obtained multilayer structure varies depending on the use and required characteristics, and is not particularly limited. The thickness of the polyamide resin or EVOH layer is usually 0.1 to 50% of the thickness of the crystalline olefin resin.
In terms of economy, 1 to 30% is particularly preferable. Generally, the thickness of the crystalline olefin resin is 0.03 to 10 mm, preferably 0.05 to 7 mm. The thickness of the modified material layer and the polyamide resin or EVOH layer is usually 0.005 to 2 mm, particularly 0.01 to 2 mm.
0.5mm is preferred. The multilayer structure obtained in this way uses polyamide resin or EVOH as the barrier resin, so it has excellent gas barrier properties such as oxygen, gasoline and diesel oil, oil resistance, and solvent resistance. It can be used in many ways. EXAMPLES AND COMPARATIVE EXAMPLES The present invention will now be explained in more detail with reference to Examples. In Examples and Comparative Examples, molding processability was determined by extruding each resin at a constant screw rotation speed using three types and five types of dies, taking parisons under the same conditions, and examining unevenness in the thickness of the adhesive layer. , judged according to the following categories. Good (○): Parison thickness unevenness setting value ±10
Within % Slightly inferior (△): Parison wall thickness unevenness Setting value ±10 to 20% Poor (×): Parison wall thickness unevenness Setting value ±20
% or more Note that this set value means the theoretical thickness determined in advance from the relationship between the screw rotation speed and the discharge amount of the extruder. In addition, “interlayer adhesion” is 23℃ and 50%
The resistance value (Kg/ cm) was calculated. Furthermore, "heat-resistant adhesion" is measured by sampling a 100 mm x 50 mm section from the flat side of a blow container or from the sheet using a cutter knife.
Leave it in the oven at 100±2℃ for 2 days and 90~
After being immersed in hot water at 95° C. for 8 hours, the adhesive strength between the adhesive layer and the barrier layer was measured under the same conditions as the interlayer adhesion described above. In addition, "drop impact strength" is measured by filling a blow container with antifreeze to almost 100%, capping it, leaving it in a cryostat at room temperature or -35°C for 24 hours to adjust the condition, and then dropping it from a height of 10 meters. The number of broken samples among the 10 samples was determined by observing the occurrence of fractures and cracks, and the condition of the weld part. Therefore, 10/10 in the column of "drop strength" in the table means that all were broken or cracked, and 0/10 means that all were not broken or cracked. In addition, the "strength of the weld part" is determined by visually observing the delamination of the weld part (pinch-off part). If there is no abnormality, it is rated "good", and depending on the degree of abnormality such as peeling or cracking, it is "slightly good" or "slightly poor". ” or “defective”. Examples 1 to 4, Comparative Examples 1 to 4 MFR is 1.1 g/10 minutes and density is 0.950
g/ ^cm3 high-density polyethylene [hereinafter referred to as “HDPE
(1)], an ethylene-methyl methacrylate-maleic anhydride ternary copolymer in which the copolymerization ratio of methyl methacrylate is 8.0% by weight and the copolymerization ratio of maleic anhydride is 2.5% by weight. (MFR3.5g/10 minutes, hereinafter referred to as "EMMAH")
and the copolymerization ratio of propylene is 27% by weight, the Mooney viscosity (ML ₁₊₄ , 100°C) is 65,
Moreover, the ethylene-propylene copolymer (hereinafter referred to as "EPC(1)") has a crystallinity of 0.6% by X-ray diffraction method.
0.010 parts by weight of 2.5-dimethyl-2.5-di(tertiary-butylperoxy)hexane (hereinafter referred to as "2.5B ) was added and dry blended for 1.5 minutes using a Henschel mixer. 0.375 parts by weight of maleic anhydride was added to each of the resulting mixtures, and dry blending was performed for 3 minutes using a Henschel mixer. Each mixture thus obtained was processed using a non-vent extruder (diameter 40 mm).
Each modified olefin polymer was produced by performing a kneading reaction and extrusion while melting (Examples 1 to 4, Comparative Examples 1, 2, and 4). The amount of maleic anhydride grafted in each modified olefin polymer thus obtained was determined by infrared absorption spectroscopy. Instead of EPC (1) used in Examples 1 to 4, the copolymerization ratio of propylene was 24% by weight,
and Mooney viscosity (ML ₁₊₄ , 100℃) is 35,
Moreover, the ethylene-propylene copolymer (hereinafter referred to as "EPC(2)") has a crystallinity of 2.5% by X-ray diffraction method.
A modified olefin polymer was produced in the same manner as in Examples 1 to 4, except that the following was used (Comparative Example 3). Each modified olefin polymer thus obtained was interposed as an adhesive layer between the innermost layer and the intermediate layer and between the outermost layer and the intermediate layer, and the innermost layer and the outermost layer were formed using high-density polyethylene (Showa Denko Co., Ltd.). Polyamide 6 (manufactured by Toray Industries, Inc., product name Amilan CM1046) was used as the intermediate layer (barrier layer), and a blow molding machine equipped with three extruders and a multilayer die with three types and five layers was used. A 3.5-inch multilayer bottle with a total average wall thickness of 2.4 mm (the thickness composition ratio is 45.4% for the innermost and outermost layers, 3.3% for each adhesive layer, and 2.5% for the middle layer) was molded. The moldability, interlayer adhesion, heat-resistant adhesion, and drop impact strength at -35°C of each container were measured. In addition, the amount of grafted maleic anhydride (hereinafter referred to as "g-MAH") in the modified olefin polymer was measured. The results are shown in Table 1. In addition, the strength of the weld portion of each bottle obtained in all Examples and Comparative Examples was measured. The results are shown in Table 1.

[Table] Examples 5 to 11, Comparative Examples 5 to 9 Each modified olefin polymer (types are shown in Table 2) used as the adhesive layer in Examples 1 to 4 and Comparative Examples 1 to 4 was used. However, Example 6 used a composition consisting of 50 parts by weight of the modified product (A) and 50 parts by weight of the burr generated in Example 1, and Example 11 used a composition consisting of 50 parts by weight of the modified product (D) and 50 parts by weight of the burr generated in Example 1. A composition consisting of 50 parts by weight of burrs generated in In addition, the density is 0.944g/ ^cm3 , and
High-density polyethylene (hereinafter referred to as "HDPE(a)") having an MFR of 5.3 g/10 minutes and Examples 1 to 4
And each burr obtained in Comparative Examples 1 to 4 (shown in Table 2 by Example or Comparative Example number) was used to produce a composition part having the composition ratio shown in Table 2. In Examples 1 to 4 and Comparative Examples 1 to 4, the compositions produced as described above were used instead of the high-density polyethylene used as the innermost layer and the outermost layer, and the modified olefin was used as the adhesive layer. Multilayer bottles were molded in the same manner as in Examples 1 to 4 and Comparative Examples 1 to 4, except that the modified olefin polymer obtained as described above was used instead of the olefin type polymer. The interlayer adhesion and heat-resistant adhesion of each of the obtained multilayer bottles were measured. The results obtained are shown in Table 3. In addition, drop impact strength was measured at room temperature and -35°C. The results are shown in Table 3. Furthermore, the strength of the weld portion was measured. The results are shown in Table 3.

【table】

【table】

[Table] Example 12, Comparative Example 10 High-density polyethylene with an MFR of 0.3 g/10 min and a density of 0.953 g/cm ³ as the innermost layer and outermost layer [hereinafter referred to as "HDPE(b)"] using
Example 1 except that a saponified product of ethylene and vinyl acetate copolymer (manufactured by Kuraray Co., Ltd., trade name EVAL F) was used as the barrier layer, and the modified polymer (C) used in Example 3 was used as the adhesive layer. A multilayer bottle was manufactured in the same manner as in Example 1. The resulting multilayer bottle had a total thickness composition ratio of 89.9% for the innermost and outermost layers, 4.3% for the barrier layer, and 5.8% for the adhesive layer (Example).
12). A composition consisting of 30 parts by weight of burrs generated during the production of the multilayer bottle in Example 12 and 70 parts by weight of HDPE(b) was produced. Instead of HDPE(b) used as the innermost layer and outermost layer in Example 12,
A multilayer bottle was produced in the same manner as in Example 12, except that the obtained composition was used. The interlayer adhesion between the barrier layer and the adhesive layer of the thus obtained multilayer bottle was 2.7 Kg/cm.
The heat-resistant adhesion was 2.0 Kg/cm. Further, when a drop impact strength test was conducted at a temperature of -35°C, it was 0/10. In addition, the modified polymer (F) used in Comparative Example 2 was used instead of the modified polymer (C) used as the adhesive layer in producing the multilayer bottle in Example 12. A multilayer bottle was produced in the same manner (Comparative Example 10). Burrs generated during manufacturing this multi-layer bottle
A composition consisting of 30 parts by weight and 70 parts by weight of HDPE(b) was prepared. A multilayer bottle was produced in the same manner as in Comparative Example 10, except that this obtained composition was used instead of HDPE (b) used as the innermost layer and outermost layer in Comparative Example 10. The interlayer adhesion between the barrier layer and the adhesive layer of the thus obtained multilayer bottle was 1.8 Kg/cm.
The heat-resistant adhesion was 1.1 Kg/cm. In addition, when tested for drop impact strength at a temperature of -35°C, it was 1/10th of that. Effects of the Invention The multilayer structure of the present invention exhibits the following effects (features). (1) Lamination of a crystalline olefin polymer and a saponified product of polyamide resin or ethylene-vinyl acetate copolymer using a modified olefin polymer mixture that has excellent moldability and adhesive properties. Because of this structure, it is possible to manufacture multilayer containers of unprecedented quality. (2) A multilayer container obtained by recycling burrs generated during the manufacturing of the multilayer container into a crystalline olefin resin or an adhesive layer has the same performance as a multilayer container without recycling burrs. level, and therefore offers excellent economic advantages. (3) Therefore, not only multilayer containers but also large containers (eg, gasoline tanks, drums, industrial chemical cans) that require long-term durability and good performance have become possible with the present invention.

Claims (1)

[Claims] 1 A crystalline olefin resin layer and a polyamide resin or a saponified layer of ethylene-vinyl acetate copolymer are laminated via an intermediate adhesive resin layer, and the intermediate adhesive resin is a crystalline olefin polymer, Olefinic multi-component in which the copolymerization ratio of α,β-type ethylenically unsaturated carboxylic acid ester is 0.1 to 50% by weight, and the copolymerization ratio of dibasic unsaturated carboxylic acid or its derivative is 0.05 to 20% by weight Treating a copolymer and a mixture of polymers consisting of an ethylene-α-olefin copolymer of at least ethylene and an α-olefin having 3 or more carbon atoms with an unsaturated carboxylic acid or a derivative thereof in the presence of a radical initiator. It is a modified product obtained by
The mixing ratio of olefin-based multi-component copolymer is 5.0 to 30
% by weight, and the remainder is a modified olefin polymer mixture, the remainder being an ethylene-α-olefin copolymer.