JPS6034463B2 - Multilayer laminated structure - Google Patents

Description

Detailed Description of the Invention The present invention provides a multilayer laminate structure comprising a polyolefin composition layer and a layer of at least one polymer selected from the group of nylon, thermoplastic polyester, and ethylene-vinyl alcohol copolymer. Regarding.

Crystalline resins such as nylon, thermoplastic polyester, and ethylene-vinyl alcohol copolymer have excellent transparency and gas permeation resistance, high rigidity, and good heat resistance.
It has favorable properties for packaging films and containers for foods, pharmaceuticals, etc. However, these resins have the drawbacks of high hygroscopicity and poor heat-sealing properties, and therefore are often put to practical use in the form of laminated structures with polyolefins. In such a laminated structure, the problem is how strongly the layers can be bonded together, and this is especially important when the laminated structure is used after being boiled, such as in a retort food packaging material. Coextrusion is one method for obtaining laminated structures, but polyolefin and nylon,
It has poor affinity with ethylene-vinyl alcohol copolymers and thermoplastic polyesters, and will not adhere to them using normal coextrusion molding methods. As a method for adhering a laminated structure consisting of a polyolefin and these crystalline polar resins by coextrusion, there have been previously published methods such as Japanese Patent Publication No. 51-43055 or Japanese Patent Application Laid-Open No. 50-77485, in which a part or part of a polyolefin is bonded together. A method using a modified polyolefin grafted with a wholly unsaturated carboxylic acid or its derivative has been proposed.

However, this method still does not provide sufficient adhesion over a long period of time or when used under harsh conditions, such as in chick water. In order to improve the adhesion of the above-mentioned modified polyolefin, it is also known that a rubber component is blended into the modified polyolefin.However, since rubber is easily extracted by organic solvents, such a technology is difficult to use for oil-based food packaging films or This can be a problem when used as containers. In particular, when polypropylene is used as the polyolefin, mixing rubber with the polypropylene poses a problem in that the transparency of the polypropylene is impaired. The object of the present invention is to provide a multilayer laminate structure consisting of a polyolefin layer and a nylon, thermoplastic polyester, or ethylene-vinyl alcohol copolymer layer, which has significantly improved interlayer adhesion, especially when immersed in boiling water. It is about providing.

Another object of the present invention is to provide a multilayer laminated structure that has excellent water vapor permeation resistance, gas permeation resistance, and oil resistance, and has high mechanical strength and rigidity.

Still another object of the present invention is to provide a multilayer laminate structure comprising a polyolefin layer with good transparency and a nylon, ethylene-vinyl alcohol copolymer, or thermoplastic polyester layer. That is, the present invention provides polyethylene with a crystallinity of 40% or more or polypropylene with a boiling n-heptane insoluble content of 80% or more, which is partially or entirely grafted with at least one monomer selected from unsaturated carboxylic acids or derivatives thereof. 99 to 3% by weight, and propylene content 55% to 85% by mole, heat of crystal fusion based on differential scanning calorimeter thermal analysis from 10 to 80%. , a polyolefin composition layer consisting of 70% by weight and at least one copolymer selected from the group of nylon, thermoplastic polyester, and ethylene-vinyl alcohol copolymers with an ethylene content of 15% to 60% by mole. It is a multilayer laminated structure consisting of layers.

The ethylene-vinyl alcohol copolymer used in the present invention is a polymer with a saponification degree of 90 to 100% obtained by saponifying an ethylene-vinyl acetate copolymer with an ethylene content of 15% to 60% by mole. be.

An ethylene-vinyl alcohol copolymer with an ethylene content of less than 15 mol % has a moldable temperature close to the decomposition temperature and is difficult to mold. If the ethylene content exceeds 60 mol %, the excellent properties of the ethylene-pinylic alcohol copolymer, such as gas permeation resistance and mechanical properties, will be poor, and the effect of forming a laminated structure will be lost. Ethylene with saponification degree of less than 90%
Vinyl alcohol copolymers have poor mechanical properties, oil resistance, and water resistance, and are not preferred for practical purposes. The nylon used in the present invention includes, for example, nylon 6, nylon 66, nylon 61
It is a long chain synthetic polyamide having repeating amide groups as an integral part of the polymer backbone, such as Nylon 0, Nylon 11, and Nylon 12.

The thermoplastic polyester as used in the present invention refers to a linear polyester having an ester bond obtained by condensation of a polyhydric alcohol and a polyhydric carboxylic acid, and includes polyethylene terephthalate, polybutylene terephthalate, and the like. Antioxidants, ultraviolet absorbers, antistatic agents, pigments, dyes, nucleating agents, fillers, slip agents, lubricants, retardants, plasticizers, etc. are added to nylon, ethylene-vinyl alcohol copolymers, and thermoplastic polyesters. Agents may be included to the extent that they do not impair the purpose of the present invention.

Polyethylene with a crystallinity of 40% or more, which is a raw material for the modified polyethylene used in the present invention, is an ethylene homopolymer or ethylene and other Q-olefins such as propylene, 1-butene, 3-methyl-1-butene, 1-hexene. , 4-methyl-1-pentene or other polymerizable monomers, such as vinyl acetate, with a crystallinity of 4.
0% or more, preferably 70% or more.

The degree of crystallinity in the present invention is determined according to ASTM D-61
When was the value measured using the X-ray diffraction method for the sample prepared under the conditions of 8. The polypropylene used in the same manner as polyethylene in the present invention has a density of 0.89 to 0.91 m/m, a boiling n-heptane content of 80% or more, and a melt index (ASTM-D-1238). 65, 23000
) 0.1 none, 30 propylene homopolymer, or
propylene and 30 mol%, preferably up to 10 mol% of other Q-olefins, such as ethylene, 1-butene, 1
-bentene, 3-methyl-1-butene, 1-hexeso,
A block or random copolymer with 3-methyl-1-bentene, 4-methyl-1-bentene, etc.

In the present invention, the polyethylene or polypropylene is partially or entirely graft-modified, but in the present invention, the monomer grafted to the polyethylene or polypropylene (hereinafter referred to as a graft monomer) contains an unsaturated carboxylic acid or a derivative thereof. used.

Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itaconic acid. Derivatives of unsaturated carboxylic acids include acid anhydrides, esters, amides, imides, metal salts, etc., such as maleic anhydride, citraconic anhydride, itaconic anhydride, methyl acrylate, methyl methacrylate, ethyl acrylate, and methacrylate. Ethyl acid, butyl acrylate, butyl methacrylate, glycidyl acrylate, glycidyl methacrylate, monoethyl maleate, diethyl maleate, monomethyl fumarate, dimethyl fumarate, monomethyl itaconate, itacon Acid diethyl ester, acrylamide, methacrylamide, maleic acid monoamide, maleic acid diamide, maleic acid-N-monoethylamide, maleic acid-N·N-jethylamide, maleic acid-N-monobutylamide, maleic acid-N·N-dibutylamide, fumaric acid Monoamide, fumaric acid diamide, fumaric acid-N-
Monoethylamide, fumaric acid-N・N-jethylamide, fumaric acid-N-monobutyramide, fumaric acid-N・N
Examples include -dibutylamide, maleimide, N-butylmaleimide, N-phenylmaleimide, sodium acrylate, sodium methacrylate, potassium acrylate, potassium methacrylate, and the like. Among these, maleic anhydride is most preferred. Various known methods can be used to graft the graft monomer onto polyethylene or polypropylene.

For example, it is carried out by heating polyethylene or polypropylene and grafting monomers at high temperatures in the presence or absence of a solvent, with or without the addition of a radical initiator. Other vinyl monomers such as styrene may be present during the reaction. The amount of the graft monomer to be grafted onto polyethylene or polypropylene (hereinafter referred to as grafting ratio) is preferably adjusted so that the grafting ratio of the entire composition is in the range of 10-4 to 5% by weight. From an industrial manufacturing point of view, the grafting rate is 10 in advance.
It is preferable to produce modified polyethylene with a weight percent of -2 or -1 and then mix this modified polyethylene or polypropylene with unmodified polyethylene or polypropylene because the concentration of the graft monomer in the composition can be adjusted appropriately. As for the method, it is also possible to graft a predetermined amount of graft monomer to polyethylene or polypropylene from the beginning. The propylene/1-fteso copolymer blended into the modified polyethylene or modified polypropylene in the present invention has the following characteristics.

'i) Melt index (ASTM-D-1238-
65T, 23000) preferably without 0.1, and 4
0,'ii- Propylene content: 55%, 85% by mole, preferably 60%, 82% by mole, {iiD Heat of crystal fusion: 10%, 80Joule/night, preferably 20%, 70Joules/night evening.

The propylene/1-butene copolymer used in the present invention must satisfy all of these conditions.

A resin with a propylene content of more than 85 mol % is structurally similar to polypropylene and has poor modification effects.

Resins with a propylene content of less than 55 mol % are not preferred because they have poor mechanical suitability, heat resistance, and oil resistance.

The heat of fusion is a value that correlates with the degree of crystallinity of the polymer, but propylene/1-butene copolymers with a heat of fusion exceeding 8 oule/unit have a low level of transparency, and are transparent compared to polypropylene. You can't improve your sexuality.

On the other hand, propylene with a heat of fusion of less than 10 Jo mountain e/ta
1-butene copolymers have poor mechanical properties and heat resistance;
Has a sticky feel. Therefore, the excellent properties of polyethylene and polypropylene, such as mechanical properties, oil resistance, and heat deformation resistance, are significantly impaired, so that they are not preferable for retort food applications. Especially without propylene content 60 and 82
A copolymer having a mole % and heat of fusion range of 20 to 70 Jo m/e/m is preferable because it has an excellent modifying effect. Note that the heat of fusion of the polymer in the present invention is measured by measuring the specific heat curve of the copolymer in a completely molten state (preferably the specific heat curve shown at 160° C. or higher and 240° C. or lower) using a differential scanning calorimeter. This is a value calculated using the straight line obtained by interpolation as the baseline.

The melting point and heat of fusion are measured under the following measurement conditions.

That is, after leaving the sample at 200qo for 5 minutes, at 100C
Cool to -40°C at a rate of /min and leave at -40°C for 5 minutes. After that, -4 at a heating rate of 200C'min.
Measurement is carried out from 0qo to 200°C. A propylene/1-butene copolymer having the above-mentioned properties and having a propylene content of 55 to 85 mol% is, for example, 'a} a composite containing at least magnesium, titanium and a halogen, 'b} a composite containing at least magnesium, titanium and a halogen; It is obtained by random copolymerization of propylene and 1-butene using a catalyst formed from an organometallic compound of a Group 1 to Group 3 metal and a c-electron donor. A part or all of the electron donor 'c} may be fixed to a part or all of the complex {a), or the organometallic compound 'c} may be fixed to a part or all of the complex {a) before use.
b- may be pre-contacted. Particularly preferred is an embodiment in which a part of the electron donor {c) is fixed as a complex and the remainder is added to the polymerization system as it is or is used by pre-contacting it with the organometallic compound 'b}. It is. In this case, the electron donor immobilized on the complex 'a} and the electron donor used by directly adding it to the polymerization system or by pre-contacting it with {b} may be the same or different. It's okay. Catalysts other than those mentioned above, such as those manufactured using titanium trichloride catalysts, have a high degree of crystallinity even at the same propylene content; that is, comonomers are not randomly introduced into the copolymer, so the copolymer itself is transparent. is low and undesirable. On the other hand, those manufactured using vanadium catalysts have almost no heat of crystal fusion, but
As mentioned above, such polymers have poor mechanical properties and heat deformation resistance, and cannot be used in the present invention. The polyolefin composition used in the present invention contains {a} polyethylene or polypropylene 99-free, preferably 3% by weight of polyethylene or polypropylene with a crystallinity of 40% or more grafted in part or in whole with unsaturated carboxylic acids or derivatives thereof; 90 to 5% by weight of 'b-propylene-1-butene copolymer 1
None, 7% by weight, preferably 10 to 5% by weight
The main component is a composition consisting of.

If the amount of propylene/1-butene copolymer blended is less than 1% by weight, the effect of the blending will be insufficient, and if it exceeds 7% by weight, heat deformation resistance, rigidity, and mechanical strength will be impaired, resulting in retort applications, etc. cannot be used. In addition to the above-mentioned components, the polyolefin composition used in the present invention includes weathering stabilizers, heat-resistant stabilizers, pigments, dyes, fillers, and the like.
It may contain an antistatic agent, a lubricant, a retardant, a plasticizer, etc.

In addition, other polymers other than polyolefin resins, such as
Synthetic resins such as nylon, polyester, polyvinyl chloride, epoxy resin, polyacrylate, polystyrene, polycarbonate, etc., rubbers such as polybutadiene, polyisoprene, polyisobutylene, chlorinated polyethylene, chloroprene rubber, ethylene-propylene rubber, etc. It may be included as long as it does not. Various known methods can be used to prepare the polyolefin composition used in the present invention.

For example, after mixing each component with a ribbon blender, V-type blender tumbler, Henschel mixer, etc., melting and kneading with an extruder, Banbury mixer, two rolls, kneader, etc., or melting each component in a solvent and thoroughly mixing the components, A method such as adding a poor solvent to precipitate the mixture after mixing the fly azusa may be used. The polyolefin composition layer of the present invention and nylon,
Methods for producing a laminated structure consisting of an ethylene-vinyl alcohol copolymer and a thermoplastic polyester layer include: {1-Producing each film or sheet in advance and bonding them together by thermocompression; ■Nylon; A method of extruding and laminating a molten polyolefin composition onto a thermoplastic polyester or ethylene-pinyl alcohol copolymer layer, a method of melting each leg in a separate extruder and coextruding it from the same die, etc. can be used. Above '11, [2
), in method '3', the resin temperature of the polyolefin during molding is 140qo, 300qo, especially 200℃
A range of 250 to 250 oo is preferred.

The nylon resin temperature in methods {1} and (3) is 2
00oo to 300℃, especially 24000, and 27
A range of 0oo is preferred. The resin temperature of the ethylene-vinyl alcohol copolymer is 17030, 250oo,
In particular, a range of 180oo to 23000 is preferred.
The resin temperature of the polyester is preferably in the range of 250 to 300 degrees, particularly 260 to 280 degrees. The laminated structure consisting of a polyolefin composition layer and an ethylene-vinyl alcohol copolymer layer of the present invention includes a two-layer structure having a polyolefin composition layer and an ethylene-vinyl alcohol copolymer layer as an inner layer or an outer layer; A three-layer structure in which one of the layers is an intermediate layer and another layer is sandwiched, or the above structure is further combined with a polyolefin composition or an ethylene-vinyl alcohol copolymer and a polymer having thickening properties, such as a polyolefin composition. In the case of products, unmodified polypropylene, polyethylene, ethylene/Q-olefin copolymers, etc.; in the case of ethylene-vinyl alcohol copolymers, laminate structures made of laminated layers of nylon, polyester resin, etc. Modified polyolefin/polyolefin composition/ethylene-vinyl alcohol copolymer, polyolefin composition/ethylene-vinyl alcohol copolymer/nylon three-layer structure, unmodified polyolefin/polyolefin composition/ethylene-vinyl alcohol copolymer/polyolefin Composition, four-layer structure of unmodified polyolefin/polyolefin composition/ethylene-vinyl alcohol copolymer/nylon, five-layer structure of unmodified polyolefin/polyolefin composition/ethylene vinyl alcohol copolymer/polyolefin composition/unmodified polyolefin It is possible to think about the structure.

Similarly, an example of a laminate comprising the polyolefin composition layer of the present invention and a nylon or thermoplastic polyester layer is one in which a thermoplastic polyester layer or a nylon layer is used instead of the ethylene vinyl alcohol layer in the above example. Of course, the laminated structure of the present invention is not limited to those exemplified above, but is a laminated structure containing the following components: polyolefin composition/nylon, polyolefin composition/thermoplastic polyester, or polyolefin composition/ethylene-vinyl alcohol copolymer. Various combinations are possible within this range. In these laminated structures, one or both of the layers may be uniaxially or biaxially oriented. The laminated structure of the present invention can be put to practical use as a film, sheet, pipe, hollow bottle, etc.

The laminated structure composed of the polyolefin composition of the present invention and nylon, ethylene-vinyl alcohol copolymer, or thermoplastic polyester has significantly improved interlayer adhesion, especially after dipping water treatment, and The problem of the laminate peeling off during use has been resolved.

Therefore, polyolefin/nylon, polyolefin/
Utilizing the high rigidity, mechanical strength, rainwater resistance, gas permeation resistance, water vapor permeation resistance, etc. of ethylene-vinyl alcohol copolymer or polyolefin/thermoplastic polyester laminate, packaging of vegetables, meat, dairy products, etc. It can be suitably used for applications such as packaging containers for materials, seasonings, edible oils, pharmaceuticals, etc., and packaging materials for retort foods such as curry and stew. Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples as long as the gist thereof is not exceeded.

Examples 1 to 3 [Production of propylene/1-butene random copolymer] In a stainless steel polymerization vessel equipped with a Takaazusa blade, 200 kg of anhydrous magnesium chloride, 4
Ethyl benzoate (6) and methylpolysiloxane (30) were ball milled in a nitrogen atmosphere, then suspended in titanium tetrachloride, and heated in a furnace until the titanium concentration was 0.
．． Triethylaluminum (b) was added to the polymerizer so that its concentration in the polymerization vessel was 1.0 mmol/sol, and methyl p-tolylate was added as an electron donor [c} to the polymerizer. A mixed gas of propylene and 1-butene (propylene 68 mol%) was supplied using n-hebutane as the polymerization solvent.
, 1-phthene (38 mol %) was fed at a rate of 42 mol % to carry out the copolymerization reaction at 7,000 mol %.

The propylene content of the thus obtained propylene/1-butene copolymer (hereinafter abbreviated as PBC) measured by nuclear magnetic resonance spectrum was 71.0 mol%, and the melting point was 11.
The temperature was 0°C, the heat of fusion was 50 Jume/night, and the melt index was 7.0. [Manufacture of coextrusion laminated film] In a 5-layer laminated film forming apparatus, the first layer and the fifth layer are
Polypropylene (melt index 6, hereinafter abbreviated as PP) is melted at 230°C in the first extruder for the layer, and
layer and a second extruder for the fourth layer polypropylene (
A composition prepared by blending modified polypropylene (with a melt index of 0.5) with 3% by weight of maleic anhydride (hereinafter referred to as modified PP) and PBC produced by the above method as shown in Table 1 was heated at 230°C. It melted into.

In the third extruder for the third layer, nylon 6 (trademark Amilan CMI021XF, manufactured by Toray Ran) was melted to 260 qo.
The three types of molten resins described above for the third layer are placed in a multi-manifold type die and coextruded to form a five-layer laminate film of polypropylene composition/nylon polypropylene composition/polypropylene (the thickness of each layer is (30 Buddha/20r/30 Buddha/20 Buddha/30〆) were molded. A medium-sized test piece was cut from this sheet, and after partially peeling off between the polypropylene composition layer and the nylon layer, the peel strength was measured using an Instron measuring machine at a chuck speed of 10 ratios/min. Further, a film taken out after being left in water vapor at 120° C. for 3 minutes was also tested in the same manner. The haze of the laminated film is AS
Measured by the method of TM-D-1003. Comparative Example 1 The same procedure as in Examples 1 to 3 was conducted except that a composition consisting of 95 parts by weight of PP and 5 parts by weight of modified PP was used as the polyolefin composition.

Comparative Example 2 Except for using ethylene-propylene rubber (melt index: 0.7, density: 0.88 mm/base, crystallinity: 1% or less, ethylene content: 80 mol%, hereinafter abbreviated as EPR) instead of PBC, The same procedure as in Example 3 was carried out.

The results of Examples 1 to 3 and Comparative Examples 1 to 2 are shown in Table 1. Table 1* Retort treatment 120°C-30 minutes treatment example 4~
6 High-density polyethylene (melt index 1, crystallinity 72%, hereinafter abbreviated as HDPE) and modified high-density polyethylene (melt index 12, crystallinity 78%) grafted with 2.5% by weight of maleic anhydride Polyethylene (hereinafter abbreviated as modified PE) and PB used in Example 1
After mixing in a tumbler blender in parts by weight as shown in Table 2, the mixture was granulated using an extruder at 210 mm.

This polyethylene composition was melted and supplied to a composite bottle molding die at a resin temperature of 230°C.

Meanwhile, in another extruder, nylon 6 (trademark AMILAN CMI02)
A 200cc composite cylindrical bottle with a polyethylene layer on the inside and a nylon layer on the outside (the thickness of the polyethylene layer is 0.1L) was melted and supplied to the die at a resin temperature of 260qo.
6 ribs, nylon layer thickness 0.1 skin) was molded. After cutting a medium-sized test piece from the side wall of the bottle and partially peeling off the polyethylene layer and nylon layer, the peel strength of both layers was measured using an Instron measuring machine at a chuck speed of 100 ribs/min. I asked for it. Further, test pieces taken out after immersion in 98°C boiling water for 3 minutes were also tested in the same manner. Comparative Example 3 The same procedure as in Examples 4 to 6 was conducted except that a composition consisting of 97 parts by weight of HDPE and parts by weight of modified PEa was used as the polyolefin composition.

The results of Examples 4 to 6 and Comparative Example 3 are shown in Table 2. Table 2 Examples 7 to 9, Comparative Example 4 A nylon substitute ethylene-vinyl alcohol copolymer (ethylene content 31 mol%, degree of saponification 99%) was used, and the resin temperature of the polypropylene composition was 220 qo.
The resin temperature of the ethylene-vinyl alcohol copolymer was set to 22
The same procedures as Examples 1 to 3 and Comparative Example 1 were performed except that the value was set to 000.

The results are shown in Table 3. Table 3 Examples 10 to 12, Comparative Example 5 Polybutylene terephthalate intrinsic viscosity 0.90 (o-chlorophenol 1%, 25°C) was used instead of nylon, and the resin temperature of the polypropylene composition was 23000.
The same machine as Examples 1 to 3 and Comparative Example 1 was used except that the resin temperature of polybutylene terephthalate was 26,000.

Claims (1)

[Claims] 1. Polyethylene with a crystallinity of 40% or more, partially or entirely grafted with at least one monomer selected from unsaturated carboxylic acids or derivatives thereof, or boiling n-heptane insoluble content of 80% or more of polypropylene 99 to 30% by weight, and propylene content 55 to 8%
5 mol%, propylene 1 with a heat of crystal fusion of 10 to 80 Joule/g based on thermal analysis with a differential scanning calorimeter
- a polyolefin composition layer consisting of 1 to 70% by weight of a butene copolymer; and at least one selected from the group of nylon, thermoplastic polyester, and ethylene-vinyl alcohol copolymer having an ethylene content of 15 to 60% by mole; A multilayer laminate structure consisting of a polymer layer. 2. The multilayer laminate structure according to claim 1, wherein the propylene/1-butene copolymer has a melt index in the range of 0.1 to 40. 3. The multilayer laminate structure according to claim 1, wherein the propylene content of the propylene/1-butene copolymer is in the range of 60 to 82 mol%. 4. The multilayer laminate structure according to claim 1, wherein the propylene/1-butene copolymer has a heat of crystal fusion in the range of 20 to 70 Joule/g.