KR100266853B1 - Film, sheet and other products molded from the compositions of polyolefin/polyvinylalcohol and multi-layer product using them - Google Patents

Abstract

PURPOSE: A composition of polyolefin and polyvinylalcohol is provided to improve thermal adhesiveness of films, sheets and mold and produce multilayer-products as a gas and organic solvent barrier at low costs. CONSTITUTION: The composition for a gas and organic solvent barrier film is comprised of 1-80 wt.% of polyolefin and 20-99 wt.% of polyvinylalcohol; a high molecular compatibilizer (3-40 wt.%), a low molecular compatibilizer (0.1-5 wt.%), a reaction initiator for compatibilizer and polyolefin (0.01-0.5 wt.%), and a mixture of the high and low molecular compatibilizers and the reaction initiator; 3-50 wt.% of plasticizer selected from a group of glycerin, ethyleneglycol, diethylglycol, propyleneglycol, dipropyleneglycol, a mixture of glycerin and water, polyethyleneglycol, polypropyleneglycol, trimethylolpropane, triethyleneglycol, and isopropanol; 1-10 wt.% of processing aid selected from a group of acryl oligomer, phosphate, calcium stearate iron stearate, magnesium stearate, stearic acid, paraffin wax, and polyethylene wax; 0.01-5 wt.% of antioxidant selected from a group of phenol, phosphate, calcium-iron-tin organic compound, dioctyltin malate, and dioctyltin mercaptide.

Description

Films, sheets, molded articles formed from mixed compositions of polyolefin and polyvinyl alcohol, and multi-layered products using them

The present invention relates to a film, a sheet, a molded article and a multilayer structure product using the same having excellent gas and organic solvent barrier properties. Specifically, a polyolefin and a polyvinyl alcohol are used as a compatibilizer, an initiator, a plasticizer, a processing aid and an antioxidant. The present invention relates to a film, a sheet, a molded article, and a multi-layered product made by melting a mixed composition made by addition.

The gas refers to a gaseous state of an organic solvent such as oxygen, nitrogen, and the like, and the organic solvent means hydrocarbons such as benzene, toluene, xylene, ketones, alcohols, esters, ethers, and the like. It is interpreted as above.

Conventionally, a mixture of polyolefin and polyvinyl alcohol has been mainly used in the field using the hydrophilicity of polyvinyl alcohol rather than a multilayer structure product having barrier properties. The contents of this are as follows through related patents and patent application publications.

In U.S. Patent No. 4,529,539 and Japanese Patent No. 60147473, a mixture of polyolefin and polyvinyl alcohol was used in an electrically conductive plastic product. In Japanese Patent Nos. 77024976 and 54020057, a mixture of polyolefin and polyvinyl alcohol in a battery was used as a desiccant. Japanese Patent No. 70001747 was used to improve the dyeability of polyolefin fibers, and Japanese Patent No. 79036095 was used as a reinforcing fiber for cement to increase the strength of cement.

In addition, although there are a number of patents showing examples of using polyvinyl alcohol as a film to enable melting, each case has a different configuration from the present invention, the contents are as follows.

U.S. Patent No. 3,365,413 discloses an invention for use in blowing extrusion to lower the melting point of the resin by retaining the acetate content at 25 to 40 parts by weight during the polymerization of polyvinyl alcohol to act as a plasticizer.

U.S. Patent No. 3,997,489 discloses a method for improving melt processing properties by adding low molecular weight oils or waxes, and U.S. Patent No. 4,206,101 uses 5 to 20 parts by weight of polyethylene glycol to melt-extrude the water. A fast and completely soluble water soluble film is disclosed.

U.S. Patent No. 4,244,914 discloses a method of plasticizing polyvinyl alcohol with water and then removing water with an extruder vent while coextrusion in a liquid state, and U.S. Patent No. 4,611,019 adds polyvinylamide or polyester Disclosed is a melt extrusion process by plasticizing polyvinyl alcohol.

US Pat. No. 4,672,082 provides a method for enabling the production of polyvinyl alcohol in the absence of water, but has a problem of cooling at a sufficiently slow rate to improve barrier properties.

U.S. Patent No. 5,317,052 discloses the addition of a metal compound to polyvinyl alcohol to enable melting by raising the temperature of pyrolysis. European Patent No. 0 417 357 converts an extruder to provide sufficient energy for polyvinyl alcohol. The present invention provides a method for producing gel-free thermoplastic polyvinyl alcohol by melting polyvinyl alcohol at a high speed.

EP 0 187 040 discloses a process for preparing a film by preparing olefin / vinyl alcohol segment copolymers in which polyvinyl alcohol is introduced into polyethylene using silane, but using a plasticizer, a processing aid and an antioxidant, By using a very limited type of compatibilizer without improving vinyl alcohol, there is a problem that the oxygen barrier property is greatly reduced despite using the same amount of polyvinyl alcohol compared to the present invention. Since this allows only the blending of polyolefin and polyvinyl alcohol through modification by silane without improving the melting characteristics of polyvinyl alcohol, it does not have a morphology of the polyolefin and polyvinyl alcohol mixture resin of the present invention. There is a limit to the blocking ability of the.

European Patent No. 0 152 180 discloses a method of grafting polyvinyl alcohol by introducing a functional group into polyolefin, but mainly deals with the characteristics of the compatibilizer and the graft reaction accordingly, and gel generation, which is a fundamental problem in melt processing of polyvinyl alcohol. The problem of yellowing and yellowing is not solved.

Although polyvinyl alcohol is the polymer having the best gas and organic solvent barrier properties among the existing polymers, the melting point and the thermal decomposition temperature are close to each other, and the gel is easily generated. Particularly, since polyvinyl alcohol is very sensitive to heat, it is easily pyrolyzed even at a relatively low temperature, so that the gel increases, and yellowing phenomenon occurs severely, so it is very difficult to mold the product into a commercial product. Therefore, in the prior art, the polyvinyl alcohol was modified or added with a plasticizer to enable melting, but it did not completely solve the gel and yellowing phenomenon, which is a fundamental problem of polyvinyl alcohol. Although the molding method was used, the manufacturing cost of the film was greatly increased due to long drying.

In recent years, efforts have been made to utilize polyvinyl alcohol's excellent gas and organic solvent barrier properties by improving the reforming method and processing equipment through blending polyolefin and polyvinyl alcohol.

However, not all of these methods completely melt polyvinyl alcohol to enable molding processing freely, and the method using the excellent gas and organic solvent barrier properties of polyvinyl alcohol to the extent of having a commercial property is not much more.

Accordingly, an object of the present invention is to add a specific amount of a plasticizer, an initiator, a compatibilizer, a processing aid, and an antioxidant to a mixture of polyolefin and polyvinyl alcohol to enable melt molding by a conventional processing method and to form a unique morphology. It is to obtain films, sheets and shaped articles having high barrier properties to gases and organic solvents.

Another object of the present invention is to obtain a multilayer structure product having excellent gas and organic solvent barrier properties through the combination of the thus obtained films, sheets and shaped bodies with other resins.

1 is an electron microscope photograph of a 34 times larger cross section of a pellet,

FIG. 2 is an electron micrograph at 1500 times the cross section of the film.

The present invention,

(A) 1 to 80 parts by weight of polyolefin and 20 to 99 parts by weight of polyvinyl alcohol,

(B) 3 to 40 parts by weight of a polymeric compatibilizer, or 0.1 to 5 parts by weight of a low molecular weight compatibilizer and 0.01 to 0.5 parts by weight of an initiator which causes a reaction between the compatibilizer and a polyolefin based on 100 parts by weight of polyolefin, or the polymer Mixtures of compatibilizers with low molecular weight compatibilizers and initiators,

(C) 3 to 50 parts by weight of a plasticizer based on 100 parts by weight of polyvinyl alcohol,

(D) 1 to 10 parts by weight of the processing aid based on 100 parts by weight of polyvinyl alcohol, and

(E) relates to a film, a sheet, a molded article, and a multilayer structure product using the same by melting a mixed composition composed of 0.01 to 5 parts by weight of an antioxidant based on 100 parts by weight of polyvinyl alcohol.

Polyolefin has excellent processability and is cheaper than general-purpose resins and polyvinyl alcohol, which have different price, so it has superior advantages in price competition of final molded resin, while its barrier property to gas and organic solvents is inferior. In order to be used as a combination with a resin that can compensate for this is required. In the present invention, polyvinyl alcohol is selected as a material capable of ideally supplementing the disadvantages while maximizing the advantages of the polyolefin, thereby solving the mutual problem. Polyolefins used in the present invention include polyethylene (HDPE, LDPE, LLDPE, MDPE, VLDPE), polypropylene, polybutene, ethylene-propylene rubber (EP rubber), ethylene-propylene diene rubber (EPD rubber), poly-4- One or two or more polymers or copolymers selected from the group consisting of methyl-1-pentene (TPX), propylene, butene, hexene and / or octene and ethylene, and olefinic thermoplastic elastomers.

Polyvinyl alcohol is a polymer having excellent gas and organic solvent barrier properties among existing polymer resins, but the melting point and the pyrolysis temperature are close to each other, so that a conventional hot melt processing method cannot be applied. Polyvinyl alcohol may be used in various kinds, of which the degree of hydrolysis is 99.5 mol% or less, the degree of polymerization is preferably 300 to 3000, the degree of saponification is 85 to 90 mol% and the degree of polymerization 400 to It is more preferable that it is 2000.

The plasticizer lowers the melting point of the polyvinyl alcohol to enable thermal melting, lowers the crystallinity of the polyvinyl alcohol, and lowers rigidity and brittleness and solves the problem of gel formation. Plasticizers used in the present invention include glycerin, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, a mixture of glycerin and water, polyethylene glycol, polypropylene glycol, trimetholpropane, triethylene glycol, isopropanol There is one or more mixtures selected, and in particular, glycerin or a mixture of glycerin and water and trimetholpropane with a purity of at least 99% are preferred. As the content of the plasticizer increases, the processability of the polyvinyl alcohol is improved, but the barrier property is inferior. When the content is 5 parts by weight or less, the barrier property is very good, but the processability is significantly decreased, so it is more preferable that it is 5 to 30 parts by weight.

The polyvinyl alcohol starts to be thermally decomposed gradually from 100 ° C., and the decomposition rate increases more than 150 ° C., and then rapidly decomposes beyond 200 ° C., which can be observed from a phenomenon in which the color gradually changes to yellow. Therefore, a processing aid and an antioxidant to prevent yellowing of polyvinyl alcohol are required, and processing aids used in the present invention include acrylic oligomers, phosphates, calcium stearate, zinc stearate, magnesium stearate, One or more mixtures selected from the group consisting of stearic acid, paraffin wax, and polyethylene wax may be used, and the addition amount is more preferably 2 to 7 parts by weight based on 100 parts by weight of polyvinyl alcohol.

Antioxidants prevent yellowing and at the same time act as a stabilizer against heat during processing and / or prolonged use of polyvinyl alcohol. The antioxidant used in the present invention includes a phenolic antioxidant, a phosphate antioxidant, a calcium-zinc-tin organic mixture antioxidant, a dioctyltin malate-based antioxidant, and a dioctyltin-merhitide-based antioxidant. One or two or more mixtures selected from the group, and the amount is more preferably 0.05 to 3 parts by weight based on 100 parts by weight of polyvinyl alcohol.

Since polyolefins are inherently incompatible with polyvinyl alcohol, when mixed with resins, polyolefins form a separate interface, thereby preventing the molded products from properly exhibiting barrier properties and mechanical properties. Therefore, a polymer compatibilizer having a non-polar segment compatible with polyolefin and a polar segment compatible with polyvinyl alcohol simultaneously in one molecular unit, or by reacting and attaching to some molecular chains of polyolefin through the reaction, A low molecular weight compatibilizer for modifying the above and an initiator for inducing such a reaction are attached. In some cases, a high molecular compatibilizer, a low molecular compatibilizer and an initiator may be used together.

Polymeric compatibilizers include ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-alkyl acrylate-acrylic acid copolymer, ethylene-alkyl meta One or more mixtures selected from the group consisting of an acrylate-methacrylic acid copolymer, an ethylene-butylacrylate copolymer (EBA), an ethylene-vinylacetate copolymer (EVA), or a modified product thereof may be used, and Of these, maleic anhydride modified products of the ethylene-ethyl acrylate copolymer are particularly preferable. The addition amount is more preferably 5 to 20 parts by weight based on 100 parts by weight of the polyolefin.

As the low molecular system compatibilizer, monomers or unsaturated silane compounds having a carboxylic acid group in a molecular unit are used. For example, acrylic acid, methacrylic acid, maleic acid, fmaric acid, itaconic acid, crotonic acid, sorbic acid, or these Anhydrides of; Or vinyltrimethoxy silane, vinyltrimethoxymethoxyethoxy silane, vinyltriethoxy silane, gamma- (meth) acryloxypropyltrimethoxy silane, gamma- (meth) acryloxypropyltriethoxy silane, vinyl-tris One or more mixtures selected from the group consisting of (beta-methoxyethoxy) silane and vinyltriacetoxy silane are used. The addition amount of the low molecular weight compatibilizer is more preferably 0.5 to 3 parts by weight based on 100 parts by weight of the polyolefin.

As the initiator, one or more mixtures selected from the group consisting of acyl peroxide based, dialkyl or dialkyl peroxide based, peroxy ester based, hydroperoxide based, ketone peroxide based and azo compound based initiators are used, For example, benzoyl peroxide, di-tert-butyl peroxide, dicumyl peroxide, cumylbutyl peroxide, 1,1-di-tert-butylperoxy-3,5,5-trimethylcyclohexane, 2, 5-Methyl-2,5-2,5-di-tert-butyl peroxy isopropylbenzene, tert-butyl peroxy pivalate, tert-butyl di (perphthalate) dialkyl peroxy monocarbonate, pe One or two selected from the group consisting of oxydicarbonate, tertiary butyl hydroperoxide, p-methane hydroperoxide, cumene hydroxide, cyclohexano peroxide, methylethylketone peroxide, azobis isobutylonitrile Mixtures of the above may be used. The amount of the initiator added is more preferably 0.05 to 0.3 parts by weight based on 100 parts by weight of the polyolefin.

These polyolefin / polyvinyl alcohol mixed composition resins form a unique morphology, which is one of the features of the present invention.

The polyolefin / polyvinyl alcohol mixed composition resin may be classified into a case in which the polyvinyl alcohol content is 30 to 50 parts by weight and 50 to 70 parts by weight depending on the change in morphology. When the content of the polyvinyl alcohol is 30 to 50 parts by weight, the polyolefin forms a matrix phase, and when the content of the polyvinyl alcohol is 50 to 70 parts by weight, the polyvinyl alcohol forms a matrix phase.

When the polyolefin forms a matrix, that is, when the polyvinyl alcohol is 30 to 50 parts by weight, the polyvinyl alcohol forms a shape covered with the polyolefin, so that the property of dissolving the polyvinyl alcohol in water disappears. This shape can be confirmed in FIGS. 1 and 2 in which the mixed composition of polyolefin / polyvinyl alcohol is formed into pellets and films, respectively, and its cross section is taken by electron micrographs. Referring to FIG. 1 showing the cross section of the pellet, it can be seen that polyolefin (polyethylene) forms a circular matrix and polyvinyl alcohol forms several layers of continuous arc-shaped bands (“onion shapes”) in the matrix. . Looking at the cross section of the film, it can be seen that the outer polyolefin has a shape surrounding the polyvinyl alcohol of the middle face up and down. In FIG. 2, white projections can be observed in the middle of the film, which is a polyvinyl alcohol resin separated during the cutting of the film, in which a polyvinyl alcohol in the matrix of the polyolefin has a continuous plate shape ("plate"). Form ") to make sure it exists.

In particular, the morphology shown in the pellet is a very unique structure that does not appear in general pellet production, and in order to obtain such a continuous morphology, it is a structure obtained by forcibly biaxially stretching after forming into pellets and molding into a film or the like. The continuous onion-shaped structure appeared in the pellet is a structure that can maximize the barrier properties when forming into a film, sheet, container, etc., in particular, even in a thin film can significantly improve the barrier effect. In particular, with regard to the manufacture of films, conventional methods cannot use conventional molding machines and can only mold products through special modifications of the machine, but when using the composition pellets of the present invention, conventional processing without modification of the machine The film has excellent barrier property because of its excellent ability to form continuous plate-shaped morphologies even in the molding process.

As such, the resin of the mixed composition of the present invention exhibits a unique morphology not found in the resin of the conventional polyvinyl alcohol composition, and the morphology thereof maximizes the water resistance of the polyolefin while maximizing the gas and organic solvent barrier properties of the polyvinyl alcohol. It is a structure that can be expressed at the same time. In addition, the polyolefin forming the outer surface of the molded article can be hot melt adhesion without other adhesives with other polyolefin molded article and can form a molded article that is very stable to moisture in the air, so the barrier property of polyvinyl alcohol is not affected by the moisture at all. Do not. Therefore, the pellet of the polyolefin / polyvinyl alcohol mixed composition is extruded in a twin screw extruder, and then subjected to a long drying process such as polyamide or ethylene vinyl alcohol copolymer (EVOH), which is a conventional barrier material. It may be extruded directly without a single or co-extruded with other polyolefin and may be molded into a film, a sheet, a container or the like.

On the other hand, when the polyvinyl alcohol forms a matrix, that is, when the content of the polyvinyl alcohol is 50 to 70 parts by weight, the outer surface of the molding resin becomes a polyvinyl alcohol sensitive to moisture, and when used as a packaging multilayer structure product The adhesive should be used to coextrude or laminate with other polyolefin resins that are water resistant. The final molded article co-extruded or laminated with polyolefin has excellent barrier properties and can be manufactured by the same manufacturing method as conventional molding processes such as polyamide and EVOH, which are other barrier multilayer products. This barrier multilayer product is the same as other multilayer products in that it uses an adhesive, but the polyolefin / polyvinyl alcohol mixed composition resin is not only cheaper than polyamide, but also has much better barrier property, and has about 1 price of EVOH. It has the advantage of having a barrier of EVOH levels of only 3 levels. In addition, the existing polyamide has to be biaxially stretched the film to increase the barrier properties, there is a problem such as requiring a special extruder to make a biaxially stretched film.

An example of the process of making the mixture composition of the present invention into pellets before producing the film, sheet or other molded article is as follows.

First, a plasticizer, a processing aid and an antioxidant are added to polyvinyl alcohol and kneaded at 100 rpm or more in a super mixer or Hansel mixer for at least 5 minutes. The kneaded polyvinyl alcohol composition was dried at 80 to 120 ° C. for at least 3 hours. On the other hand, an initiator, a polymer compatibilizer and a low molecular weight use agent are added to the polyolefin and kneaded at 100 rpm or more in a super mixer or a Hancell mixer for 5 minutes. The separately kneaded polyvinyl alcohol composition and the polyolefin composition are kneaded again in a super mixer or one-cell mixer, extruded in a twin screw extruder, and then cut into pellets.

The film of the present invention may be obtained by first preparing in the form of pellets as described above and then melt processing or directly melting the mixed composition. The film of the present invention can be produced into a film by a general melt film forming method such as a blowing film forming method or a T-die melt molding method (or casting molding method). The resulting film can be used both in the stretched or unstretched state. In the blow molding method, biaxial stretching is possible directly by the tubular method. In the T-die melt molding method, the biaxial stretching is performed simultaneously or sequentially after the production of the unstretched film. Preferably, the polyolefin and polyvinyl alcohol mixed composition is made by a T-die melt molding method, and the film is biaxially stretched sequentially or simultaneously.

The content of vinyl alcohol units in the polyvinyl alcohol resin is an important variable for the barrier properties of oxygen and organic solvents. That is, the crystal structure is present as a monoclinic crystal structure only when the content (saponification degree) of the vinyl alcohol unit is 60 mol% or more to have a blocking effect. Polyvinyl alcohol is usually a crystalline polymer having a monoclinic structure because the degree of saponification is 85 mol% or more. However, the degree of crystallinity depends on the degree of saponification. For example, when the saponification degree of polyvinyl alcohol is 87 to 89 mol%, the crystallinity is 12 to 18%, and when the saponification degree is 98 to 99 mol%, the crystallinity is 30 to 40%. Therefore, the barrier property of polyvinyl alcohol with saponification degree of 98 to 99 mol% is more excellent. Unlike metals, polymers generally have low crystallinity, and many polymers contain a mixture of crystalline and amorphous portions. The polymer becomes amorphous (amorphous) by free thermal motion in the molten state, and as the temperature decreases, the molecular motion is relaxed to form a second crystal structure, and the degree of crystallinity varies depending on the processing conditions. Therefore, the degree of saponification and content of polyvinyl alcohol is also important for improving barrier properties, but in the same kind of polyvinyl alcohol, it is more important to increase the crystallinity. Stretching of the film plays an important role in increasing the degree of crystallinity, the greater the draw ratio, the higher the degree of crystallinity, preferably stretched to 3 or more.

When the polyolefin forms a matrix, the moisture permeability can be maintained at the level of the polyolefin, so that the film's barrier property can be easily hot melt adhered to the polyolefin without being affected by moisture, so that only the barrier effect can meet the commercially required level. If satisfied, the unit price of the product can be innovatively lowered with excellent physical properties. For example, in the case of a multilayer film made of polyethylene on both sides, conventionally, five layers of [polyethylene layer / adhesive layer / blocking layer / adhesive layer / polyethylene layer] were required, but according to the present invention, [polyethylene layer / blocking layer / Polyethylene layer] is required only two layers can be omitted, not only can reduce the number of manufacturing process, but also because the expensive adhesive is not used, there is a significant difference in cost. Conventional barrier layers are polyamide and EVOH, and the barrier layer of the present invention means a melt film layer of a polyolefin / polyvinyl alcohol mixed composition. In the case of using polypropylene instead of polyethylene in the above example, since the T-die melt molding method which can maximize the draw ratio which is important for increasing the crystallinity can be applied, biaxial stretching can be performed to maximize the blocking effect.

Therefore, preferably, a plasticizer, a processing aid, an antioxidant, a compatibilizer and an initiator are added to the mixture of 40 to 50 parts by weight of polyvinyl alcohol and 60 to 50 parts by weight of polypropylene to knead and knead these, and extruded in a twin screw extruder to pellet And extruded into a casting film by tee-die melt molding in a single extruder, and then stretched biaxially at the softening point of the film at 140 to 160 ° C. At this time, the greater the draw ratio, the greater the physical properties such as transparency, mechanical properties, barrier properties. After biaxial stretching, heat treatment at 80 to 140 ° C. for several minutes to several tens minutes yields a film that is more resistant to humidity, in which gas and organic solvent barrier properties do not change for a long time even at high humidity. The film thus produced shows superior barrier performance than the conventional barrier film biaxially stretched polyamide film, and may reach a level equivalent to the EVOH level depending on processing conditions. The increase in crystallinity and the improvement in blocking performance and general properties according to the draw ratio are also applied to the blown film.

When polyvinyl alcohol forms a matrix (when the content of polyvinyl alcohol is 50 to 70 parts by weight), polyvinyl alcohol is located on the outer surface of the molten film layer of the polyolefin / polyvinyl alcohol mixed composition, and polyvinyl alcohol As the water absorption rate of alcohol is very high, up to 20%, it is sensitive to moisture, and the direct contact with moisture in the air during extrusion greatly reduces gas and organic solvent barrier properties. The form of the multilayer film bonded to both surfaces is preferable. In order to bond the polyvinyl alcohol of the barrier layer and the polyolefin of the water resistant film layer, an adhesive material is used between the two, or a carboxylic acid group or a silane group is introduced directly into the polyolefin of the water resistant film layer, It is preferable to produce a multilayer film by coextrusion using a compatibilizer. Such multilayer films also have much the same gas and organic solvent barrier properties as EVOH, and are much more cost effective. On the other hand, the film produced by co-extrusion is proportional to the blocking performance of the film according to the draw ratio, the smaller the content of polyvinyl alcohol, the proportional relationship is apparent. When the content of polyvinyl alcohol exceeds 60 to 70 parts by weight, the blocking performance according to the draw ratio does not show a big difference, while the general physical properties still increase proportionally. Therefore, the draw ratio is preferably 3 X 3 to 5 X 5. This property also applies to both biaxial stretching and blow molding methods.

The present invention also relates to a multilayer film in which a film of another polymer is adhered to one or both sides of a molten film (“blocking layer”) of a polyolefin / polyvinyl alcohol mixed composition.

Examples of the material that adheres to one or both surfaces of the barrier layer include polyolefins, modified polymers or copolymers of polyolefins, or blending resins of polyolefins and other resins. The purpose of introducing other polymers on one or both sides of the barrier layer is to increase the price competitiveness for the same volume or weight by imparting new functionality or by adhering polymers with low resin costs.

When the polyolefin forms a matrix, as described above, in the conventional multilayer film, since the adhesion is possible by heat fusion without the necessary adhesive, the unit cost of the final product is greatly lowered. When the polyvinyl alcohol forms the matrix, the triple co-extrusion is preferable from the first time of manufacturing the barrier film as described above, and lamination may be added as necessary. Such molded products are mainly used for food and medicine, and also for industrial use.

To the multilayer film, a paper layer may be separately attached as necessary. The paper layer is located between the barrier layer and the other film layer, and a separate adhesive layer may be added if necessary. As an example, an adhesive is applied on the barrier layer of the two-layer film made by co-extrusion of the polyolefin / polyvinyl alcohol barrier layer and the polyolefin layer, and the paper layer is adhered by dry lamination and finally The polyethylene is melted and coated on a paper layer. In this case, since it is composed of five layers of [polyolefin layer / blocking layer / adhesive / paper layer / polyethylene layer], it is conventionally made of six layers of [polyolefin layer / adhesive / blocking layer / adhesive / paper layer / polyethylene layer]. Compared to the paper container multilayer film of the one layer has a structure that has the advantage that can shorten the work process. Such molded articles may be used as barrier paper containers such as milk, juices, alcoholic beverages (soju, sake, etc.).

The present invention also relates to a molded article in which the polyolefin / polyvinyl alcohol mixed composition is melt-molded in the form of a sheet or a container rather than in the form of a film. They may be a single melt of a polyolefin / polyvinyl alcohol mixed composition, and may be a multilayer sheet and a multilayer container in which resins composed of other components or polymers, etc., are continuous on one side, both sides or multilayer sides, as in the case of a multilayer film. In the case of sheets, the molding is produced by a triple or five coextrusion method and then commercialized into a container or a tray by thermoforming.

Since the molded article is produced by thermoforming as described above, polypropylene is preferable for the polyolefin of the barrier layer, and polypropylene is also preferable for the polymer introduced on both surfaces. On the other hand, polystyrene excellent in thermoforming can also be bonded to both surfaces of the barrier layer. When used for food, a barrier layer having a polyvinyl alcohol content of 50 parts by weight or more is preferable, a barrier layer of 60 to 70 parts by weight is more preferable, and five co-extrusion is preferable.

In the case of a container, it is manufactured by blow molding method, and when used for industrial use (pesticide container, paint container, fuel tank, organic solvent container, etc.), a barrier layer having a polyvinyl alcohol content of 30 to 50 parts by weight is preferable, and in particular, 40 to 50 More preferred is a barrier layer in parts by weight, and double coextrusion is preferred over barrier layer single extrusion or triple coextrusion or quadruple coextrusion.

Double co-extrusion of the barrier layer and HDPE reduces the cost of the product while eliminating the adhesive layer compared to the conventional HDPE / adhesive / blocking layer (polyamide or EVOH) triple coextrusion, and compared with the triple coextruder. Significantly lower prices for dual coextruders result in lower initial investment and lower floor composition, resulting in higher productivity. In the case of food and pharmaceutical containers, a barrier layer having a polyvinyl alcohol content of 50 parts by weight or more is preferable, particularly, a barrier layer of 60 to 70 parts by weight is more preferable, and a five-fold coextrusion is preferable.

When the polyolefin of the barrier layer and the polyolefin of the coating layer are each made of polypropylene, a packaging film, a sheet or a packaging container which can be used in boiling water or a microwave oven may be produced.

Hereinafter, the content of the present invention will be described in more detail with reference to Examples, but the content of the present invention is not limited by the following Examples.

Example 1

30 parts by weight of polyvinyl alcohol, 20 parts by weight of plasticizer, 2 parts by weight of processing aid, 0.05 parts by weight of antioxidant and super mixer (Super Mixer) based on 100 parts by weight of polyvinyl alcohol with different degrees of saponification and polymerization degree as shown in Table 1 below. 1 part by weight of a low molecular weight maleic anhydride and an initiator based on 100 parts by weight of LDPE based on 70 parts by weight of low density polyethylene (LDPE; melt index (MI) = 1, density (ρ) = 0.918) 0.1 parts by weight of indicumyl peroxide was coated on LDPE, which was dry blended with a mixture of the polyvinyl alcohol / plasticizer / processing aid / antioxidant in a supermixer. The mixture was dried in a drier at 80 ° C for 12 hours and then extruded in a twin screw extruder (Φ 40, Dae-Ae Co., Ltd.). At this time, the temperature gradient of the extruder is 170 ℃-190 ℃-200 ℃-210 ℃-220 ℃-200 ℃, the pellet was made by extruding at 40rpm and then made into a blown film of 600mm width and 45㎛ thickness in a single extruder . At this time, the temperature of the extruder was maintained at 220 to 230 ℃, a screw with a compression ratio of 3: 1 was used. Melting point, melting index, yellow index, haze and gas permeability of the resulting film were measured and shown in Table 1 below. The lower the values of yellow index, haze (transparency measurement) and gas permeability, the better the physical properties of the film.

Degree of safflower: mol%

AX-38: Phosphate Processing Aid (Hanong Adeka), Liquid, Viscosity 700cps

PEP-36: Phosphate Antioxidant (Hanong Adeka), White Powder, Melting Point (237 ℃), Molecular Weight (663)

Melt Index: Unit (g / 10min, 210 ℃)

Gas permeability: unit (cc / m ² , atm, 24 hours, 20 ° C, 65% RH)

phr: part per hundred raw material

Example 2

Polyvinyl alcohol (V1) having a degree of saponification of 99 mol% and a polymerization degree of 1,700, polyvinyl alcohol (V2) having a degree of polymerization of 88 mol% and a degree of polymerization of 1,700, and polyvinyl alcohol having a degree of polymerization of 88 mol% and a degree of polymerization of 600 (V3) was dry blended at different ratios to prepare a blown film in the same manner as in Example 1, and the melting point, melt index, yellow index, haze and gas permeability were measured.

Example 3

30 parts by weight of a polyvinyl alcohol mixture having a molecular weight of 99 mol% and a polyvinyl alcohol having a polymerization degree of 1,700 and a polyvinyl alcohol having a polymerization degree of 88 mol% and a polymerization degree of 600 at a weight ratio of 50 to 50 70 parts by weight of LDPE was dry blended in the same manner as in Example 1, and then cast using a Bravender plasti-coder single extruder while maintaining the temperature at 230 ° C. Was prepared. At this time, the gap of the T-die was fixed at 1 mm, the screw at 10 rpm, and the take-off speed at 0.8 m / min, respectively. The molecular weight change of LDPE is expressed as melt index (MI).

Example 4

Polyvinyl alcohol mixture of polyvinyl alcohol having a degree of saponification of 99 mol% and a polymerization degree of 1,700 and polyvinyl alcohol having a degree of polymerization of 88 mol% and a polymerization degree of 600 at a weight ratio of 50 to 50 and LDPE (MI = 1, ρ) = 0.918), the casting film was prepared in the same manner as in Example 3, and the yellow index, the haze, and the gas permeability were measured.

Example 5

To 30 parts by weight of polyvinyl alcohol having a degree of saponification of 88 and a polymerization degree of 600 and 70 parts by weight of LDPE, the type of plasticizer was changed, and 20 phr of a plasticizer, 20 phr of a processing aid, and 0.05 phr of an antioxidant were added in the same manner as in Example 1. To a pellet, and a casting film was prepared in the same manner as in Example 3 to measure yellow index, haze and gas permeability.

Example 6

A casting film was prepared in the same manner as in Example 5 while varying the amount of plasticizer glycerol added to 30 parts by weight of polyvinyl alcohol having a degree of saponification of 88 and a polymerization degree of 600 and 70 parts by weight of LDPE, and thus yellow index, haze and gas permeability. Was measured.

Example 7

Blown films were prepared in the same manner as in Example 1 by changing the type and amount of the processing aid and the antioxidant to 30 parts by weight of polyvinyl alcohol having a degree of saponification and a polymerization degree of 1,700 and 70 parts by weight of LDPE.

Example 8

Blown films were prepared in the same manner as in Example 1 by varying the type and amount of the compatibilizer with 30 parts by weight of polyvinyl alcohol having a degree of saponification of 88 mol% and a polymerization degree of 600 parts by weight of LDPE, and a yellow index and a haze. And gas permeability.

Example 9

Polyvinyl alcohol was prepared using a mixture containing polyvinyl alcohol having a degree of saponification of 88 mol% and a polymerization degree of 1,700 and polyvinyl alcohol having a degree of polymerization of 88 mol% and a degree of polymerization of 600 in a 50:50 weight ratio. The casting film was manufactured by the same method as 3, and yellow index, haze, and gas permeability were measured. The difference between the examples is that the casting film was molded by varying the extrusion temperature.

Example 10

Polyvinyl alcohol having a degree of saponification of 88 mol% and a polymerization degree of 600 was melt-extruded in an LDPE and a twin screw extruder in the same formulation as in Example 1, followed by LDPE (MI = 3, in a three-layer extruder). The yellow cast, haze and gas permeability were measured by molding a triple cast film coated on both sides with p = 0.918). At this time, the conditions of the triple extruder are the same as those of Example 3.

Example 11

Example 10 was repeated with 70 parts by weight of polyvinyl alcohol and 30 parts by weight of LDPE (MI = 1, p = 0.918). The difference from Example 10 is that 1 phr of low molecular compatibilizer and 0.1 phr of initiator dicumyl peroxide are coated on LDPE before co-extrusion of LDPE (MI = 3, ρ = 0.918) used to coat both sides. The reaction was carried out in a twin screw extruder to introduce carboxylic acid functional groups into the LDPE, and then extruded in triplicate to enable the adhesion of the LDPE / polyvinyl alcohol layer without the use of an adhesive.

Example 12

Examples 10 and 11 were repeated except that triple extrusion blown films were prepared. At this time, the extrusion conditions of the triple extrusion blower is the same as in Example 1.

Example 13

Examples 10 and 11 were repeated to prepare the casting film. The difference from Examples 10 and 11 is that LDPE (MI = 1, p = 0.918), which forms a mixed composition of the barrier layer, and LDPE resin (MI = 3, p = 0.918), which forms a coating layer, are PP (MI = 2, homopoly). Propylene) and PP resin (MI = 4, homo polypropylene). In the following # 42, VTMO was introduced into the PP (MI = 4, homopolypropylene) of the coating layer to facilitate extrusion with the PP / polyvinyl alcohol layer and triple extrusion.

Example 14

40 parts by weight of the polyvinyl alcohol content and 60 parts by weight of the PP content obtained in Example 13 were laminated in a press with a thickness of 1 mm, and then biaxially stretched in a 150 ° C. atmosphere to measure gas permeability.

Example 15

40 parts by weight of polyvinyl alcohol having a degree of saponification of 88 mol% and a polymerization degree of 600, and the same kind of plasticizer, processing aid, and antioxidant as in Example 1 were mixed, and were mixed with A-1600 (10 phr) and DCP (0.05 phr). 60 parts by weight of coated HDPE (MI = 0.3, p = 0.958) was dried in an 80 ° C. dryer for 12 hours and then extruded in a twin screw extruder to prepare pellets. In a double-layer blow molding extruder (Daechang Machinery Φ60, Φ35), HDPE (MI = 0.3, ρ = 0.958) was injected into the Φ60 extruder, and HDPE / polyvinyl alcohol was added to the Φ35 extruder, thereby forming a 500 ml container. The container has a thickness of 0.8 mm, an outer layer of HDPE of 0.72 mm and a barrier layer of inner layer HDPE / polyvinyl alcohol of 0.08 mm. The toluene is contained in this container and the inlet is sealed with aluminum and left for 2 weeks in an oven at 50 ° C., and then cycled for 3 weeks in a low temperature chamber at -10 ° C., followed by measuring the reduced weight with respect to the initial weight. % Loss was calculated. The weight loss was 0.3% and there was no change in container appearance.

As described above, the present invention, due to the unique morphology of the polyolefin / polyvinyl alcohol mixed composition resin, has a gas and organic solvent barrier properties, and also has a water resistance and can be melt processed in a conventional molding machine and low price As such, it provides an excellent barrier film comparable to expensive EVOH. In addition, when using such a film as part of a multi-layered product does not require a separate adhesive can reduce the number of manufacturing processes. On the other hand, the principle of the multi-layer film can be applied to a multi-layer sheet or a multi-layer container, it is possible to obtain excellent physical properties and cost reduction effect in the field requiring the barrier properties. Such a film, a multilayer film, a sheet, a container, etc. may be used in various fields such as packaging for food, pharmaceuticals, pesticides, or paint storage, fuel tanks or large-scale chemical storage of automobiles.

Claims (11)

(A) 1 to 80 parts by weight of polyolefin and 20 to 99 parts by weight of polyvinyl alcohol, (B) 3 to 40 parts by weight of a polymeric compatibilizer, or 0.1 to 5 parts by weight of a low molecular weight compatibilizer and 0.01 to 0.5 parts by weight of an initiator causing a reaction between the compatibilizer and a polyolefin, based on 100 parts by weight of polyolefin, or the polymer Mixtures of compatibilizers with low molecular weight compatibilizers and initiators, (C) glycerin, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, a mixture of glycerin and water, polyethylene glycol, polypropylene glycol, trimetholpropane, triethylene glycol, isopropanol based on 100 parts by weight of polyvinyl alcohol 3 to 50 parts by weight of one or more plasticizers selected from the group consisting of (D) one or more processing aids selected from the group consisting of acrylic oligomers, phosphates, calcium stearate, zinc stearate, magnesium stearate, stearic acid, paraffin wax, and polyethylene wax based on 100 parts by weight of polyvinyl alcohol 1 to 10 parts by weight, and (E) Screened phenolic antioxidant, phosphate antioxidant, calcium-zinc-tin organic mixture antioxidant, dioctyltin malate antioxidant, dioctyltin merpentide oxidation based on 100 parts by weight of polyvinyl alcohol A gas and organic solvent barrier film made by melting a mixed composition comprising 0.01 to 5 parts by weight of one or more antioxidants selected from the group consisting of inhibitors. The polymer compatibilizer according to claim 1, wherein the polymer compatibilizer is ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-ethylacrylate copolymer, ethylene-alkylacrylate-acrylic acid copolymer, ethylene-alkylmethacrylate-meth One or two or more mixtures selected from the group consisting of an acrylic acid copolymer, an ethylene-butyl acrylate copolymer, an ethylene-vinylacetate copolymer, or a modified product thereof, and a gas and organic solvent barrier film. The gas and organic solvent barrier film according to claim 2, wherein the polymer compatibilizer is a maleic anhydride modified product of the ethylene-ethyl acrylate copolymer. The method of claim 1, wherein the low molecular weight compatibilizer is acrylic acid, methacrylic acid, maleic acid, fmaric acid, itaconic acid, crotonic acid, sorbic acid, or anhydrides thereof; Or vinyltrimethoxysilane, vinyltrimethoxymethoxyethoxy silane, vinyltriethoxy silane, gamma- (meth) acryloxypropyltrimethoxy silane, gamma- (meth) acryloxypropyltriethoxy silane, vinyl-tris A gas and organic solvent barrier film that is one or more mixtures selected from the group consisting of (beta-methoxyethoxy) silane and vinyltriacetoxy silane. The method of claim 1, wherein the initiator is one or two selected from the group consisting of acyl peroxide-based, dialkyl or dialkyl peroxide-based, peroxy ester-based, hydroperoxide-based, ketone peroxide-based and azo compound-based initiators Gas and organic solvent barrier film which is a mixture of the above. The stretched film which biaxially stretched the film of Claim 1. Multilayer film comprising the barrier film of claim 1. The multilayer film according to claim 7, wherein the film is biaxially stretched. A multilayer paper film having a paper layer introduced on one or both sides of the stretched film of claim 6. A molded article having the same structure as the barrier film of claim 1. A multilayer molded body having the same structure as the multilayer film of claim 7.