JP2006045313A - Aqueous dispersion and aqueous heat-sealing agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous dispersion having good blocking resistance and heat-sealing property especially to a polyolefin material. <P>SOLUTION: The aqueous dispersion contains (A) 100 pts. mass of a polyolefin resin, (B) 5-90 pts. mass of a natural wax, and an aqueous medium. The polyolefin resin A is a copolymer composed of (A1) an unsaturated carboxylic acid unit, (A2) an ethylenic hydrocarbon and (A3) an acrylic acid ester or a methacrylic acid ester and the mass ratios of the components (A1) to (A3) satisfy the formulas (A1)/ä(A1)+(A2)+(A3)}=0.01/100 to 5/100 and (A2)/(A3)=55/45 to 95/5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an aqueous dispersion having good blocking resistance and excellent heat sealability, particularly excellent heat sealability for polyolefin materials.

  Polyolefin resins with a high copolymerization amount of ethylene and propylene components have good adhesion and heat sealability to various materials, such as heat sealants, delayed tack agents, fiber treatment agents, and binders for adhesives. It is used for a wide range of applications. Such a resin is used as an aqueous dispersion from the viewpoints of environmental protection, resource saving, workability and work environment.

  As an aqueous dispersion capable of forming a coating film excellent in adhesiveness and heat sealability, Patent Documents 1 and 2 disclose that a polyolefin resin having an unsaturated carboxylic acid content of less than 5% by mass is a non-volatile aqueous additive. Dispersed aqueous dispersions are disclosed without addition. Moreover, the aqueous dispersion which added the tackifying component of a specific composition as an aqueous dispersion with improved adhesiveness with respect to PP has been proposed (Patent Document 3).

  On the other hand, when a base material (film or sheet) such as a thermoplastic resin or aluminum, which is coated with an aqueous dispersion and has an adhesive layer on the surface, is further heat-sealed with another base material in a separate process, In many cases, the applied film or the like is wound up to form a roll. At this time, if the adhesive layer and the film superposed on the adhesive layer are blocked, the workability is remarkably lowered, which causes a problem.

  As a method for preventing blocking at the time of rolling as described above, it is known that a wax is added to an aqueous dispersion of a polyester-based graphft polymer (Patent Document 4).

  Patent Document 4 discloses an aqueous moisture-proof coating agent comprising an aqueous binder, wax, and polyolefin resin, and describes that blocking is improved by the addition of wax. However, there was no description or suggestion regarding the adhesiveness by such a coating agent, especially heat sealability.

JP 2003-119328 A JP 2003-103734 A JP 2004-051884 A Japanese Patent Laid-Open No. 11-348207 JP-A-10-53996

  The present inventors provide an aqueous dispersion that is water-based, has good anti-blocking properties, and has excellent heat-sealability, particularly excellent heat-seal properties for polyolefin materials. It is something to try.

  As a result of diligent research, the present inventors have found that by containing a specific proportion of a polyolefin resin and a specific wax in a specific ratio, it is possible to improve both the anti-blocking property and the heat sealing performance. The present invention has been reached.

That is, the gist of the present invention is as follows.
(1) The following polyolefin resin (A), natural wax (B), and aqueous medium are contained, and the mass ratio of the components (A) and (B) is 100 parts by mass of the solid content of the polyolefin resin (A). On the other hand, the aqueous dispersion is characterized in that the wax (B) is 5 to 90 parts by mass.

Polyolefin resin (A): a copolymer comprising an unsaturated carboxylic acid unit (A1), an ethylene-based hydrocarbon (A2), and an acrylic ester or methacrylic ester (A3), wherein (A1) to The mass ratio of the component (A3) is (A1) / {(A1) + (A2) + (A3)} = 0.01 / 100 to 5/100, (A2) / (A3) = 55/45 to 99 / Polyolefin resin that satisfies 1.
(2) An aqueous heat sealant containing the aqueous dispersion described in (1).
(3) A laminate obtained by laminating with an adhesive layer comprising the aqueous heat sealant according to (2).

  According to the aqueous dispersion of the present invention, it is possible to obtain a coating film and an adhesive layer which have good blocking resistance and excellent heat sealing properties which are contradictory properties. This film shows good adhesion even if it is thinly coated, and also has excellent heat sealability under wet heat conditions, especially between polyolefin materials and between polyolefin materials and different materials (for example, paper, aluminum, etc.) Suitable as a heat sealant. Moreover, since this invention can be provided as an aqueous dispersion, it is preferable also from aspects, such as environmental protection, resource saving, and fire fighting law.

Hereinafter, the present invention will be described in detail.

  The aqueous dispersion of the present invention contains the polyolefin resin (A) having a specific composition and the natural wax (B) in a specific ratio in an aqueous medium. Such a combination can improve the performance of both anti-blocking properties and heat-seal properties.

  The polyolefin resin (A) used in the present invention is a copolymer composed of an unsaturated carboxylic acid unit (A1), an ethylene hydrocarbon (A2), and an acrylic ester or methacrylic ester (A3). The mass ratio of the components (A1) to (A3) is (A1) / {(A1) + (A2) + (A3)} = 0.01 / 100 to 5/100, (A2) / (A3) = 55. / 45 to 99/1.

  The unsaturated carboxylic acid unit (A1) component must be (A1) / {(A1) + (A2) + (A3)} = 0.01 / 100 to 5/100, and this ratio is 0.1 / 100 to 5/100, more preferably 0.5 / 100 to 5/100, and most preferably 1/100 to 4/100. When the content of the component (A1) is less than 0.01% by mass, it becomes difficult to make the polyolefin resin (A) aqueous (liquefied), and it is difficult to obtain a good aqueous dispersion. On the other hand, when the content of the component (A1) exceeds 5% by mass, it becomes easy to make it aqueous, but the polarity of the resin is increased due to an increase in the amount of carboxyl groups, and the non-polar material such as PP Adhesiveness will decrease.

  The unsaturated carboxylic acid unit that can be used as the component (A1) is a compound having at least one carboxyl group or acid anhydride group in the molecule (in the monomer unit), specifically, acrylic acid, methacrylic acid, In addition to acids, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid, crotonic acid and the like, unsaturated dicarboxylic acid half esters, half amides and the like can be mentioned. Among these, acrylic acid, methacrylic acid, and (anhydrous) maleic acid are preferable, and acrylic acid and maleic anhydride are particularly preferable. Moreover, the unsaturated carboxylic acid should just be copolymerized in polyolefin resin, The form is not limited, For example, random copolymerization, block copolymerization, graft copolymerization etc. are mentioned.

  Ethylene hydrocarbon (A2) and acrylic acid ester or methacrylic acid ester (A3) component are 55/45 to 95/5 in mass parts (A2) / (A3) of component (A2) and component (A3). From the viewpoint of adhesiveness with PP, it is preferably 55/45 to 92/8, more preferably 60/40 to 90/10, and 65/35 to 87/13. Is more preferable, and 70/30 to 85/15 is particularly preferable. If the ratio of the component (A3) to {(A2) + (A3)} is less than 1 part by mass, the adhesiveness with PP and the heat sealability will be reduced, and it will be difficult to make the polyolefin resin water-based and good aqueous dispersion Getting a body becomes difficult. On the other hand, when the content of the compound (A3) exceeds 45 parts by mass, the properties as a polyolefin resin due to the component (A2) are lost, and performance such as adhesiveness to PP and heat sealability is deteriorated.

  Examples of the ethylene hydrocarbon (A2) component include alkenes having 2 to 6 carbon atoms such as ethylene, propylene, isobutylene, 2-butene, 1-butene, 1-pentene, 1-hexene, and a mixture thereof. May be. Among these, alkenes having 2 to 4 carbon atoms such as ethylene, propylene, isobutylene, and 1-butene are more preferable, ethylene and propylene are more preferable, and ethylene is particularly preferable.

  As the acrylic ester or methacrylic ester (A3) component, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, acrylic acid Examples include esterified products of acrylic acid or methacrylic acid such as hexyl, octyl acrylate, stearyl acrylate, and alcohols having 1 to 30 carbon atoms. Butyl acrylate is preferred, and methyl acrylate and ethyl acrylate are particularly preferred.

  As specific examples of the polyolefin resin (A), an ethylene-methyl acrylate-maleic anhydride copolymer or an ethylene-ethyl acrylate-maleic anhydride copolymer is most preferable. Here, the acrylic ester unit may be converted into an acrylic acid unit by hydrolyzing a small part of the ester bond when the resin is made into an aqueous solution described later. It suffices if the ratio of each constituent component taking into account the change is within a specified range.

  In addition, unsaturated carboxylic anhydride units such as maleic anhydride units form an acid anhydride structure in which adjacent carboxyl groups are dehydrated and cyclized in the dry state of the resin, but in particular an aqueous medium containing a basic compound Among them, a part or all of them are ring-opened, and it becomes easy to take a structure of carboxylic acid or a salt thereof.

  Further, in the polyolefin resin (A) used in the present invention, other monomers may be copolymerized at 20% by mass or less of the entire resin. Examples thereof include alkyl vinyl ethers having 3 to 30 carbon atoms such as methyl vinyl ether and ethyl vinyl ether, dienes, (meth) acrylonitrile, halogenated vinyls, halogenated vinylidenes, carbon monoxide, and sulfur dioxide.

  The polyolefin resin (A) preferably has a melt flow rate of 0.01 to 500 g / 10 minutes at 190 ° C. and 2160 g load, which is a measure of molecular weight, more preferably 0.1 to 400 g / 10 minutes, 300 g / 10 min is more preferable, and 5-200 g / 10 min is more preferable. If the melt flow rate of the polyolefin resin (A) is less than 0.01 g / 10 min, it becomes difficult to make the resin water-based, and it becomes difficult to obtain a good aqueous resin dispersion, or the heat sealability is lowered. . On the other hand, when the melt flow rate of the polyolefin resin (A) exceeds 500 g / 10 minutes, the resulting coating film tends to be hard and brittle, and the heat sealability tends to be lowered.

  As the natural wax (B) used in the present invention, plant wax such as candelilla wax, carnauba wax, rice wax, and wax, animal wax such as shellac wax and lanolin wax, mineral wax such as montan wax and ozokerite, Examples thereof include petroleum waxes such as paraffin wax and microcrystalline wax. Among these, candelilla wax, carnauba wax, and paraffin wax are preferable because they exhibit excellent heat sealability and blocking resistance, and candelilla wax and paraffin wax are particularly preferable.

  The aqueous dispersion of the present invention needs to contain the above-mentioned amounts of (A) and (B) at a predetermined ratio in order to satisfy all the performances such as blocking resistance and heat sealability of the coating film.

The content of the natural wax (B) needs to be 5 to 90 parts by mass with respect to 100 parts by mass of the polyolefin resin (A), and is preferably 5 to 80 parts by mass from the viewpoint of blocking resistance and adhesiveness. 5 to 60, more preferably 7 to 50 parts by weight, and particularly preferably 8 to 40 parts by weight. When the content of (B) is smaller than 5 parts by mass, the effect of improving the blocking resistance is small, and when it exceeds 90 parts by mass, the heat sealability tends to decrease.
In the present invention, it is not known in detail about the reason why the above-described polyolefin resin (A) and natural wax (B) are used in specific amounts to exhibit excellent adhesiveness, heat sealability and blocking resistance. However, it is estimated that it originates in moderate compatibility and a phase-separation structure.

  The aqueous medium in the present invention is most preferably all water from the viewpoint of safety to workers and the working environment. However, it is most preferable that all of it is water. However, in order to make the polyolefin resin (A) aqueous, the drying load is reduced. For this purpose, a hydrophilic organic solvent may be contained in addition to water as long as it does not depart from the characteristics of “aqueous”. Examples of such an organic solvent include ketones such as methyl ethyl ketone, acetone and diethyl ketone, alcohols such as phenol, butanol, methanol and ethanol, cyclic ethers such as tetrahydrofuran and dioxane, and ethylene glycol monobutyl ether. And glycol derivatives. The amount of these organic solvents in the total amount of the aqueous dispersion is preferably 40% by mass or less, more preferably 20% by mass or less, and further preferably 5% by mass or less. Further, the aqueous medium may contain a basic compound that is added when the polyolefin resin (A) is made aqueous as described later.

  The method for producing the aqueous dispersion of the present invention is particularly limited as long as the polyolefin resin (A) and the natural wax (B) are uniformly mixed in an aqueous medium and then dispersed or dissolved. However, there are two examples: (a) A method of mixing an aqueous dispersion of polyolefin resin (A) and an aqueous dispersion of natural wax (B), each prepared in advance; A method of simultaneously dispersing the polyolefin resin (A) and the natural wax (B) in water. Among these, the method (a) is preferable because an aqueous dispersion comprising a combination of various natural waxes and polyolefin resins can be prepared more easily.

First, the manufacturing method (a) of an aqueous dispersion is demonstrated.
When preparing an aqueous dispersion of a polyolefin resin (A), the number average particle diameter of the polyolefin resin particles in the aqueous dispersion is determined based on the stability of the aqueous dispersion, the surface smoothness when applied, and the natural wax (B). Is preferably 0.5 μm or less, more preferably 0.3 μm or less, even more preferably 0.2 μm or less from the viewpoint of transparency and performance (adhesiveness, heat sealability) of the coating film obtained by mixing with 0.15 μm or less is particularly preferable. Also about a weight average particle diameter, 0.5 micrometer or less is preferable and 0.3 micrometer or less is more preferable. By adopting a preparation method to be described later, the above particle diameter can be obtained.

  The method for obtaining the aqueous dispersion of polyolefin resin is not particularly limited. For example, a method of heating and stirring the polyolefin resin and the aqueous medium in a sealable container can be employed. At this time, the shape of the resin used for the aqueous treatment is not particularly limited, but it is preferable to use a granular or powdery one having a particle diameter of 1 cm or less, preferably 0.8 cm or less, from the viewpoint of increasing the aqueousization speed.

  Any container may be used as long as it is equipped with a tank into which liquid can be charged and can appropriately stir the mixture of the aqueous medium and resin charged into the tank. As such an apparatus, an apparatus widely known to those skilled in the art as a solid / liquid stirring apparatus or an emulsifier can be used, and an apparatus capable of pressurization of 0.1 MPa or more is preferably used. The stirring method and the rotation speed of stirring are not particularly limited.

  After each raw material is put into the tank of this apparatus, it is preferably stirred and mixed at a temperature of 40 ° C. or lower. Next, while maintaining the temperature in the tank at 50 to 200 ° C., preferably 60 to 200 ° C., the resin is sufficiently made aqueous by continuing stirring for 5 to 120 minutes, and then preferably 40 ° C. with stirring. An aqueous dispersion can be obtained by cooling to the following. When the temperature in the tank is less than 50 ° C., it becomes difficult to make the resin water-based. When the temperature in a tank exceeds 200 degreeC, there exists a possibility that the molecular weight of polyolefin resin may fall.

  At this time, it is preferable to add a basic compound in order to anionize the unsaturated carboxylic acid unit of the polyolefin resin (A). The addition amount of the basic compound is preferably 0.5 to 3.0 times equivalent to the carboxyl group in the polyolefin resin (1 mol of acid anhydride group is regarded as 2 mol of carboxyl group), 0.8 -2.5 times equivalent is more preferable and 1.0-2.0 times equivalent is especially preferable. If it is less than 0.5 times equivalent, the addition effect of a basic compound is not recognized, and if it exceeds 3.0 times equivalent, the drying time at the time of coating film formation may become long or the aqueous dispersion may be colored.

  As a basic compound added here, the compound which volatilizes at the time of coating-film formation is preferable from the surface of the water resistance of a coating film, and ammonia or various organic amine compounds are preferable. The boiling point of the organic amine compound is preferably 250 ° C. or lower. If it exceeds 250 ° C., it becomes difficult to scatter the organic amine compound from the resin coating film by drying, and the water resistance of the coating film may deteriorate. Specific examples of the organic amine compound include triethylamine, N, N-dimethylethanolamine, aminoethanolamine, N-methyl-N, N-diethanolamine, isopropylamine, iminobispropylamine, ethylamine, diethylamine, and 3-ethoxypropylamine. , 3-diethylaminopropylamine, sec-butylamine, propylamine, methylaminopropylamine, methyliminobispropylamine, 3-methoxypropylamine, monoethanolamine, diethanolamine, triethanolamine, morpholine, N-methylmorpholine, N- Examples thereof include ethyl morpholine.

  Moreover, it is preferable to add an organic solvent when making the polyolefin resin (A) aqueous. The addition amount of the organic solvent is preferably 1 to 40 parts by mass, more preferably 2 to 30 parts by mass, and particularly preferably 3 to 20 parts by mass with respect to 100 parts by mass of the aqueous polyolefin resin dispersion. The organic solvent can be removed (stripped) partly from the system by heating the aqueous dispersion with stirring under normal pressure or reduced pressure. It can also be 1 mass part or less with respect to 100 mass parts of dispersions. Specific examples of the organic solvent used include ethanol, n-propanol, isopropanol, n-butanol, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, and ethylene glycol monobutyl ether. From the viewpoint of drying at a lower temperature, ethanol, isopropanol, and n-propanol are particularly preferable.

  By making the polyolefin resin (A) aqueous by the above method, a fine and stable aqueous dispersion can be obtained without adding a non-volatile aqueous additive such as an emulsifier. Those having excellent adhesiveness and heat sealability can be produced.

  The aqueous dispersion of natural wax (B) may be produced by a method according to the above-described method for preparing the aqueous dispersion of polyolefin resin (A), but a commercially available aqueous dispersion may be used. Examples of commercially available wax aqueous dispersions include, for example, paraffin wax aqueous dispersions EMUSTAR-1015, 1115, 0135, 0136, 1055, 1155, 1070, 1170 manufactured by Nippon Seiki Co., Ltd., microcrystalline wax aqueous dispersions EMUSTAR-1045, 1145, 0001, 042X, carnauba wax aqueous dispersion EMUSTAR-0413, and the like.

  Next, each aqueous dispersion of the obtained polyolefin resin (A) and natural wax (B) is mixed. In mixing, a known liquid / liquid mixing apparatus may be used as appropriate. Since the dispersion and mixing properties of the aqueous polyolefin resin dispersion and the aqueous natural wax dispersion are good, a simple mixing operation is possible for a very short time. Further, after mixing, the solid content concentration can be adjusted by the same method as described above.

  As the method (a) for producing the aqueous dispersion of the present invention, for example, the above-mentioned method of heating and stirring a polyolefin resin and natural wax, a basic compound, and an aqueous medium in a container can be employed. It is charged into the apparatus, and then heated (for example, 45 to 200 ° C.) to sufficiently disperse the polyolefin resin and the natural wax by continuing stirring until coarse particles disappear (for example, 5 to 120 minutes), and then stirred. An aqueous heat sealant can be obtained by cooling to 40 ° C. or lower. Moreover, solid content concentration can be adjusted similarly to a manufacturing method (a).

  The aqueous dispersion of the present invention can form a coating film by removing the liquid medium after coating on various substrates. The coating film has excellent blocking resistance, and also has excellent adhesion and heat sealability to various materials, so various coating agents, primers, adhesives, heat sealants, paints and inks can be used. It can be used as a binder and is particularly suitable as a heat sealant.

  Usable base materials can be used for coating or impregnation on paper, synthetic paper, thermoplastic resin film, plastic products, steel plate, aluminum foil, wood, woven fabric, knitted fabric, non-woven fabric, gypsum board, wood board, etc. . Especially, it is preferable to use for paper, a synthetic paper, and a thermoplastic resin film.

  Examples of thermoplastic resin films include polyester resins such as PET, polyethylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, and polyhydroxycarboxylic acids such as polyglycolic acid and polylactic acid. Biodegradable resins typified by aliphatic polyester resins such as poly (ethylene succinate) and poly (butylene succinate), polyamide resins such as nylon 6, nylon 66, nylon 46, PP, polyethylene, ethylene-vinyl Examples thereof include films made of thermoplastic resins such as polyolefin resins such as acetate copolymers, polyimide resins, polyarylate resins, or mixtures thereof, and laminates thereof. Among these, polyesters, polyamides, polyethylenes, etc. Emissions, ethylene - vinyl acetate copolymer, consisting of PP film can be suitably used. These base films may be unstretched films or stretched films, and the production method is not limited. Moreover, although the thickness of a base film is not specifically limited, Usually, what is necessary is just to be the range of 1-500 micrometers. Furthermore, you may perform what is called in-line coating which apply | coats the aqueous dispersion of this invention to an unstretched film, and extends | stretches the coat film.

  The method of applying the aqueous dispersion of the present invention to a substrate is not particularly limited, but gravure roll coating, reverse roll coating, wire bar coating, lip coating, air knife coating, curtain flow coating, spray coating, dipping Coating, brushing, etc. can be employed. What is necessary is just to determine suitably the application quantity of an aqueous dispersion with a base material. In the case where the substrate is a thermoplastic resin film, the thickness of the coating film is preferably at least 0.1 μm, more preferably 0.1 to 10 μm, in order to sufficiently enhance the heat sealability. 2-8 micrometers is further more preferable and 0.3-7 micrometers is especially preferable.

  The drying temperature of the aqueous dispersion of the present invention is not particularly limited and may be appropriately determined depending on the heat-resistant temperature of the base material, etc., but is usually 50 to 240 ° C., more preferably 60 to 210 ° C., 70-200 degreeC is further more preferable. When the drying temperature is less than 50 ° C., the aqueous medium cannot be volatilized sufficiently, or it takes time to volatilize, and it becomes difficult to develop good adhesive performance. On the other hand, when the drying temperature exceeds 240 ° C., the adhesion performance tends to decrease.

  In addition, a material (thermoplastic film, paper, synthetic paper, aluminum foil, etc.) in which a coating film obtained from the aqueous dispersion of the present invention is laminated is excellent in heat sealability. A base material can be laminated | stacked and it can be set as a laminated body. As a base material that can be combined, a thermoplastic resin film, paper, synthetic paper, wood, woven fabric, knitted fabric, non-woven fabric, etc., as well as the above-described base materials, metal foils such as aluminum, etc. are appropriately selected and used. Can be the same or different. Among them, at least one is preferably a polyolefin resin material such as PP, and is used for lamination of polyolefin resin materials, lamination of polyolefin resin material and paper or synthetic paper, and lamination of polyolefin resin material and aluminum foil. Further preferred.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

Various characteristics were measured or evaluated by the following methods.
(1) Structure of polyolefin resin ¹ H-NMR analysis (manufactured by Varian, 300 MHz) was performed at 120 ° C. in orthodichlorobenzene (d ₄ ).
(2) Melt flow rate of polyolefin resin This is a value measured by the method described in JIS 6730 (190 ° C., 2160 g load).
(3) Melting | fusing point of polyolefin resin It is the value measured at the temperature increase rate of 10 degree-C / min using DSC (DSC-7 by Perkin Elmer).
(4) Solid content concentration of aqueous polyolefin resin dispersion An appropriate amount of the aqueous polyolefin resin dispersion was weighed and heated at 150 ° C. until the mass of the residue (solid content) reached a constant weight to determine the solid content concentration.
(5) Average particle diameter of polyolefin resin particles A number average particle diameter and a weight average particle diameter were determined using a Microtrac particle size distribution analyzer UPA150 (MODEL No. 9340) manufactured by Nikkiso Co., Ltd.

  In the following evaluations (6) to (10), the coated substrate was allowed to stand at room temperature for 1 day, and then subjected to various evaluation tests.

(6) Water resistance evaluation The coating film was rubbed 10 times with a cloth wetted with water, and the state of the coating film was visually evaluated.
○: No change △: The coating film is cloudy ×: The coating film is completely dissolved

(7) Evaluation of blocking resistance The aqueous dispersion of the present invention was coated on an aluminum foil (manufactured by Mitsubishi Aluminum Co., Ltd.) with a Mayer bar so that the coating amount after drying was about 5 g / m ² , and at 90 ° C. for 120 seconds. Dried. With the aluminum foil superimposed on the coated surface, a load of 0.1 MPa was applied, and after standing for 24 hours in an atmosphere of 30 ° C. and 65% RH, the blocking resistance was evaluated in the following three stages.
○: The aluminum foil is peeled off by gently lifting it.
(Triangle | delta): It peels by pulling aluminum foil.
X: The aluminum foil is broken, or the interface or cohesive peeling of the coating film is observed.

(8) Tape peeling evaluation (adhesion evaluation)
An aqueous dispersion is made of a stretched polypropylene (PP) film (thickness 50 μm), a biaxially stretched polyethylene terephthalate (PET) film (Embret PET12 made by Unitika, thickness 12 μm), a biaxially stretched nylon 6 (Ny6) film (emblem made by Unitika) And coated with a Mayer bar so that the coating amount after drying is about 2 g / m ² on a non-treated surface having a thickness of 15 μm), dried at 100 ° C. for 2 minutes, and then coated with adhesive tape (manufactured by Nichiban Co., Ltd.). After attaching TF-12), the tape was peeled off vigorously. The state of the coating film surface was visually observed and evaluated as follows.
○: No peeling at all.
Δ: Some peeling occurred.
X: All peeled off.

(9) Heat seal strength evaluation A coating liquid containing an aqueous dispersion is coated on a corona-treated surface of a stretched polypropylene (PP) film (thickness 50 μm) and an aluminum foil (Mitsubishi Aluminum Co., Ltd., thickness 15 μm). The film was coated with a Mayer bar so as to be about 4 g / m ² and dried at 90 ° C. for 120 seconds. When coated on PP film, coated surfaces are coated with aluminum foil. When coated with aluminum foil, the coated surface and the corona surface of the PP film are in contact with each other, and a heat press machine (sealing pressure of 3 kg / cm ² for 5 seconds) is used. And pressed at 120 ° C. This sample was cut out at a width of 15 mm, and one day later, using a tensile tester (precision universal material tester type 2020 manufactured by Intesco), the peel strength of the coating film was measured at a pulling speed of 200 mm / min and a pulling angle of 180 degrees. The heat seal strength was evaluated.

(10) Heat seal strength evaluation after wet heat treatment After drying the coating liquid containing the aqueous dispersion on the corona-treated surface of stretched polypropylene (PP) film (thickness 50 μm) and aluminum foil (Mitsubishi Aluminum Co., Ltd., thickness 15 μm). The coating amount was about 4 g / m ² with a Mayer bar and dried at 90 ° C. for 120 seconds. When coated on PP film, coated surfaces are coated with aluminum foil. When coated with aluminum foil, the coated surface and the corona surface of the PP film are in contact with each other, and a heat press machine (sealing pressure of 3 kg / cm ² for 5 seconds) is used. And pressed at 120 ° C. This sample was cut out with a width of 15 mm, wet-heat treated at 40 ° C. and 90% RH for 7 days, and then pulled using a tensile testing machine (precision universal material testing machine 2020 manufactured by Intesco) at a pulling speed of 200 mm / min. The heat seal strength was evaluated by measuring the peel strength of the coating film at an angle of 180 degrees.

  Table 1 shows the composition of the polyolefin resin used in the present invention.

(Production of aqueous polyolefin resin dispersion E-1)
Using a stirrer equipped with a hermetic pressure-resistant 1 L glass container with a heater, 125.0 g of polyolefin resin [Bondaine HX-8290 (A), manufactured by Atofina Japan Co., Ltd.], 75.0 g of isopropanol (hereinafter, IPA) 7.0 g of triethylamine (hereinafter referred to as TEA) and 293 g of distilled water were charged into a glass container and stirred at a rotation speed of the stirring blade of 300 rpm. It was confirmed that it was in a state. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the system temperature was kept at 130 ° C. and further stirred for 30 minutes. Then, after cooling to room temperature (about 25 ° C.) while stirring with air rotation at 300 rpm, pressure filtration (air pressure 0.2 MPa) with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave) As a result, a milky white uniform polyolefin resin aqueous dispersion E-1 was obtained. Various characteristics of this aqueous dispersion are shown in Table 2.

(Production of aqueous polyolefin resin dispersion E-2)
Using a stirrer equipped with a hermetic pressure-resistant 1 L glass container with a heater, 100.0 g polyolefin resin [Bondaine TX-8030 (I), manufactured by Atofina Japan Co., Ltd.], 150.0 g IPA, 6.0 g When TEA and 244.0 g of distilled water were charged into a glass container and stirred at a rotating speed of the stirring blade of 300 rpm, it was confirmed that no sedimentation of resin particles was observed at the bottom of the container and that it was in a floating state. It was done. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the system temperature was kept at 130 ° C. and further stirred for 30 minutes. Then, after cooling to room temperature (about 25 ° C.) while stirring with air rotation at 300 rpm, pressure filtration (air pressure 0.2 MPa) with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave) As a result, a milky white uniform polyolefin resin aqueous dispersion E-2 was obtained. Various characteristics of this aqueous dispersion are shown in Table 2.

(Production of aqueous polyolefin resin dispersion E-3)
A polyolefin resin aqueous dispersion E-3 was obtained in the same manner as in E-1, except that a polyolefin resin [Bondaine HX-8210 (U), manufactured by Atofina Japan Co., Ltd.] was used. Various characteristics of this aqueous dispersion are shown in Table 2.

(Production of aqueous polyolefin resin dispersion E-4)
Primacol 5980I (D) (manufactured by Dow Chemical Company) was used as the polyolefin resin. Using a stirrer equipped with a 1 L glass container that can be sealed with a heater, 60.0 g of Primacol 5980I, 16.8 g of TEA, and 223.2 g of distilled water were charged into the glass container, When stirring was performed at a rotation speed of 300 rpm, no precipitation of resin particles was observed at the bottom of the container, and it was confirmed that the container was in a floating state. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the system temperature was kept at 130 ° C. and further stirred for 30 minutes. Then, after cooling to room temperature (about 25 ° C.) while stirring with air rotation at 300 rpm, pressure filtration (air pressure 0.2 MPa) with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave) As a result, a slightly white aqueous dispersion E-4 was obtained. Various characteristics of this aqueous dispersion are shown in Table 2.

(Preparation of candelilla wax dispersion W-1)
40.0 g of Candelilla wax (manufactured by Toa Kasei Co., Ltd., acid value: 15.8, saponification value: 55.4), 8 When 8 g of morpholine (manufactured by Nacalai Tesque) and 151.2 g of distilled water were charged into a glass container and stirred at a rotation speed of the stirring blade of 400 rpm, no resin precipitation was observed at the bottom of the container. It was confirmed that it was in a state. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the system temperature was kept at 100 ° C. and further stirred for 10 minutes. Then, after cooling to room temperature (about 25 degreeC), stirring by air cooling with a rotational speed of 600 rpm, the pale yellow uniform wax aqueous dispersion W-1 was obtained. The solid content concentration was 20.0% by mass, and the number average particle size was 0.27 μm.

Example 1
Aqueous polyolefin resin dispersion E-1 and aqueous paraffin wax dispersion (EMUSTAR-0135, manufactured by Nippon Seiki Co., Ltd.) (hereinafter referred to as 0135) so that the wax is 20 parts by mass with respect to 100 parts by mass of polyolefin resin. Was mixed and stirred to prepare an aqueous dispersion T-1. Table 3 shows the performance evaluation results of the coating film using this.

Examples 2-4
As shown in Table 3, the amount of 0135 added was 40 parts by mass (Example 2), 80 parts by mass (Example 3), and 10 parts by mass (Example 4). Dispersions T-2-4 were prepared. Table 3 shows the performance evaluation results of the coating film using this.

Examples 5 and 6
Aqueous dispersions T-5 and 6 were prepared in the same manner as in Example 1, except that the polyolefin resin aqueous dispersions E-2 (Example 5) and E-3 (Example 6) were used. Table 3 shows the performance evaluation results of the coating film using this.

Example 7
An aqueous dispersion T-7 was prepared in the same manner as in Example 1 except that the candelilla wax aqueous dispersion W-1 was used. Table 3 shows the performance evaluation results of the coating film using this.

Example 8
An aqueous dispersion T-8 was prepared in the same manner as in Example 1 except that carnauba wax aqueous dispersion (Nippon Seiki Co., Ltd., EMUSTAR-0413) (hereinafter referred to as 0413) was used. Table 3 shows the performance evaluation results of the coating film using this.

Comparative Examples 1-3
A polyolefin resin aqueous dispersion E-1 to E3 (here, H-1 to 3) was used without adding the natural wax (B). Table 4 shows the results of performance evaluation of the coating film using this.

Comparative Example 4
As shown in Table 3, an aqueous dispersion H-4 was prepared in the same manner as in Example 1, except that the addition amount of 0135 was 100 parts by mass. Table 4 shows the results of performance evaluation of the coating film using this.

Comparative Example 5
An aqueous dispersion H-5 was prepared in the same manner as in Example 1 except that an aqueous dispersion of polyethylene wax, which is a synthetic wax, (EMUSTAR-0443, manufactured by Nippon Seiki Co., Ltd.) (hereinafter 0443) was used instead of natural wax. Prepared. Table 4 shows the results of performance evaluation of the coating film using this.

Comparative Example 6
Example 1 except that a tackifier (manufactured by Yashara Chemical Co., Ltd., Nanolet R-1050, resin concentration 50%, average particle size 0.3 μm, softening point 105 ° C.) (hereinafter R-1050) was used instead of natural wax. An aqueous dispersion H-6 was prepared in the same manner as described above. Table 4 shows the results of performance evaluation of the coating film using this.

Comparative Example 7
Aqueous dispersion H-7 was prepared in the same manner as in Example 1, except that Primmacor 8980I aqueous dispersion E-4 was used as the aqueous polyolefin resin dispersion. Table 4 shows the results of performance evaluation of the coating film using this.

  In Examples 1-8, it was excellent in heat-sealability and blocking resistance irrespective of the kind of base film. Furthermore, the performance did not deteriorate even after the wet heat treatment. When the addition amount of the wax is small, a tendency to add blocking resistance is recognized (Example 4), and when the addition amount of the wax is large, a tendency to decrease the heat sealability is recognized (Example 3). There was no level. Regarding the composition of the polyolefin resin, it was found that the content of the acrylate greatly affects the adhesiveness and heat sealability (Examples 1, 5 and 6). Moreover, if it was a natural wax, the favorable performance was recognized even if it changed the kind. (Examples 1, 7, and 8).

On the other hand, Comparative Examples 1 to 3 had a problem in blocking resistance because natural wax was not blended. Moreover, since the addition amount of the natural wax was outside the scope of the present invention in Comparative Example 4, although the blocking resistance was good, the heat sealability was inferior. In Comparative Example 5, since a wax outside the scope of the present invention was used, the heat sealability tended to decrease. In Comparative Example 6, since a tackifier was added instead of wax, no improvement in blocking was observed. In Comparative Example 7, since a resin outside the scope of the present invention was used as the polyolefin resin, adhesiveness and heat sealability were hardly exhibited.

Claims (3)

An aqueous dispersion containing 100 parts by mass of the following polyolefin resin (A), 5 to 90 parts by mass of natural wax (B), and an aqueous medium.
Polyolefin resin (A): a copolymer comprising an unsaturated carboxylic acid unit (A1), an ethylene-based hydrocarbon (A2), and an acrylic ester or methacrylic ester (A3), wherein (A1) to The mass ratio of the component (A3) is (A1) / {(A1) + (A2) + (A3)} = 0.01 / 100-5 / 100, (A2) / (A3) = 55 / 45-95 / Polyolefin resin satisfying 5. An aqueous heat sealant containing the aqueous dispersion according to claim 1. The laminated body laminated | stacked by the contact bonding layer which consists of the water-based heat-sealing agent of Claim 2.