Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
  • B05D7/24—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials for applying particular liquids or other fluent materials
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/04—Homopolymers or copolymers of ethene
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J123/00—Adhesives based on homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Adhesives based on derivatives of such polymers
  • C09J123/02—Adhesives based on homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Adhesives based on derivatives of such polymers not modified by chemical after-treatment
  • C09J123/04—Homopolymers or copolymers of ethene
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
  • C09J7/38—Pressure-sensitive adhesives [PSA]

Definitions

• the present invention relates to an aqueous dispersion and a laminate.
• heat sealing it is conventionally known in various industrial fields to bond substrates such as plastic films, vapor-deposited films, metal foils, paper, and nonwoven fabrics together by heat and pressure (i.e., heat sealing).
• heat sealing an adhesive layer is usually formed on the substrate in advance, and the substrates are bonded together or to other adherends via the adhesive layer.
• a water dispersion containing a resin is known as a material used for the adhesive layer.
• a water dispersion containing water, resin A (ethylene-acrylic acid copolymer (acrylic acid content 20.5% by mass)), resin B (ethylene-methacrylic acid copolymer (methacrylic acid content 15% by mass)), and resin C (ethylene-methacrylic acid copolymer (methacrylic acid content 10% by mass)) has been proposed as such a water dispersion (see, for example, water dispersion 2 in Patent Document 1).
• aqueous dispersions require even greater storage stability.
• the present invention aims to provide an aqueous dispersion with excellent storage stability, and a laminate having an adhesive layer that is a dried product of the aqueous dispersion.
• the present invention [1] is an aqueous dispersion comprising a resin component and water, the resin component comprising an ethylene-unsaturated carboxylic acid copolymer, the ethylene-unsaturated carboxylic acid copolymer comprising a first ethylene-unsaturated carboxylic acid copolymer, a second ethylene-unsaturated carboxylic acid copolymer, and a third ethylene-unsaturated carboxylic acid copolymer, each of which has a different carboxyl group content, the difference (C-B) between the carboxyl group content C of the third ethylene-unsaturated carboxylic acid copolymer and the carboxyl group content B of the second ethylene-unsaturated carboxylic acid copolymer being greater than 0 mmol/kg and not greater than 0.50 mmol/kg, and the difference (B-A) between the carboxyl group content B of the second ethylene-unsaturated carboxylic acid copolymer and the carboxy
• the present invention [2] includes the aqueous dispersion described in [1] above, in which the carboxyl group content A of the first ethylene-unsaturated carboxylic acid copolymer is 1.00 mmol/kg or more and less than 1.40 mmol/kg, the carboxyl group content B of the second ethylene-unsaturated carboxylic acid copolymer is 1.40 mmol/kg or more and less than 1.80 mmol/kg, and the carboxyl group content C of the third ethylene-unsaturated carboxylic acid copolymer is 1.80 mmol/kg or more and less than 2.30 mmol/kg.
• the present invention [3] includes the aqueous dispersion according to the above [1] or [2], in which the content of the first ethylene-unsaturated carboxylic acid copolymer is 30 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the total amount of the first ethylene-unsaturated carboxylic acid copolymer, the second ethylene-unsaturated carboxylic acid copolymer, and the third ethylene-unsaturated carboxylic acid copolymer, the content of the second ethylene-unsaturated carboxylic acid copolymer is 5 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the total amount of the first ethylene-unsaturated carboxylic acid copolymer, the second ethylene-unsaturated carboxylic acid copolymer, and the third ethylene-unsaturated carboxylic acid copolymer, and the content of the third ethylene-unsaturated carboxylic acid copolymer is 30 parts
• the present invention [4] includes the aqueous dispersion according to any one of [1] to [3] above, in which the content of the third ethylene-unsaturated carboxylic acid copolymer is greater than or equal to the content of the first ethylene-unsaturated carboxylic acid copolymer, and the content of the first ethylene-unsaturated carboxylic acid copolymer is greater than the content of the second ethylene-unsaturated carboxylic acid copolymer.
• the present invention [5] includes the aqueous dispersion according to any one of [1] to [4] above, in which the first ethylene-unsaturated carboxylic acid copolymer is a copolymer of ethylene and methacrylic acid, the second ethylene-unsaturated carboxylic acid copolymer is a copolymer of ethylene and methacrylic acid, and the third ethylene-unsaturated carboxylic acid copolymer is a copolymer of ethylene and acrylic acid.
• the present invention [6] includes a laminate having a substrate and an adhesive layer in order toward one side in the thickness direction, the adhesive layer being a dried product of the aqueous dispersion described in any one of [1] to [5] above.
• the ethylene-unsaturated carboxylic acid copolymer includes a first ethylene-unsaturated carboxylic acid copolymer, a second ethylene-unsaturated carboxylic acid copolymer, and a third ethylene-unsaturated carboxylic acid copolymer, each of which has a different carboxyl group content.
• the difference (C-B) between the carboxyl group content C of the third ethylene-unsaturated carboxylic acid copolymer and the carboxyl group content B of the second ethylene-unsaturated carboxylic acid copolymer, and the difference (B-A) between the carboxyl group content B of the second ethylene-unsaturated carboxylic acid copolymer and the carboxyl group content A of the first ethylene-unsaturated carboxylic acid copolymer are within a specified range. Therefore, the storage stability is excellent.
• the laminate of the present invention has an adhesive layer that is a dried product of the aqueous dispersion of the present invention. Therefore, it has excellent productivity.
• FIG. 1 is a schematic diagram showing one embodiment of a laminate of the present invention.
• 2A to 2C are schematic diagrams showing one embodiment of a method for producing a laminate of the present invention, and a method for bonding substrates together using this laminate.
• Fig. 2A shows a first step of preparing a first substrate.
• Fig. 2B shows a second step of disposing an adhesive layer on one thickness-wise surface of the first substrate.
• Fig. 2C shows a step of disposing a second substrate on one thickness-wise surface of the adhesive layer, and bonding the first substrate and the second substrate by thermocompression bonding.
• 3A and 3B show a modified example of the method for producing a laminate of the present invention.
• FIG. 3A shows a step of disposing an adhesive layer on each of a first substrate and a second substrate.
• Fig. 3B shows a step of bonding the first substrate and the second substrate together via the adhesive layer.
• FIG. 4 shows a schematic diagram of an ethylene-unsaturated carboxylic acid copolymer in an aqueous dispersion.
• the aqueous dispersion contains a resin component and water.
• the resin component includes an ethylene-unsaturated carboxylic acid copolymer.
• the ethylene-unsaturated carboxylic acid copolymer includes a first ethylene-unsaturated carboxylic acid copolymer, a second ethylene-unsaturated carboxylic acid copolymer, and a third ethylene-unsaturated carboxylic acid copolymer, each of which has a different carboxyl group content.
• the first ethylene-unsaturated carboxylic acid copolymer which will be described in detail later, is a resin having a relatively low carboxyl group content compared to the second ethylene-unsaturated carboxylic acid copolymer and the third ethylene-unsaturated carboxylic acid copolymer.
• the first ethylene-unsaturated carboxylic acid copolymer is obtained by polymerizing a first monomer component containing ethylene and a first unsaturated carboxylic acid.
• the first unsaturated carboxylic acid is a monomer having at least one ethylenically unsaturated bond and a carboxy group.
• the first unsaturated carboxylic acid include monobasic acids and dibasic acids.
• Examples of the monobasic acids include acrylic acid, methacrylic acid, and crotonic acid.
• Examples of the dibasic acids include maleic acid, fumaric acid, and itaconic acid.
• the first unsaturated carboxylic acid is preferably a monobasic acid. From the viewpoint of improving storage stability, the first unsaturated carboxylic acid is more preferably methacrylic acid. In other words, the first ethylene-unsaturated carboxylic acid copolymer is more preferably a copolymer of ethylene and methacrylic acid.
• the first unsaturated carboxylic acid can be used alone or in combination of two or more types.
• the ethylene content and the first unsaturated carboxylic acid content are appropriately adjusted so that the carboxyl group content A of the first ethylene-unsaturated carboxylic acid copolymer described below falls within a predetermined range.
• the first unsaturated carboxylic acid is methacrylic acid
• the first unsaturated carboxylic acid content is, for example, 1% by mass or more, preferably 5% by mass or more, more preferably 8% by mass or more, and for example, 12% by mass or less, preferably 10% by mass or less, based on the total amount of ethylene and the first unsaturated carboxylic acid.
• the ethylene content is, for example, 88% by mass or more, preferably 90% by mass or more, and for example, 99% by mass or less, preferably 95% by mass or less, more preferably 92% by mass or less, based on the total amount of ethylene and the first unsaturated carboxylic acid.
• the polymerization of the first monomer component is not particularly limited, and a known polymerization method may be used.
• One known polymerization method is, for example, a method in which the first monomer component is contacted with a polymerization initiator (peroxide) under high temperature and high pressure conditions.
• the first ethylene-unsaturated carboxylic acid copolymer can also be prepared as a dispersion in which particles of the first ethylene-unsaturated carboxylic acid copolymer are dispersed in water.
• the weight average molecular weight of the first ethylene-unsaturated carboxylic acid copolymer is, in terms of standard polystyrene measured by gel permeation chromatography (GPC), for example, 8,000 or more, preferably 10,000 or more, and for example, 150,000 or less, preferably 100,000 or less.
• GPC gel permeation chromatography
• the carboxyl group content A and content ratio of the first ethylene-unsaturated carboxylic acid copolymer will be described later.
• the second ethylene-unsaturated carboxylic acid copolymer which will be described in detail later, is a resin having a relatively higher carboxyl group content than the first ethylene-unsaturated carboxylic acid copolymer and a relatively lower carboxyl group content than the third ethylene-unsaturated carboxylic acid copolymer.
• the second ethylene-unsaturated carboxylic acid copolymer is obtained by polymerizing a second monomer component containing ethylene and a second unsaturated carboxylic acid.
• the second unsaturated carboxylic acid may be an unsaturated carboxylic acid similar to the first unsaturated carboxylic acid.
• the second unsaturated carboxylic acid is a monobasic acid.
• the second unsaturated carboxylic acid is methacrylic acid.
• the second ethylene-unsaturated carboxylic acid copolymer is a copolymer of ethylene and methacrylic acid.
• the secondary unsaturated carboxylic acids can be used alone or in combination of two or more types.
• the ethylene content and the second unsaturated carboxylic acid content are appropriately adjusted so that the carboxyl group content B of the second ethylene-unsaturated carboxylic acid copolymer described below falls within a predetermined range.
• the second unsaturated carboxylic acid is methacrylic acid
• the second unsaturated carboxylic acid content is, for example, more than 12% by mass, preferably 14% by mass or more, and, for example, 20% by mass or less, preferably 16% by mass or less, based on the total amount of ethylene and the second unsaturated carboxylic acid.
• the ethylene content is, for example, 80% by mass or more, preferably 84% by mass or more, and, for example, less than 88% by mass, preferably 86% by mass or less, based on the total amount of ethylene and the second unsaturated carboxylic acid.
• the polymerization method for the second monomer component is the same as the polymerization method for the first monomer component.
• the second ethylene-unsaturated carboxylic acid copolymer can also be prepared as a dispersion in which particles of the second ethylene-unsaturated carboxylic acid copolymer are dispersed in water.
• the weight average molecular weight of the second ethylene-unsaturated carboxylic acid copolymer is, in terms of standard polystyrene measured by gel permeation chromatography (GPC), for example, 8,000 or more, preferably 10,000 or more, and for example, 150,000 or less, preferably 100,000 or less.
• GPC gel permeation chromatography
• the carboxyl group content B and content ratio of the second ethylene-unsaturated carboxylic acid copolymer will be described later.
• the third ethylene-unsaturated carboxylic acid copolymer which will be described in detail later, is a resin having a relatively high carboxyl group content compared to the first ethylene-unsaturated carboxylic acid copolymer and the second ethylene-unsaturated carboxylic acid copolymer.
• the tertiary ethylene-unsaturated carboxylic acid copolymer is obtained by polymerizing a third monomer component containing ethylene and a tertiary unsaturated carboxylic acid.
• the third unsaturated carboxylic acid may be an unsaturated carboxylic acid similar to the first unsaturated carboxylic acid.
• the third unsaturated carboxylic acid is a monobasic acid.
• the third unsaturated carboxylic acid is acrylic acid.
• the third ethylene-unsaturated carboxylic acid copolymer is a copolymer of ethylene and acrylic acid.
• first ethylene-unsaturated carboxylic acid copolymer and the second ethylene-unsaturated carboxylic acid copolymer are copolymers of ethylene and methacrylic acid
• the third ethylene-unsaturated carboxylic acid copolymer is a copolymer of ethylene and acrylic acid
• Tertiary unsaturated carboxylic acids can be used alone or in combination of two or more types.
• the content of ethylene and the content of the third unsaturated carboxylic acid are appropriately adjusted so that the carboxyl group content C of the third ethylene-unsaturated carboxylic acid copolymer described below falls within a predetermined range.
• the content of the third unsaturated carboxylic acid is, for example, more than 12 mass%, preferably 14 mass% or more, and for example, 20 mass% or less, preferably 16 mass% or less, based on the total amount of ethylene and the third unsaturated carboxylic acid.
• the content of ethylene is, for example, 80 mass% or more, preferably 84 mass% or more, and for example, less than 88 mass%, preferably 86 mass% or less, based on the total amount of ethylene and the third unsaturated carboxylic acid.
• the polymerization method for the third monomer component is the same as the polymerization method for the first monomer component.
• the third ethylene-unsaturated carboxylic acid copolymer can also be prepared as a dispersion in which particles of the third ethylene-unsaturated carboxylic acid copolymer are dispersed in water.
• the weight average molecular weight of the third ethylene-unsaturated carboxylic acid copolymer is, in terms of standard polystyrene measured by gel permeation chromatography (GPC), for example, 8,000 or more, preferably 10,000 or more, and for example, 150,000 or less, preferably 100,000 or less.
• GPC gel permeation chromatography
• the carboxyl group content C and content ratio of the third ethylene-unsaturated carboxylic acid copolymer will be described later.
• the first ethylene-unsaturated carboxylic acid copolymer, the second ethylene-unsaturated carboxylic acid copolymer, and the third ethylene-unsaturated carboxylic acid copolymer have different carboxyl group contents.
• the carboxyl group content is adjusted to increase in the order of the first ethylene-unsaturated carboxylic acid copolymer, the second ethylene-unsaturated carboxylic acid copolymer, and the third ethylene-unsaturated carboxylic acid copolymer.
• the first ethylene-unsaturated carboxylic acid copolymer has a relatively low carboxyl group content
• the second ethylene-unsaturated carboxylic acid copolymer has a relatively medium carboxyl group content
• the third ethylene-unsaturated carboxylic acid copolymer has a relatively high carboxyl group content.
• the difference (C-B) between the carboxyl group content C of the third ethylene-unsaturated carboxylic acid copolymer and the carboxyl group content B of the second ethylene-unsaturated carboxylic acid copolymer exceeds 0 mmol/kg, and is preferably 0.10 mmol/kg or more, more preferably 0.20 mmol/kg or more, even more preferably 0.30 mmol/kg or more, and is 0.50 mmol/kg or less, preferably 0.40 mmol/kg or less, and more preferably 0.35 mmol/kg or less.
• the difference (B-A) between the carboxyl group content B of the second ethylene-unsaturated carboxylic acid copolymer and the carboxyl group content A of the first ethylene-unsaturated carboxylic acid copolymer exceeds 0 mmol/kg, and is preferably 0.20 mmol/kg or more, more preferably 0.40 mmol/kg or more, even more preferably 0.50 mmol/kg or more, and is 0.80 mmol/kg or less, preferably 0.70 mmol/kg or less, and more preferably 0.60 mmol/kg or less.
• the difference (C-A) between the carboxyl group content C of the third ethylene-unsaturated carboxylic acid copolymer and the carboxyl group content A of the first ethylene-unsaturated carboxylic acid copolymer exceeds 0 mmol/kg, for example, and is preferably 0.20 mmol/kg or more, more preferably 0.40 mmol/kg or more, even more preferably 0.60 mmol/kg or more, particularly preferably 0.90 mmol/kg or more, and is, for example, 1.30 mmol/kg or less, preferably 1.20 mmol/kg or less, more preferably 1.10 mmol/kg or less, even more preferably 1.00 mmol/kg or less, particularly preferably 0.95 mmol/kg or less.
• the carboxyl group content A of the first ethylene-unsaturated carboxylic acid copolymer is, for example, 1.00 mmol/kg or more, preferably 1.04 mmol/kg or more, more preferably 1.10 mmol/kg or more, even more preferably 1.15 mmol/kg or more, and is, for example, less than 1.40 mmol/kg, preferably 1.30 mmol/kg or less, more preferably 1.20 mmol/kg or less.
• the carboxyl group content B of the second ethylene-unsaturated carboxylic acid copolymer is, for example, 1.40 mmol/kg or more, preferably 1.50 mmol/kg or more, more preferably 1.60 mmol/kg or more, even more preferably 1.70 mmol/kg or more, and is, for example, less than 1.80 mmol/kg, preferably 1.75 mmol/kg or less.
• the carboxyl group content C of the third ethylene-unsaturated carboxylic acid copolymer is, for example, 1.80 mmol/kg or more, preferably 1.90 mmol/kg or more, more preferably 2.00 mmol/kg or more, and for example, less than 2.30 mmol/kg, preferably 2.20 mmol/kg or less, more preferably 2.10 mmol/kg or less.
• the content of the first ethylene-unsaturated carboxylic acid copolymer is, for example, 10 parts by mass or more, preferably 20 parts by mass or more, more preferably more than 20 parts by mass, even more preferably 20 parts by mass or more, particularly preferably 30 parts by mass or more, and for example, 70 parts by mass or less, preferably 60 parts by mass or less, more preferably 50 parts by mass or less, even more preferably 40 parts by mass or less, particularly preferably 35 parts by mass or less, relative to 100 parts by mass of the total amount of the first ethylene-unsaturated carboxylic acid copolymer, the second ethylene-unsaturated carboxylic acid copolymer, and the third ethylene-unsaturated carboxylic acid copolymer.
• the content of the second ethylene-unsaturated carboxylic acid copolymer is, for example, 5 parts by mass or more, preferably 10 parts by mass or more, more preferably 15 parts by mass or more, and for example, 50 parts by mass or less, preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less, relative to 100 parts by mass of the total amount of the first ethylene-unsaturated carboxylic acid copolymer, the second ethylene-unsaturated carboxylic acid copolymer, and the third ethylene-unsaturated carboxylic acid copolymer.
• the content of the third ethylene-unsaturated carboxylic acid copolymer is, for example, 20 parts by mass or more, preferably 30 parts by mass or more, more preferably 40 parts by mass or more, even more preferably more than 40 parts by mass, particularly preferably 45 parts by mass or more, and for example, 80 parts by mass or less, preferably 70 parts by mass or less, more preferably 60 parts by mass or less, even more preferably 50 parts by mass or less, relative to 100 parts by mass of the total amount of the first ethylene-unsaturated carboxylic acid copolymer, the second ethylene-unsaturated carboxylic acid copolymer, and the third ethylene-unsaturated carboxylic acid copolymer.
• the content of the third ethylene-unsaturated carboxylic acid copolymer is preferably greater than or equal to the content of the first ethylene-unsaturated carboxylic acid copolymer. Furthermore, the content of the first ethylene-unsaturated carboxylic acid copolymer is greater than the content of the second ethylene-unsaturated carboxylic acid copolymer.
• the content of the second ethylene-unsaturated carboxylic acid copolymer is, for example, 5 parts by mass or more, preferably 10 parts by mass or more, more preferably 15 parts by mass or more, and for example, 20 parts by mass or less, relative to 100 parts by mass of the total amount of the first ethylene-unsaturated carboxylic acid copolymer, the second ethylene-unsaturated carboxylic acid copolymer, and the third ethylene-unsaturated carboxylic acid copolymer.
• the content of the first ethylene-unsaturated carboxylic acid copolymer is, for example, more than 20 parts by mass, preferably 25 parts by mass or more, more preferably 30 parts by mass or more, and is, for example, 40 parts by mass or less, preferably 35 parts by mass or less, relative to 100 parts by mass of the total amount of the first ethylene-unsaturated carboxylic acid copolymer, the second ethylene-unsaturated carboxylic acid copolymer, and the third ethylene-unsaturated carboxylic acid copolymer.
• the content of the third ethylene-unsaturated carboxylic acid copolymer is, for example, 40 parts by mass or more, preferably more than 40 parts by mass, more preferably 45 parts by mass or more, and for example, 80 parts by mass or less, preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less, relative to 100 parts by mass of the total amount of the first ethylene-unsaturated carboxylic acid copolymer, the second ethylene-unsaturated carboxylic acid copolymer, and the third ethylene-unsaturated carboxylic acid copolymer.
• the ethylene-unsaturated carboxylic acid copolymer is prepared by mixing the first ethylene-unsaturated carboxylic acid copolymer, the second ethylene-unsaturated carboxylic acid copolymer, and the third ethylene-unsaturated carboxylic acid copolymer, and melt-kneading the mixture using a known kneading device.
• the ethylene-unsaturated carboxylic acid copolymer is preferably prepared as a dispersion in which particles of the ethylene-unsaturated carboxylic acid copolymer are dispersed in water.
• Additives can also be added to the ethylene-unsaturated carboxylic acid copolymer dispersion in order to improve production stability.
• additives include pH adjusters, metal ion sequestering agents (e.g., ethylenediaminetetraacetic acid and its salts), molecular weight regulators (chain transfer agents, e.g., mercaptans and low molecular weight halogen compounds), and lubricants (e.g., N-oleyl palmitamide, ethylene bisoleamide, N-stearyl erucamide).
• the proportions of additives added are appropriately set depending on the purpose and application.
• the carboxy groups of the ethylene-unsaturated carboxylic acid copolymer are preferably neutralized from the viewpoint of dispersion stability.
• a neutralizing agent is added to the dispersion of the ethylene-unsaturated carboxylic acid copolymer.
• Examples of the neutralizing agent include basic compounds.
• Examples of the basic compound include inorganic basic compounds and organic basic compounds.
• Examples of the inorganic basic compounds include sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, and cesium hydroxide.
• Examples of the organic basic compounds include ammonia, triethylamine, triethanolamine, diethylamine, and dimethylethanolamine.
• Examples of the neutralizing agent include inorganic basic compounds. A more preferred example of the neutralizing agent is potassium hydroxide.
• the amount of neutralizing agent added is, for example, 5 moles or more and, for example, 200 moles or less, preferably 150 moles or less, per 100 moles of carboxy groups in the ethylene-unsaturated carboxylic acid copolymer.
• Neutralizers can be used alone or in combination of two or more types.
• the ethylene-unsaturated carboxylic acid copolymer dispersion is preferably maintained at a predetermined temperature for a predetermined time.
• the holding conditions are, for example, a holding temperature of 40°C or more, preferably 50°C or more, more preferably 100°C or more, and, for example, 190°C or less, preferably 180°C or less.
• the holding time is, for example, 30 minutes or more, preferably 1 hour or more, more preferably 2 hours or more, and, for example, 12 hours or less, preferably 10 hours or less, more preferably 6 hours or less.
• the degree of neutralization is, for example, 10% or more, preferably 15% or more, and, for example, 60% or less, preferably 50% or less, more preferably 40% or less.
• the degree of neutralization can be measured using infrared absorption spectroscopy.
• the solids concentration of the ethylene-unsaturated carboxylic acid copolymer is, for example, 10% by mass or more, preferably 20% by mass or more, more preferably 30% by mass or more, for example, 60% by mass or less, preferably 50% by mass or less.
• the content of the ethylene-unsaturated carboxylic acid copolymer is, for example, 80% by mass or more, preferably 90% by mass or more, more preferably 95% by mass or more, or, for example, 100% by mass, relative to the resin component.
• the resin component optionally contains other resins.
• polyolefin resins include, for example, polyolefin resins.
• polyolefin resins include polyethylene (e.g., linear low-density polyethylene, high-density polyethylene), polypropylene, propylene-ethylene copolymers, and ethylene-butene copolymers.
• the other resins can be used alone or in combination of two or more types.
• the other resin preferably does not contain any other resin and is composed of an ethylene-unsaturated carboxylic acid copolymer.
• the blending ratio of the resin component to the aqueous dispersion is, for example, 10% by mass or more, preferably 20% by mass or more, more preferably 30% by mass or more, for example, 60% by mass or less, preferably 50% by mass or less.
• the aqueous dispersion is produced by blending the resin components and additives as required. More specifically, the aqueous dispersion is produced by blending a dispersion of an ethylene-unsaturated carboxylic acid copolymer (ethylene-unsaturated carboxylic acid copolymer and water), other resins as required, and additives as required.
• additives examples include curing agents, crosslinking agents, film-forming aids, defoamers, tackifiers, hardness-imparting agents, preservatives, thickeners, antifreeze agents, dispersants, inorganic pigments, and organic pigments.
• the additives are blended in an appropriate ratio.
• the additives can be used alone or in combination of two or more kinds.
• the viscosity (25°C) of the aqueous dispersion is, for example, 100 mPa ⁇ s or more, preferably 120 mPa ⁇ s or more, more preferably 140 mPa ⁇ s or more, even more preferably 150 mPa ⁇ s or more, and, for example, 400 mPa ⁇ s or less, preferably 350 mPa ⁇ s or less, more preferably 300 mPa ⁇ s or less.
• the viscosity can be measured, for example, using a B-type viscometer.
• the aqueous dispersion can be suitably used as an adhesive for bonding substrates together.
• an adhesive contains the aqueous dispersion.
• the adhesive containing the aqueous dispersion is a thermocompression (thermal fusion) type adhesive.
• the up-down direction on the paper surface is the up-down direction (thickness direction), with the upper side of the paper surface being the top side (one side in the thickness direction) and the lower side of the paper surface being the bottom side (the other side in the thickness direction).
• the left-right direction and depth direction on the paper surface are surface directions that are perpendicular to the up-down direction. Specifically, they follow the directional arrows in each figure.
• the laminate 10 includes a first base material 1 and an adhesive layer 2 arranged in that order toward one side in the thickness direction.
• the first substrate 1 has a film shape and is disposed over the entire lower surface of the adhesive layer 2 so as to be in contact with the lower surface of the adhesive layer 2 .
• the first substrate 1 is not particularly limited.
• the first substrate 1 is preferably a resin film, a metal film, or paper.
• materials for the resin film include polymeric materials.
• polymeric materials include olefin resins (e.g., polyethylene, polypropylene), acrylic resins, polyester resins, polycarbonate resins, acrylonitrile-styrene-butadiene copolymer resins (ABS resins), polyamide resins (e.g., nylon), and polyphenylene sulfide resins.
• Examples of materials for the metal film include aluminum, gold, silver, copper, nickel, zinc, titanium, cobalt, indium, and chromium.
• materials for the paper include cellulose.
• the first substrate 1 may be surface-treated as necessary.
• surface treatments include ink (solvent-based or water-based) coating, plating, coupling, and vacuum plasma treatment.
• the thickness of the first substrate 1 is not particularly limited.
• the thickness of the first substrate 1 is, for example, 10 ⁇ m or more, and, for example, 100 ⁇ m or less.
• the adhesive layer 2 is a dried product of an aqueous dispersion.
• the adhesive layer 2 is a heat seal layer.
• the thickness of the adhesive layer 2 is, for example, 0.1 ⁇ m or more and, for example, 10 ⁇ m or less.
• the method for manufacturing the laminate 10 includes a first step of preparing a first substrate 1 and a second step of disposing an adhesive layer 2 on one surface of the first substrate 1 in the thickness direction.
• a first substrate 1 is prepared as shown in FIG. 2A.
• an adhesive layer 2 is disposed on one surface in the thickness direction of the first substrate 1.
• the above-mentioned aqueous dispersion is applied to one surface of the first substrate 1 in the thickness direction, and then dried.
• Application methods include known coating methods such as the bar coat method, curtain coating method, roll coating method, and blade coating method.
• the drying temperature is, for example, 50°C or higher, preferably 80°C or higher, and for example, 120°C or lower.
• the drying time is, for example, 10 seconds or longer, and for example, 120 seconds or shorter.
• an adhesive layer 2 which is a dried product of the aqueous dispersion, is placed on one surface in the thickness direction of the first substrate 1.
• the laminate 10 includes an adhesive layer 2 that is a dried product of the above-mentioned aqueous dispersion. This provides excellent productivity.
• the second substrate 3 is placed on one side of the adhesive layer 2 in the thickness direction, and the first substrate 1 and the second substrate 3 are bonded together by thermocompression (heat sealing).
• the second substrate 3 is not particularly limited. A substrate similar to the first substrate 1 described above is selected as the second substrate 3.
• the first substrate 1 and the second substrate 3 may be the same or different from each other.
• the first substrate 1 and the second substrate 3 are the same, and more preferably, both are metal films (e.g., aluminum films).
• thermocompression bonding conditions are such that the temperature is, for example, 80° C. or more, preferably 100° C. or more, and for example, 190° C. or less, preferably 170° C. or less.
• the thermocompression bonding pressure is 1.5 kg/cm 3 or more and 3.5 kg/cm 3 or less.
• first substrate 1 and the second substrate 3 are bonded together to produce a laminate 10 having the first substrate 1, the adhesive layer 2, and the second substrate 3 arranged in that order toward one side in the thickness direction.
• the adhesive layer 2 of the laminate 10 is disposed on one thickness-wise surface of the first substrate 1, but the adhesive layer 2 may also be disposed on one thickness-wise surface and the other thickness-wise surface of the first substrate 1.
• the second substrate 3 can be disposed on one thickness-wise surface and the other thickness-wise surface of the adhesive layer 2.
• the adhesive layer 2 is placed on the first substrate 1, and the first substrate 1 and the second substrate 3 are bonded together via the adhesive layer 2.
• the adhesive layer 2 can be placed on each of the first substrate 1 and the second substrate 3, and then, as shown in FIG. 3B, the first substrate 1 and the second substrate 3 can be bonded together via the adhesive layer 2.
• the adhesive layer 2 is disposed on the first substrate 1 to produce the laminate 10.
• the laminate 10 can then be folded so that the adhesive layers 2 face each other, and the first substrates 1 can be bonded together. In this way, a bag can be produced.
• the laminate 10 used to produce the bag is a bag material.
• the ethylene-unsaturated carboxylic acid copolymer includes a first ethylene-unsaturated carboxylic acid copolymer, a second ethylene-unsaturated carboxylic acid copolymer, and a third ethylene-unsaturated carboxylic acid copolymer, each of which has a different carboxyl group content.
• the difference (C-B) between the carboxyl group content C of the third ethylene-unsaturated carboxylic acid copolymer and the carboxyl group content B of the second ethylene-unsaturated carboxylic acid copolymer, and the difference (B-A) between the carboxyl group content B of the second ethylene-unsaturated carboxylic acid copolymer and the carboxyl group content A of the first ethylene-unsaturated carboxylic acid copolymer are within a predetermined range. Therefore, the storage stability is excellent.
• the reason is as follows. That is, when the ethylene-unsaturated carboxylic acid copolymer contains a first ethylene-unsaturated carboxylic acid copolymer having a relatively low carboxyl group content, a second ethylene-unsaturated carboxylic acid copolymer having a relatively medium carboxyl group content, and a third ethylene-unsaturated carboxylic acid copolymer having a relatively high carboxyl group content, the aqueous dispersion forms an island-sea structure separated into three phases, a first phase 11, a second phase 12, and a third phase 13, as shown in FIG. 4.
• the first phase 11 is a dispersed phase dispersed within the second phase 12, and is composed of an ethylene-unsaturated carboxylic acid copolymer (i.e., a first ethylene-unsaturated carboxylic acid copolymer) having a relatively low carboxyl group content.
• an ethylene-unsaturated carboxylic acid copolymer i.e., a first ethylene-unsaturated carboxylic acid copolymer having a relatively low carboxyl group content.
• the second phase 12 is a dispersed phase dispersed within the third phase 13, and is made of an ethylene-unsaturated carboxylic acid copolymer (i.e., a second ethylene-unsaturated carboxylic acid copolymer) having a relatively medium carboxyl group content.
• an ethylene-unsaturated carboxylic acid copolymer i.e., a second ethylene-unsaturated carboxylic acid copolymer having a relatively medium carboxyl group content.
• the third phase 13 is made of an ethylene-unsaturated carboxylic acid copolymer having a relatively high carboxyl group content (i.e., a third ethylene-unsaturated carboxylic acid copolymer).
• the aqueous dispersion 2 in Patent Document 1 contains water, resin A (ethylene-acrylic acid copolymer (acrylic acid content: 20.5% by mass)), resin B (ethylene-methacrylic acid copolymer (methacrylic acid content: 15% by mass)), and resin C (ethylene-methacrylic acid copolymer (methacrylic acid content: 10% by mass)).
• resin A has a relatively high carboxyl group content, so resin A forms the third phase 13.
• resin B has a relatively medium carboxyl group content, so resin B forms the second phase 12.
• resin C has a relatively low carboxyl group content, so resin C forms the first phase 11.
• the compatibility of the third ethylene-unsaturated carboxylic acid copolymer, which has a relatively high carboxyl group content, with the first ethylene-unsaturated carboxylic acid copolymer, which has a relatively low carboxyl group content, and the second ethylene-unsaturated carboxylic acid copolymer, which has a relatively medium carboxyl group content, is improved, and resins B and C are uniformly dispersed, making it possible to reduce the size of the first phase 11 and the second phase 12. As a result, uniform particles can be formed, and storage stability can be improved.
• the laminate 10 includes an adhesive layer 2 that is a dried product of the above-mentioned aqueous dispersion. This provides excellent productivity.
• the ethylene-unsaturated carboxylic acid copolymer includes three ethylene-unsaturated carboxylic acid copolymers (a first ethylene-unsaturated carboxylic acid copolymer, a second ethylene-unsaturated carboxylic acid copolymer, and a third ethylene-unsaturated carboxylic acid copolymer), but is not limited thereto, and the ethylene-unsaturated carboxylic acid copolymer can also include four or more ethylene-unsaturated carboxylic acid copolymers.
• the number of ethylene-unsaturated carboxylic acid copolymers is not limited.
• the ethylene-unsaturated carboxylic acid copolymer includes three ethylene-unsaturated carboxylic acid copolymers (a first ethylene-unsaturated carboxylic acid copolymer, a second ethylene-unsaturated carboxylic acid copolymer, and a third ethylene-unsaturated carboxylic acid copolymer).
• Resin 1 ethylene-methacrylic acid copolymer, methacrylic acid content 9% by mass, carboxyl group content 1.05 mmol/kg
• Resin 2 Ethylene-methacrylic acid copolymer, methacrylic acid content 10% by mass, carboxyl group content 1.16 mmol/kg
• Resin 3 Ethylene-methacrylic acid copolymer, methacrylic acid content 15% by mass, carboxyl group content 1.74 mmol/kg
• Resin 4 Ethylene-acrylic acid copolymer, acrylic acid content 15% by mass, carboxyl group content 2.08 mmol/kg
• Resin 5 Ethylene-acrylic acid copolymer, acrylic acid content 18% by mass, carboxyl group content 2.50 mmol/kg
• Examples 1 to 7 ⁇ Production of Water Dispersion> After melt-kneading the components according to the recipe in Table 1, 3.5 parts by mass of potassium hydroxide and 165 parts by mass of deionized water were added to a reaction vessel and stirred. The mixture was then heated to 150° C. and held for 4 hours, and then cooled to room temperature to obtain an aqueous dispersion (solid concentration: 38% by mass).
• the ethylene-unsaturated carboxylic acid copolymer was contacted with hydrochloric acid to remove metal ions in the ethylene-unsaturated carboxylic acid copolymer (demetallation), thereby obtaining an acid copolymer having ionic bonds (intramolecular crosslinking).
• the infrared absorption spectrum of this acid copolymer was measured to determine the peak height b of the absorption at 1700 cm -1 .
• the peak height b corresponds to the number of all carboxyl groups in the acid copolymer.
• the laminate was manufactured according to the following procedure.
• aluminum foil was prepared as the first substrate.
• an adhesive layer was disposed on one surface in the thickness direction of the first substrate.
• the aqueous dispersion of each Example was applied to one surface in the thickness direction of the first substrate with a wire bar so that the coating amount was 3 g/ m2 , and the substrate was dried at 180° C. for 10 seconds.
• an adhesive layer was disposed on one surface in the thickness direction of the first substrate.
• the storage stability was evaluated based on the following criteria, and the results are shown in Table 1.
• ⁇ standard ⁇ 5 The separation rate was less than 3%. 4: The separation rate was 3% or more and less than 10%. 3: The separation rate was 10% or more and less than 15%. 2: The separation rate was 15% or more and less than 30%. 1: The separation rate was 30% or more.
• aqueous dispersion and laminate of the present invention can be used, for example, in the manufacture of packaging materials.

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