Aqueous adhesive composition, adhesive application method, inkjet printing device, fabric conveying member

Abstract

Provided are: an aqueous adhesive composition which maintains adhesiveness and improves water resistance over a wide temperature range; an adhesiveness imparting method; an inkjet printing device; a fabric conveying member therefor; an aqueous pressure-sensitive adhesive composition for forming a pressure-sensitive adhesive layer on the surface of a fabric transport member of an ink-jet textile printing device, the aqueous pressure-sensitive adhesive composition containing: a (meth) acrylic resin containing four or more (meth) acrylate units (A) and one or more (meth) acrylic acid units (B) as constituent units; the glass transition temperature of the (meth) acrylic resin is-25 to-8 DEG C, and the difference between the maximum value and the minimum value of the glass transition temperature of each of the homopolymers comprising the constituent units is 170 DEG C or more.

Description

Technical Field

[0001] The present invention relates to aqueous adhesive compositions. Background Art

[0002] Inkjet recording methods, capable of recording high-definition images using relatively simple equipment, have seen rapid development in various areas. Among these, various studies have been conducted on issues such as discharge stability. For example, Patent Document 1 discloses a conveying device and an image recording device equipped with a displacement suppression member relative to the conveying member, as a printing and dyeing technology utilizing an inkjet method, with the goal of stabilizing the contact between the removal member and the conveying member and improving the recovery performance of the washing water used by the removal member.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-109036 Summary of the Invention

[0006] Technical problem to be solved by the invention

[0007] As shown in Patent Document 1, in inkjet printing technology, cloth is attached to a conveying member such as an endless belt and transported to the printing area. The surface of the conveying member is coated with an adhesive, which provides adhesive properties. The adhesive is also called a bonding agent.

[0008] After printing, the cloth, serving as the recording medium, is peeled from the conveyor and transported to the next process. Meanwhile, since the cloth is reattached to the conveyor after being peeled off, it is necessary to remove ink, lint, and other debris that has adhered to the conveyor during the printing process. Residual debris adhering to the conveyor is typically cleaned with water. Brushes, sponges, and other materials are sometimes used to clean the conveyor.

[0009] The adhesive used in such inkjet printing is typically a hydrophobic resin dissolved in an organic solvent to withstand water washing. Furthermore, in recent years, to reduce environmental impact or improve the working environment, there has been a demand for water-based adhesives that use less organic solvent. However, water-based adhesives have poor durability and water resistance, and the adhesive properties of the adhesive applied to the surface of the transport component tend to decrease with washing, necessitating the application of new adhesive each time washing is performed.

[0010] Furthermore, adhesives used in inkjet printing are required to maintain adhesiveness over a wide temperature range and to have improved durability and water resistance.

[0011] Technical solutions to technical problems

[0012] The aqueous adhesive composition of the present invention is used to form an adhesive layer on the surface of a fabric conveying component of an inkjet printing device, and contains a (meth)acrylic resin, a pH adjuster, and water. The (meth)acrylic resin contains four or more (meth)acrylate units A and one or more (meth)acrylic acid units B as structural units. The (meth)acrylic resin has a glass transition temperature of -25 to -8°C, and a homopolymer composed of the structural units has a maximum and minimum glass transition temperature difference of 170°C or greater.

[0013] The method for imparting adhesiveness of the present invention comprises the step of forming an adhesive layer by attaching the aqueous adhesive composition to the surface of a fabric conveying member of an inkjet printing device.

[0014] The inkjet printing device of the present invention comprises: a conveying mechanism for attaching a cloth to an adhesive layer obtained from the above-mentioned aqueous adhesive composition formed on the surface of a cloth conveying component and conveying the cloth; a recording section for performing printing and dyeing records on the cloth attached to the adhesive layer using an inkjet head; and a cleaning section for cleaning the adhesive layer of the cloth that has been peeled off after the printing and dyeing records.

[0015] The fabric transport member of the inkjet printing device of the present invention has an adhesive layer derived from the above-mentioned aqueous adhesive composition on its surface.

[0016] The inkjet printing method of the present invention comprises: a conveying step of laminating a cloth onto an adhesive layer obtained from the above-mentioned aqueous adhesive composition formed on the surface of a cloth conveying component of an inkjet printing device and conveying the cloth; a recording step of performing printing and recording on the cloth adhered to the adhesive layer using an inkjet head; and a cleaning step of cleaning the adhesive layer of the cloth that has been peeled off after the printing and recording. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic cross-sectional view of an inkjet printing device.

[0018] Figure 2 This is a table showing examples and comparative examples.

[0019] Description of Reference Numerals

[0020] 100: Inkjet printing device; 111, 112: Recording medium conveying rollers; 120: Recording unit; 200: Conveying device; 210: Fabric conveying component; 221, 222: Conveying rollers; 230: Driving motor; 240: Control device; 250: Cleaning unit; 260: Removal component; 300: Recording medium. DETAILED DESCRIPTION

[0021] Hereinafter, an embodiment of the present invention (hereinafter referred to as the "present embodiment") will be described in detail with reference to the accompanying drawings as needed. However, the present invention is not limited thereto and various modifications are possible without departing from the spirit and scope of the present invention. It should be noted that in the drawings, identical elements are denoted by the same reference numerals, and duplicate descriptions are omitted. Furthermore, unless otherwise specified, positional relationships such as up and down, left and right, etc., are based on those shown in the drawings. Furthermore, the dimensional ratios in the drawings are not limited to those shown.

[0022] Note that "(meth)acrylate" is a general term for acrylate and methacrylate. Furthermore, "units" such as "structural unit" and "(meth)acrylate unit" refer to repeating units derived from a monomer when the monomer is polymerized to form a polymer.

[0023] 1. Water-based adhesive composition

[0024] The aqueous adhesive composition according to this embodiment is a composition for forming an adhesive layer on the surface of a fabric transport component of an inkjet printing device, and comprises a (meth)acrylic resin, a pH adjuster, and water. The (meth)acrylic resin comprises four or more (meth)acrylate units A and one or more (meth)acrylic acid units B as structural units. The (meth)acrylic resin has a glass transition temperature of -25°C to -8°C, and the difference between the maximum and minimum glass transition temperatures of a homopolymer composed of the structural units is 170°C or greater.

[0025] In this specification, "fabric" refers to fibers formed into woven, knitted, or nonwoven fabrics. In conventional inkjet printing systems, an adhesive layer is formed on a conveying member, such as an endless belt, and a fabric, serving as a recording medium, is attached to this adhesive layer. The fabric is then conveyed to the printing unit, and after recording is completed, the conveying member and fabric are separated.

[0026] Solvent-based acrylic adhesives have been widely used as adhesives for these fabric transport components. However, solvent-based acrylic adhesives release organic solvents during application, potentially causing adverse effects on human health during use. Furthermore, the use of solvent-based acrylic adhesives requires an exhaust system within the inkjet printing environment, increasing the overall size and cost of the equipment.

[0027] On the other hand, in order to form an adhesive layer by coating an adhesive on the fabric conveying part of the inkjet printing device and to adhere the fabric to the adhesive layer and convey it, it is required to have a moderate adhesive force for attaching and peeling the fabric, and at the same time, it is required to have durability, water resistance, and mechanical strength that can withstand washing and scrubbing for removing thread ends and ink attached to the adhesive layer. However, adhesive layers composed of water-based adhesives have low water resistance, tend to be poor in water resistance such as whitening during use, and have poor mechanical strength such as peeling. In addition, as Figure 1 As shown, when used as a coating on the surface of a fabric conveying member, an adhesive layer composed of a water-based adhesive tends to lose its adhesive properties as the fabric is conveyed over a longer distance, and the durability of the adhesive decreases. Therefore, it is difficult to form an adhesive layer that is composed of a water-based adhesive while exhibiting excellent water resistance, adhesive strength, and mechanical strength.

[0028] Furthermore, the adhesive properties of adhesives are generally significantly affected by temperature. Decreased or increased adhesive properties can reduce fabric transportability and potentially cause clogging within the printing equipment. Therefore, adhesives used in inkjet printing are required to maintain adhesive properties over a wide temperature range.

[0029] To address the above-mentioned technical issues, the aqueous adhesive composition of this embodiment contains a predetermined (meth)acrylic resin, a pH adjuster, and water. This improves water resistance and mechanical strength while maintaining adhesiveness over a wide temperature range. The components of the aqueous adhesive composition are described in detail below.

[0030] 1.1. (Meth)acrylic resin

[0031] The inclusion of a specific (meth)acrylic resin not only further improves the adhesive strength and water resistance of the adhesive layer formed on the fabric transport member, but also maintains adhesiveness over a wide temperature range. (Meth)acrylic resins can be water-soluble resins or resin emulsions dispersed in an aqueous catalyst. In this embodiment, these are collectively referred to as (meth)acrylic resins. The use of (meth)acrylic resins can reduce the environmental burden of organic solvents and tends to further improve the releasability of the fabric in the adhesive layer.

[0032] The (meth)acrylic resin contains four or more (meth)acrylate units A and one or more (meth)acrylic acid units B as structural units.

[0033] The (meth)acrylate unit A is not particularly limited, but preferably contains a structural unit derived from one or more monomers selected from the group consisting of methyl methacrylate (MMA), ethyl methacrylate (EMA), butyl methacrylate (BMA), butyl acrylate (BA), and 2-ethylhexyl acrylate (2EHA). The use of such a (meth)acrylate unit A not only further improves the durability of the adhesive force, water resistance, and mechanical strength of the adhesive layer formed on the fabric transport component, but also tends to maintain adhesiveness over a wide temperature range.

[0034] In addition, it is preferred that the four or more (meth)acrylate units A contain structural units derived from butyl acrylate and structural units derived from butyl methacrylate, with the structural units derived from butyl acrylate and butyl methacrylate being the first and second most abundant structural units, respectively. It should be noted that the structural unit derived from butyl acrylate may be the most abundant structural unit, or the structural unit derived from butyl methacrylate may be the most abundant structural unit. This further improves the durability of the adhesive force, water resistance, and mechanical strength of the adhesive layer formed on the fabric conveying component and tends to maintain adhesiveness over a wider temperature range.

[0035] The content of the structural unit derived from butyl acrylate is preferably 20-35% by mass, 15-40% by mass, 10-45% by mass, or 5-50% by mass relative to the total amount of the (meth)acrylic resin. This further improves the durability of the adhesive force, water resistance, and mechanical strength of the adhesive layer formed on the fabric conveying member and tends to maintain adhesiveness over a wider temperature range.

[0036] The content of the structural unit derived from butyl methacrylate is preferably 45-55% by mass, 40-57.5% by mass, 35-60% by mass, 30-62.5% by mass, 25-65% by mass, or 20-67.5% by mass relative to the total amount of the (meth)acrylic resin. This further improves the durability of the adhesive force, water resistance, and mechanical strength of the adhesive layer formed on the fabric conveying member and tends to maintain adhesiveness over a wider temperature range.

[0037] The content of (meth)acrylic acid units A relative to the total amount of the (meth)acrylic resin is preferably 97-99.9% by mass, 97.5-99.7% by mass, or 98-99.5% by mass. A content of 97% or greater in the (meth)acrylic acid units A tends to further improve water resistance and mechanical strength. Furthermore, a content of 99.9% or less in the (meth)acrylic acid units A tends to further improve the durability of the adhesive force of the adhesive layer formed on the fabric transport component.

[0038] The (meth)acrylate units A preferably contain two or more (meth)acrylate units A1 having a glass transition temperature of 15°C or higher and two or more (meth)acrylate units A2 having a glass transition temperature of -50°C or lower. By containing (meth)acrylate units A1 having a relatively high glass transition temperature and (meth)acrylate units A2 having a relatively low glass transition temperature, the adhesive layer formed on the fabric conveying member not only further improves the durability of the adhesive force, water resistance, and mechanical strength, but also tends to maintain adhesiveness over a wider temperature range.

[0039] The (meth)acrylate units A1 are not particularly limited, and examples thereof include butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA). The content of the (meth)acrylate units A1 relative to the total amount of the (meth)acrylic resin is preferably 35-75%, 45-70%, or 50-65% by mass. By adjusting the content of the (meth)acrylate units A1 within these ranges, the durability of the adhesive force, water resistance, and mechanical strength of the adhesive layer formed on the fabric transport component are further improved, and the adhesiveness tends to be maintained over a wide temperature range.

[0040] The (meth)acrylate units A2 are not particularly limited, and examples thereof include methyl methacrylate (MMA), ethyl methacrylate (EMA), and butyl methacrylate (BMA). The content of the (meth)acrylate units A2 is preferably 25-65% by mass, 30-55% by mass, or 35-50% by mass relative to the total amount of the (meth)acrylic resin. By adjusting the content of the (meth)acrylate units A2 within these ranges, the durability of the adhesive force, water resistance, and mechanical strength of the adhesive layer formed on the fabric transport component are further improved, and the adhesiveness tends to be maintained over a wide temperature range.

[0041] The (meth)acrylic acid unit B is not particularly limited, and examples thereof include acrylic acid (AA) and methacrylic acid (MA).

[0042] The content of the (meth)acrylic acid units B is preferably 0.1-3.0% by mass, 0.3-2.5% by mass, or 0.5-2.0% by mass relative to the total amount of the (meth)acrylic acid resin. When the (meth)acrylic acid units B content is 0.1% by mass or greater, the durability of the adhesive force of the adhesive layer formed on the fabric transport component tends to be further improved. Furthermore, when the (meth)acrylic acid units B content is 3.0% by mass or less, water resistance and mechanical strength tend to be further improved.

[0043] The difference between the maximum and minimum glass transition temperatures of the homopolymers composed of the above-mentioned structural units is 170°C or higher, preferably 170 to 250°C or 172 to 225°C. By setting the difference between the maximum and minimum glass transition temperatures of the homopolymers composed of the above-mentioned structural units to 170°C or higher, the adhesive strength, durability, and mechanical strength of the adhesive layer formed on the fabric transport component are further improved, and the adhesiveness tends to be maintained over a wider temperature range.

[0044] For example, consider a (meth)acrylic resin containing methyl methacrylate (MMA), ethyl methacrylate (EMA), butyl methacrylate (BMA), butyl acrylate (BA), and 2-ethylhexyl acrylate (2EHA) as (meth)acrylate units A, and acrylic acid (AA) as (meth)acrylic acid units B. In this case, acrylic acid (AA) has the highest homopolymer glass transition temperature, at 106°C. Meanwhile, 2-ethylhexyl acrylate (2EHA) has the lowest homopolymer glass transition temperature, at -70°C. Therefore, the difference between the maximum and minimum glass transition temperatures in this case is 176°C.

[0045] The glass transition temperature of the (meth)acrylic resin is -25°C to -8°C, preferably -21°C to -9°C or -18°C to -10°C. When the glass transition temperature of the (meth)acrylic resin is -25°C or higher, the durability of the adhesive strength of the adhesive layer formed on the fabric transport component tends to be further improved. Furthermore, when the glass transition temperature of the (meth)acrylic resin is -8°C or lower, the adhesiveness tends to be further maintained over a wide temperature range.

[0046] In this embodiment, the glass transition temperature can be measured by differential scanning calorimetry (DSC) using a conventionally known method. Furthermore, the glass transition temperature of the (meth)acrylic resin can be adjusted by adjusting the homopolymer glass transition temperature of the polymerizable compound used and the mass ratio of the polymerizable compound used.

[0047] The (meth)acrylic resin content is preferably 30-70% by mass, 35-65% by mass, 40-60% by mass, or 45-55% by mass relative to the total amount of the aqueous adhesive composition. By adjusting the (meth)acrylic resin content within this range, the durability of the adhesive force, water resistance, and mechanical strength of the adhesive layer formed on the fabric transport component are further improved, while also tending to maintain adhesiveness over a wide temperature range. The content relative to the total amount of the aqueous adhesive composition refers to the amount of solids.

[0048] It should be noted that the aqueous adhesive composition may contain resins other than the aforementioned (meth)acrylic resins. Such other resins are not particularly limited, and examples thereof include polyurethane resins.

[0049] pH adjusters

[0050] The pH adjuster is not particularly limited, and examples thereof include inorganic acids (e.g., sulfuric acid, hydrochloric acid, nitric acid, etc.), inorganic bases (e.g., lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonia or ammonium salts, etc.), organic bases (e.g., triethanolamine, diethanolamine, monoethanolamine, tripropanolamine), and organic acids (e.g., adipic acid, citric acid, succinic acid, etc.).

[0051] Among these, ammonia or ammonium salts are preferred. Using such a pH adjuster allows the ammonia to volatilize during the formation of the adhesive layer, facilitating adhesion of the (meth)acrylic resins, thereby forming a coating film that is difficult for water to penetrate. This not only improves the durability and water resistance of the adhesive force of the adhesive layer formed on the fabric transport component, but also tends to maintain adhesiveness over a wider temperature range.

[0052] Furthermore, when the surface of the fabric transport member has a polyurethane resin, the adhesion between the (meth)acrylic resin and the polyurethane resin is further improved due to the action of ammonia or ammonium salt, and the mechanical strength tends to be further improved.

[0053] The pH adjuster content is preferably 0.05-1.50% by mass, 0.10-1.00% by mass, 0.15-0.50% by mass, or 0.20-0.30% by mass relative to the total amount of the aqueous adhesive composition. By adjusting the pH adjuster content within these ranges, the durability and water resistance of the adhesive force of the adhesive layer formed on the fabric transport component can be improved, and the adhesiveness tends to be further maintained over a wide temperature range.

[0054] 1.3. Water

[0055] The water content is preferably 30 to 80 mass %, 35 to 70 mass %, or 40 to 60 mass % relative to the total amount of the aqueous adhesive composition.

[0056] 1.4. Surfactants

[0057] The aqueous adhesive composition may contain a surfactant. The surfactant is not particularly limited, and examples thereof include anionic surfactants, nonionic surfactants, and cationic surfactants.

[0058] Examples of anionic surfactants include alkyl sulfocarboxylates, alkyl diphenyl ether disulfonates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, N-acylamino acids and their salts, N-acylmethyl taurates, alkyl sulfates such as ammonium lauryl sulfate and sodium lauryl sulfate, alkyl sulfate polyoxyalkyl ether sulfates, alkyl sulfate polyoxyethylene alkyl ether phosphates, rosin acid soaps, castor oil sulfate esters, lauryl alcohol sulfate esters, alkylphenol-type phosphates, alkyl-type phosphates, alkylarylsulfonates, diethylsulfosuccinate, diethylhexylsulfosuccinate, and dioctylsulfosuccinate. Commercially available anionic surfactants are not particularly limited, and examples include EMAL 2FG, EMAL TD, LAMTEL AD25 (trade names of Kao Corporation), MONOGEN Y100, MONOGEN Y500T, and HITENOL LA12 (trade names of Daiichi Kogyo Seiyaku Co., Ltd.).

[0059] Examples of nonionic surfactants include acetylene glycol surfactants, silicone surfactants, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, polyoxyethylene hydrogenated castor oil, propylene glycol fatty acid esters, glycerol fatty acid esters, polyglycerol fatty acid esters, sorbitan fatty acid esters, sucrose fatty acid esters, alkyl polyglycosides, alkyl diethanolamides, and alkylamine oxides. Commercially available nonionic surfactants are not particularly limited, but examples include EMULGEN 123P, 430, and 1108 (trade names of Kao Corporation), NEWCOL 1006, 1008, and 1020 (trade names of Nippon Emulsifier Co., Ltd.), and NOIGEN DL-0415, ET-116B, ET-106A, DH-0300, YX-400, and EA-160 (trade names of Dai-ichi Kogyo Seiyaku Co., Ltd.).

[0060] Examples of the cationic surfactant include alkylamine salts, fatty acid amide amine salts, monoalkyl quaternary ammonium salts, dialkyl quaternary ammonium salts, trialkyl quaternary ammonium salts, benzalkonium quaternary ammonium salts, benzethonium chloride, and alkylpyridinium salts.

[0061] In this embodiment, nonionic surfactants are preferred, and more specifically, alkyl ether-based nonionic surfactants are preferred. Furthermore, they are preferably used in combination with anionic surfactants. Using such surfactants tends to maintain durability and water resistance.

[0062] The content of the surfactant is preferably 1 to 7 mass %, 2 to 6 mass %, or 3 to 5 mass % relative to the total amount of the aqueous adhesive composition.

[0063] 1.5. Thickener

[0064] The aqueous adhesive composition preferably contains no or a small amount of a tackifier. If a tackifier is not present or is present in a small amount, the adhesive strength of the adhesive layer and the effect of suppressing the decrease in adhesive strength during scrubbing tend to be more sustained. Representative examples of such tackifiers include rosin-based compounds, terpene-based compounds, and hydrocarbon resins. More specifically, examples include rosin-based compounds such as natural rosin, modified rosin, glycerol ester of natural rosin, glycerol ester of modified rosin, pentaerythritol ester of natural rosin, and pentaerythritol ester of modified rosin; terpene-based compounds such as copolymers of natural terpenes, three-dimensional polymers of natural terpenes, aromatic modified terpene resins, hydrogenated derivatives of aromatic modified terpene resins, terpene phenolic resins, terpene resins (monoterpene, diterpene, triterpene, polyterpene, etc.); hydrocarbon resins such as aliphatic petroleum hydrocarbon resins (C5-based resins), hydrogenated derivatives of aliphatic petroleum hydrocarbon resins, aromatic petroleum hydrocarbon resins (C9-based resins) such as styrene oligomers, and hydrogenated derivatives of aromatic petroleum hydrocarbon resins.

[0065] Preferably, no tackifier is contained. However, if a tackifier is contained, its content is preferably 5% by mass or less, 4% by mass or less, 3% by mass or less, 2% by mass or less, or 1% by mass or less relative to the total amount of the aqueous adhesive composition. By setting the tackifier content within the above range, the adhesive strength of the resulting adhesive layer and the effect of suppressing the reduction in adhesive strength during scrubbing tend to be more sustained. From the same viewpoint, the total content of compounds selected from the group consisting of rosin-based compounds, terpene-based compounds, and hydrocarbon resins is also preferably within the same range as above.

[0066] 1.6. Organic solvents

[0067] From the perspective of reducing environmental impact and human impact, the aqueous adhesive composition of this embodiment preferably does not contain organic solvents subject to the Organic Solvent Poisoning Prevention Regulations (hereinafter referred to as the Organic Regulations) established by the Ministry of Health, Labour and Welfare of Japan. More preferably, it does not contain organic solvents that also include organic solvents not subject to the Organic Regulations. Furthermore, when an organic solvent is contained, the content of the organic solvent is preferably 5.0% by mass or less, 2.5% by mass or less, or 1.0% by mass or less relative to the total amount of the aqueous adhesive composition. This reduces environmental impact and VOCs (volatile organic compounds) during use of the aqueous adhesive composition, thus tending to further improve the work environment.

[0068] 1.7. Coloring Materials

[0069] The aqueous adhesive composition of this embodiment preferably does not contain a coloring material. Furthermore, if a coloring material is contained, the content of the coloring material is preferably 1.0% by mass or less, 0.5% by mass or less, or 0.3% by mass or less relative to the total amount of the aqueous adhesive composition. Thus, the aqueous adhesive composition of this embodiment is clearly distinguished from compositions intended for coloring, such as ink compositions, printing pastes, and coatings.

[0070] 2. Adhesion Imparting Method

[0071] The adhesiveness-imparting method of the present embodiment includes the step of forming an adhesive layer by attaching the aqueous adhesive composition to the surface of a fabric conveying member of an inkjet printing apparatus.

[0072] The adhesive layer forming step is a step of applying the aqueous adhesive composition to the surface of the fabric conveying member to form the adhesive layer. The method for applying the aqueous adhesive composition to the fabric conveying member is not particularly limited. The aqueous adhesive composition may be applied uniformly to the entire surface of the fabric conveying member using a squeegee or the like, or may be applied in a predetermined pattern to a portion of the surface of the fabric conveying member.

[0073] In the adhesive layer formation step, the aqueous adhesive composition may be dried to form the adhesive layer. The drying temperature is preferably 10-60°C or 20-40°C. Furthermore, the drying time is preferably 1-24 hours or 2-8 hours. This tends to further improve the water resistance and mechanical strength of the resulting adhesive layer.

[0074] 3. Inkjet printing and dyeing device

[0075] The inkjet printing device of this embodiment includes: a conveying mechanism that adheres the cloth to the adhesive layer obtained from the above-mentioned aqueous adhesive composition formed on the surface of the cloth conveying component and conveys it; a recording unit that uses an inkjet head to perform printing and recording on the cloth adhered to the adhesive layer; and a cleaning unit that cleans the adhesive layer of the cloth that has been peeled off after printing and recording.

[0076] Reference Figure 1 , the inkjet printing device 100 of this embodiment is described. Figure 1 : is an overall structural diagram of the inkjet printing device 100 including the conveying device 200 of this embodiment. Figure 1 In FIG. 1 , arrows a and b indicate the conveyance direction of the recording medium 300 . Arrows c and d indicate the rotation direction of the cloth conveying member 210 . Arrows e and f indicate the rotation directions of the conveying rollers 221 and 222 .

[0077] The inkjet printing device 100 may also include a conveying device 200 for conveying a recording medium by attaching it to a surface, recording medium conveying rollers 111 and 112, and a recording unit 120. A recording medium 300 arriving from a direction a is pressed against the fabric conveying member 210 by the recording medium conveying roller 111, and the recording medium 300 is attached to the surface of the fabric conveying member 210.

[0078] With the recording medium 300 attached to the surface of the fabric feed member 210, the feed device 200 feeds the recording medium 300 directly below the recording unit 120, and recording is performed on the recording medium 300 by the recording unit 120. The fabric feed member 210 and the recording medium 300 are then separated by the recording medium feed roller 112.

[0079] The recording unit 120 may eject the ink composition etc. by inkjet method. In this embodiment, it is assumed that an inkjet head is used in the recording unit 120 to print on textile cloth as the recording medium 300, but the present invention is not limited to this.

[0080] The transport device 200 may include a pair of transport rollers 221 and 222 , a cloth transport member 210 , a drive motor 230 , a control device 240 , a cleaning unit 250 , and a removal member 260 .

[0081] The conveyor rollers 221 and 222 are rollers used to convey the fabric conveying member 210 in a certain direction. Alternatively, the fabric conveying member 210 may be a belt member having an adhesive layer on its surface, which is wound around the conveyor rollers 221 and 222. The fabric conveying member 210 rotates the conveyor rollers 221 and 222 via a drive motor 230, thereby conveying the recording medium in the direction indicated by arrow c. The control device 240 may also control either or both the conveying device 200 and the inkjet printing device 100.

[0082] The cleaning unit 250 cleans the surface of the fabric transport member 210 after it has been separated from the recording medium 300. The cleaning unit 250 removes components of the recording medium 300 and printing colorants that adhere to the fabric transport member 210 during printing. The cleaning unit 250 may also include a pump (not shown), a water spray nozzle, and a water spray pipe.

[0083] The removal member 260 removes water adhering to the fabric conveying member 210 through the cleaning unit 250. The removal member 260 is not particularly limited; for example, a scraper can be used. The scraper is preferably made of an elastic material. Furthermore, polyurethane is preferred for its wear resistance. The portion in contact with the fabric conveying member 210 can have a rectangular cross-section or a shape with the front end cut off at an angle.

[0084] The fabric conveying member 210 is preferably made of an elastic material. A heater (not shown) may be provided to heat the fabric conveying member 210. During the cleaning process of the fabric conveying member 210, a brush (not shown), a sponge (not shown), or the like may be used to clean the fabric conveying member 210 using a water receiving portion (not shown) that receives cleaning water.

[0085] Examples of the recording medium 300 include fabrics made of natural fibers or synthetic fibers such as silk, cotton, wool, nylon, polyester, and rayon. The fabric may be woven, knitted, or nonwoven.

[0086] 4. Fabric conveying components of inkjet printing and dyeing equipment

[0087] The fabric transport component of the inkjet printing apparatus of this embodiment has an adhesive layer formed on its surface from the aforementioned aqueous adhesive composition. The fabric transport component is not particularly limited; for example, it is preferably made of an elastic material, and particularly preferably contains a polyurethane resin. By using the aqueous adhesive composition in such a fabric transport component, the adhesion between the adhesive layer and the fabric transport component is further improved, thereby enhancing water resistance.

[0088] 5. Inkjet printing and dyeing method

[0089] The inkjet printing method includes: a conveying step of attaching a fabric to an adhesive layer obtained from the above-mentioned aqueous adhesive composition formed on the surface of a fabric conveying component of an inkjet printing device and conveying the fabric; a recording step of using an inkjet head to perform printing and recording on the fabric attached to the adhesive layer; and a cleaning step of cleaning the adhesive layer of the fabric that has been peeled off after printing and recording.

[0090] 5.1. Conveying process

[0091] The conveying step is a step of laminating the fabric to the adhesive layer obtained from the above-mentioned aqueous adhesive composition formed on the surface of the fabric conveying member of the inkjet printing device and conveying the fabric. The laminating method is not particularly limited, such as Figure 1 As shown, a method of pressing and bonding the two together using a conveying roller can be mentioned.

[0092] 5.2. Recording process

[0093] The recording process uses an inkjet head to print on the fabric attached to the adhesive layer. During the recording process, the fabric is conveyed through the adhesive layer on the surface of the fabric conveying member while the member is in contact with the fabric. During this conveyance, ink is ejected from the recording unit 120 and adheres to the fabric. The fabric with ink can then be peeled from the adhesive layer and recovered.

[0094] 5.3. Cleaning process

[0095] The cleaning step is a step of cleaning the adhesive layer of the fabric after printing and recording. This step can remove debris such as thread ends from the fabric that have adhered during the recording step from the surface of the adhesive layer.

[0096] Example

[0097] Hereinafter, the present invention will be described in more detail using Examples and Comparative Examples. However, the present invention is not limited to the following Examples.

[0098] 1. Preparation of aqueous adhesive composition

[0099] In a reactor equipped with a stirrer, reflux condenser, thermometer, nitrogen inlet tube, and dropping funnel, 114 g of ion-exchanged water was added and the temperature was raised to 82°C. Then, a total of 498 g of monomers, 79 g of ion-exchanged water, 34 g of Emulgen 123P (surfactant, trade name, manufactured by Kao Corporation), and 34 g of Hitenol LA12 (surfactant, trade name, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), measured to have the composition ratios shown in Table 1 below, were added and mixed with stirring. To the homogenized solution, 249 g of a 2% by mass aqueous solution of ammonium persulfate as a polymerization initiator was added at 82°C over 1.5 hours.

[0100] After adding all the above ingredients, the mixture was kept warm for 1 hour and then cooled. Deionized water was added, and aqueous ammonia was added as a pH adjuster. The mixture was then filtered through a 150-mesh nylon filter to remove coarse particles, thereby obtaining an aqueous adhesive composition containing a (meth)acrylic resin having the composition described in Table 1.

[0101] The monomers constituting the (meth)acrylic resins listed in Table 1 are as follows. The glass transition temperature of the homopolymer is indicated in parentheses. In Table 1, the total weight of the constituent units is expressed as 100 parts by weight. The glass transition temperature (Tg) of the (meth)acrylic resin was measured using differential scanning calorimetry (DSC) in accordance with JIS K7121.

[0102] 2EHA: 2-ethylhexyl acrylate (-70°C)

[0103] BA: Butyl acrylate (-55℃)

[0104] BMA: Butyl Methacrylate (20℃)

[0105] EMA: Ethyl methacrylate (65°C)

[0106] MMA: Methyl methacrylate (105°C)

[0107] AA: Acrylic acid (106°C)

[0108] MAA: Methacrylic acid (130°C)

[0109] 2. Evaluation Method

[0110] 2.1. Adhesion of the adhesive layer

[0111] A conveyor belt with a urethane surface was installed in an EPSON digital printing machine ML-8000. The aqueous adhesive composition prepared as described above was applied to the conveyor belt and dried to form an adhesive layer. The test environment temperature was then set to 5°C, 20°C, and 35°C, respectively. Figure 1 As shown, the conveyor belt is conveyed in the order of attaching the cloth to the conveyor belt, conveying the cloth, and peeling the cloth off.

[0112] As fabrics, two types of fabrics were used: a thin, transparent British-made organza fabric that is difficult to adhere to and is not resistant to stretching, and a 100% cotton fabric that is easy to adhere to, and the adhesive properties were evaluated.

[0113] The adhesion was evaluated based on the following evaluation criteria when the fabric was fed for 10 m and 10,000 m. The fabric was fed for 10,000 m for durability evaluation.

[0114] (Evaluation Criteria)

[0115] A: It can be transported without peeling.

[0116] B: Partial peeling was sometimes observed during transportation, but transportation was possible.

[0117] C: Peeling occurred during transportation to such an extent that transportation had to be stopped, which was not practical.

[0118] Mechanical strength of the adhesive layer

[0119] Using the above digital dyeing machine ML-8000, such as Figure 1 The mechanical strength of the fabric was evaluated based on the following evaluation criteria when the fabric was fed for 10 m and 10,000 m.

[0120] (Evaluation Criteria)

[0121] A: No adhesive layer peeling off from the fabric conveying member (conveyor belt)

[0122] C: The adhesive layer is peeled off from the fabric conveying member (conveyor belt)

[0123] 2.2. Water resistance of the adhesive layer

[0124] Using the above digital dyeing machine ML-8000, such as Figure 1 The fabric was washed with a water brush as shown. Water resistance was evaluated based on the following evaluation criteria when the fabric was fed for 10 m and 10,000 m. It should be noted that if the adhesive layer was whitened in the visual evaluation, the adhesive strength was also reduced.

[0125] (Evaluation Criteria)

[0126] A: The adhesive layer is transparent.

[0127] B: The adhesive layer is partially whitened.

[0128] C: The entire adhesive layer is whitened.

[0129] 3. Evaluation results

[0130] Table 1 shows the composition and evaluation results of the aqueous adhesive composition used in each example. As shown in Table 1, the aqueous adhesive composition used to form an adhesive layer on the surface of a fabric transport component of an inkjet printing device, by containing a specified (meth)acrylic resin and a pH adjuster, not only further improves the durability of the adhesive force, water resistance, and mechanical strength of the adhesive layer formed on the fabric transport component, but also maintains adhesiveness over a wide temperature range.

[0131] It should be noted that the same test as in Example 1 was conducted using a conveyor belt having a polyester resin on its surface instead of a polyurethane resin. The results confirmed that polyurethane resin, as a material for conveyor belts, exhibits high durability of adhesive strength, water resistance, and mechanical strength, and also exhibits a wide temperature range over which it exhibits adequate adhesive strength. Therefore, the aqueous adhesive composition of this embodiment is suitable for use in fabric conveying components containing polyurethane resin.

Claims

1. A water-based adhesive composition, characterized in that Used to form an adhesive layer on the surface of the fabric conveying component of the inkjet printing device, Contains (meth)acrylic resin, pH adjuster and water, The (meth)acrylic resin contains four or more (meth)acrylate units A and one or more (meth)acrylic acid units B as structural units. The glass transition temperature of the (meth) acrylic resin is -25 to -8°C. The difference between the maximum and minimum glass transition temperatures of the homopolymers composed of the structural units is 170° C. or more.

2. The aqueous adhesive composition according to claim 1, wherein The content of the (meth)acrylic acid unit B is 0.1 to 3.0% by mass based on the total amount of the (meth)acrylic resin.

3. The aqueous adhesive composition according to claim 1, wherein The four or more (meth)acrylate units A include two or more units A1 derived from a (meth)acrylate having a homopolymer glass transition temperature of 15° C. or higher, and two or more units A2 derived from a (meth)acrylate having a homopolymer glass transition temperature of −50° C. or lower.

4. The aqueous adhesive composition according to claim 1, wherein The four or more (meth)acrylate units A contain structural units derived from one or more monomers selected from the group consisting of 2-ethylhexyl acrylate, butyl acrylate, butyl methacrylate, ethyl methacrylate, and methyl methacrylate.

5. The aqueous adhesive composition according to claim 1, wherein The four or more (meth)acrylate units A contain a structural unit derived from butyl acrylate and a structural unit derived from butyl methacrylate, The structural unit derived from butyl acrylate and the structural unit derived from butyl methacrylate are the most abundant structural unit and the second most abundant structural unit.

6. The aqueous adhesive composition according to claim 1, wherein The pH adjuster contains ammonia or an ammonium salt.

7. The aqueous adhesive composition according to claim 1, wherein The cloth feeding member contains a polyurethane resin.

8. A method for imparting adhesion, characterized in that: The method comprises the step of forming an adhesive layer by attaching the aqueous adhesive composition according to any one of claims 1 to 7 to the surface of a fabric conveying member of an inkjet printing device.

9. An inkjet printing and dyeing device, characterized in that: have: A conveying mechanism for conveying a cloth by laminating the cloth to an adhesive layer obtained from the aqueous adhesive composition according to any one of claims 1 to 7 formed on the surface of the cloth conveying member; a recording unit that performs printing and recording on the cloth attached to the adhesive layer using an inkjet head; and The cleaning unit cleans the adhesive layer from which the fabric has been peeled after the printing and recording.

10. A cloth conveying component of an inkjet printing and dyeing device, characterized in that: The adhesive layer is formed on the surface of the adhesive composition according to any one of claims 1 to 7.

11. An inkjet printing method, characterized in that: have: A conveying step of laminating a cloth to an adhesive layer obtained from the aqueous adhesive composition according to any one of claims 1 to 7 formed on the surface of a cloth conveying member of an inkjet printing device and conveying the cloth; a recording step of performing printing and recording on the cloth attached to the adhesive layer using an inkjet head; and The cleaning step is to clean the adhesive layer from which the fabric has been peeled after the printing and recording.

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