Hot melt adhesive and method for manufacturing adhesive

Abstract

To provide a hot-melt adhesive capable of exhibiting a strong adhesive force in a shorter time.SOLUTION: A hot-melt adhesive includes a thermoplastic resin and a first crystalline material. In a differential scan calorimetry of the hot-melt adhesive, Tm-Tc is 20.0°C to 70.0°C inclusive when a peak temperature is Tc (°C) with regard to the highest peak from among exothermic peaks observed in a temperature lowering process at 10°C / min after a temperature rise to 150°C, and a peak temperature is Tm (°C) with regard to the highest peak from among endothermic peaks observed in a temperature rising process at 10°C / min after the temperature lowering process. Weight average molecular weight Mw is 100000 to 400000 with regard to a tetrahydrofuran soluble part of the hot-melt adhesive measured with a gel permeation chromatography.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a hot melt adhesive that is primarily used to bond paper media, and a method for producing an adhesive product using the hot melt adhesive. [Background technology]

[0002] Adhesives are substances that can bond materials by interposing between them, and when adhesives are used to bond materials, they produce products that have good appearance, can bond dissimilar materials, and are highly durable. Therefore, various adhesives are used in a wide range of fields, including furniture, architecture, civil engineering, electrical and electronics, automobiles, packaging (boxes and laminates), medical products, and general households.

[0003] There are various classifications of adhesives, but they can be divided into liquid adhesives, such as the liquid glue commonly used in households, and solid adhesives, such as hot melt adhesives. While a general advantage of liquid adhesives is their strong adhesive strength, one of their disadvantages is that they take a long time to bond. This is due to the following reasons: When liquid adhesives are applied to an adherend, they penetrate the unevenness of the adherend, such as paper, and develop adhesive strength as the water or solvent in the adhesive evaporates and solidifies. Therefore, it takes time for the adhesive to evaporate and dry, and therefore it takes time for adhesive strength to develop. On the other hand, it is precisely because it takes time to solidify that they are able to penetrate the unevenness of the adherend and develop an anchoring effect, thereby developing strong adhesive strength.

[0004] Conversely, while a general advantage of solid adhesives is that they do not require much time to bond, a disadvantage is that they have weak adhesive strength. This is due to the following reasons. Solid adhesives such as hot melt adhesives are softened by heat just before or after application to the substrate, allowing them to penetrate the unevenness of the substrate. They then cool and solidify, exerting adhesive strength. Therefore, the time it takes to cool and solidify is faster than evaporation to dryness. While the short solidification time offers the advantage of quick bonding, the tendency to solidify before penetrating the unevenness makes it difficult to achieve a sufficient anchoring effect and strong adhesive strength. Therefore, there is a demand for adhesives that combine the advantages of both solid and liquid adhesives, i.e., adhesives that can exert strong adhesive strength in a short period of time.

[0005] As an example of adhesive technology that develops strong adhesive strength in a short time, Patent Document 1 discloses a two-component adhesive technology that quickly develops strong adhesive strength through a radical polymerization reaction. As an approach from the solid adhesive side, Patent Document 2 discloses reactive hot melt adhesive technology. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-293015 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-277717 Summary of the Invention [Problem to be solved by the invention]

[0007] Two-component adhesives such as those in Patent Document 1 are an excellent technology that can develop strong adhesive strength in a relatively short time. However, because such technology utilizes chemical reactions such as radical polymerization when curing, the bonded object may be subject to unintended damage such as radical attack. In particular, in the case of printed matter on paper, damage may extend to the printed colorant as well as the paper. Furthermore, although the bonding time is relatively short, the adhesives in Patent Document 1 As described above, this process takes from a few minutes to 60 minutes, so a bonding technique that can be completed in a shorter time is required.

[0008] Reactive hot melt adhesives such as those described in Patent Document 2 are a technology that achieves excellent adhesive strength by moisture curing after rapid initial adhesion through cooling and solidification. This technology also achieves excellent adhesive strength in the final adhesive product, but the time required for moisture curing is an issue.

[0009] The present disclosure provides an adhesive that combines the advantages of both solid and liquid adhesives, i.e., a hot melt adhesive that can develop strong adhesive strength in a shorter time, and a method for producing an adhesive article using the hot melt adhesive. [Means for solving the problem]

[0010] A hot melt adhesive comprising a thermoplastic resin and a first crystalline material, In differential scanning calorimetry of the hot melt adhesive, Among the exothermic peaks observed during the temperature drop process at 10°C / min after heating to 150°C, the peak temperature of the highest peak was defined as Tc (°C). When the peak temperature of the highest endothermic peak observed in the temperature increasing process at 10°C / min after the temperature decreasing process is defined as Tm (°C), Tm-Tc is 20.0°C or higher and 70.0°C or lower, The weight average molecular weight Mw of the tetrahydrofuran soluble portion of the hot melt adhesive measured by gel permeation chromatography is 100,000 or more and 400,000 or less. the law of nature, the thermoplastic resin comprises a styrene-acrylic resin, the content of the styrene-acrylic resin in the thermoplastic resin is 90% by mass to 97% by mass, The styrene-acrylic resin is a styrene-based monomer; at least one unsaturated carboxylic acid ester selected from the group consisting of acrylic acid esters and methacrylic acid esters; a cross-linking agent; is a copolymer of the copolymer contains 70% by mass to 80% by mass of the monomer unit formed by polymerization of styrene; The amount of the structure derived from the crosslinking agent in the thermoplastic resin is 0.1% by mass to 1.0% by mass. Hot melt adhesive. [Effects of the Invention]

[0011] The present disclosure makes it possible to provide an adhesive that combines the advantages of both solid and liquid adhesives, i.e., a hot melt adhesive that can develop strong adhesive strength in a shorter time, and a method for producing an adhesive product using the hot melt adhesive. [Brief explanation of the drawings]

[0012] [Figure 1] Schematic diagram of an image forming apparatus [Figure 2] FIG. 1 is a diagram illustrating attachment of an adhesive unit to a main body of an image forming apparatus; [Figure 3] FIG. 1 is a diagram illustrating a sheet transport path in an image forming apparatus. [Figure 4] A diagram to explain the folding process [Figure 5] FIG. 1 is a perspective view showing the appearance of an image forming apparatus; [Figure 6] FIG. 1 is a diagram illustrating an example of a product output by an image forming apparatus. [Figure 7] Schematic diagram of a process cartridge [Figure 8] Schematic diagram of the evaluation sample [Figure 9] Schematic diagram of the evaluation sample [Figure 10] Schematic diagram of adhesive strength evaluation DETAILED DESCRIPTION OF THE INVENTION

[0013] In the present disclosure, unless otherwise specified, the expressions "XX or more and YY or less" or "XX to YY" representing a numerical range mean a numerical range including the lower and upper limits, which are the endpoints. When a numerical range is described in stages, the upper and lower limits of each numerical range can be combined in any way.

[0014] In order to solve this problem, the inventors of the present invention conducted research based on the adhesion mechanism. As mentioned above, adhesion is the bonding of two substances via an adhesive. At this time, the bonding strength between the adherend and the adhesive is also important in order to achieve strong adhesive strength. Therefore, the inventors investigated techniques to increase the bonding strength between the adherend and the adhesive. In order to increase the bonding strength, first The adhesive must penetrate into the adherend. Since the adherend has some unevenness, the adhesive penetrates and fills these unevenness, thereby exerting an anchoring effect and increasing the bonding strength. A problem with hot melt adhesives is that when the adherend is at room temperature, it is cooled by the adherend and tends to cool and solidify before the hot melt adhesive penetrates. Therefore, the inventors of the present invention considered it important to ensure that there is enough time for the hot melt adhesive to penetrate into the adherend, and conducted research.

[0015] One way to extend the time it takes for the adhesive to cool and solidify is to raise the temperature at which the hot melt adhesive is melted significantly above its melting point. This would allow more time for the adhesive to cool to its melting point. However, while this did extend the time it took to solidify somewhat, it did not allow enough time for the adhesive to penetrate. This is thought to be because, even though the adhesive tries to penetrate into the adherend, the flow path for the adhesive is narrow at the point where it penetrates, so a small amount of adhesive is surrounded by a large amount of adhesive and quickly cools.

[0016] Therefore, the inventors attempted to lower the freezing point at which the adhesive solidifies. While this allowed sufficient time for the adhesive to penetrate into the adherend, even a slight increase in the ambient temperature caused the bonded object to reach its melting point, causing the adhesive to melt and fail to maintain its adhesive strength in high-temperature environments. Lowering the freezing point of a hot melt adhesive thus presents an obstacle to the adhesive's heat resistance, so lowering the freezing point is generally not considered. The inventors conducted research to overcome this obstacle and discovered that the problem could be solved by giving the hot melt adhesive hysteresis characteristics, in which the melting point and freezing point are different. In other words, they believed that the problem could be solved by ensuring that the hot melt adhesive had a low freezing point when it penetrated into the adherend, and a high melting point after it had penetrated and solidified.

[0017] For general substances, including hot melt adhesives, the melting point and freezing point are often nearly the same temperature. For example, the temperature at which water solidifies into ice is 0°C, and the temperature at which ice melts into water is also 0°C. Some organic polymer compounds have hysteresis characteristics where the melting point and freezing point are different, but generally the difference is around 10°C.

[0018] In differential scanning calorimetry of a hot melt adhesive, the peak temperature of the highest exothermic peak observed during the temperature drop process at 10°C / min after heating to 150°C is taken as Tc (°C), and the peak temperature of the highest endothermic peak observed during the temperature rise process at 10°C / min after the temperature drop process is taken as Tm (°C). In this case, the hot melt adhesive must have a Tm-Tc value of 20.0°C or higher and 70.0°C or lower.

[0019] In order to increase the hysteresis characteristics between the melting point and freezing point, it is necessary to set Tm - Tc to 20.0°C or higher. The inventors believe that the mechanism by which this increases the hysteresis characteristics is as follows: A large difference between Tm and Tc generally indicates a slow crystallization rate. They speculate that using a hot melt adhesive with a slow crystallization rate slows down the crystallization of the adhesive, and as a result, the heat generated by crystallization maintains the molten state, making it possible to ensure sufficient time for penetration.

[0020] As a result of the study by the present inventors, it was found that when Tm-Tc is 20.0°C or higher, sufficient adhesive strength could be exhibited due to the large hysteresis characteristics. On the other hand, when Tm-Tc is 70.0°C or lower, adhesion could be achieved in a short time. Tm-Tc is preferably 24.0°C or higher and 50.0°C or lower, and more preferably 28.0°C or higher and 40.0°C or lower. The peak that generates Tm is preferably a peak attributed to the first crystalline material. Furthermore, the peak that generates Tc is preferably a peak attributed to the first crystalline material. It is preferable that:

[0021] There are no particular limitations on the means for controlling Tm-Tc, but an example is to include a thermoplastic resin and a crystalline material in the hot melt adhesive to increase their compatibility. Note that a crystalline material refers to a material that exhibits a clear exothermic or endothermic peak (preferably an exothermic peak and an endothermic peak) when subjected to differential scanning calorimetry on the material alone. The measurement conditions are as follows: 10°C / min The temperature is increased from 20°C to 200°C, then 10°C / min The temperature is lowered from 200°C to 20°C, and then further reduced by 10°C / min The temperature is raised from 20° C. to 200° C. A material in which either an exothermic peak due to crystallization or an endothermic peak due to melting (preferably both) is observed in any of these steps is defined as a crystalline material.

[0022] As a specific method, first, in selecting the materials, a combination of highly compatible substances can be selected for the thermoplastic resin, which is the main material of the hot melt adhesive, and the first crystalline material. It is preferable that the combination of materials is such that the compatibility A of the thermoplastic resin and the first crystalline material, expressed by the following formula (1), is 50% or more and 100% or less. Compatibilization degree A(%)= 100-(100×ΔH(A)) / (ΔH(C)×C / 100) ···(1)

[0023] Here, ΔH(A) represents the calorific value (J / g) of the exothermic peak of the mixed resin A of the thermoplastic resin and the first crystalline material in differential scanning calorimetry. ΔH(C) represents the calorific value (J / g) of the exothermic peak of the first crystalline material in differential scanning calorimetry. C represents the mass ratio (%) of the first crystalline material in the mixed resin A, which is 11.9. The degree of compatibilization A is more preferably 80% or more and 100% or less, and even more preferably 90% or more and 100% or less.

[0024] As a means for further enhancing the compatibility of the thermoplastic resin and the first crystalline material, it is preferable to employ a step of heat treating the hot melt adhesive under the following conditions (step a) and (step b) in the production of the adhesive. It is also possible to enhance compatibility by carrying out the following (step a) before the following (step b). When producing a hot melt adhesive by the suspension polymerization method described below, it is preferable to carry out steps a and b on the slurry after the polymerization step.

[0025] (Step a) A step of heat-treating the hot melt adhesive in the presence of a thermoplastic resin and a first crystalline material for 30 minutes or more (preferably 45 to 90 minutes) at a temperature higher than the melting point of the first crystalline material measured alone using a differential scanning calorimeter. (Step b) After step a, the hot melt adhesive is subjected to a differential scanning calorimeter to determine whether the first crystalline material This is a process in which the material is rapidly cooled to a temperature at least 10°C lower than its melting point as measured by itself.

[0026] In the above (step a), the crystalline material is first heat-treated at a temperature higher than the melting point of the first crystalline material, thereby sufficiently melting the crystalline material and making it compatible with the thermoplastic resin. When the melting point of the first crystalline material is Tm1, the temperature is preferably higher than Tm1 and not higher than (Tm1 + 50°C), more preferably (Tm1 + 10°C) to (Tm1 + 40°C). Note that if the melting point of the crystalline material is high and it is difficult to raise the temperature, the compatibility can be improved by extending the heating time.

[0027] Then, in step b), the mixture is rapidly cooled to a temperature at least 10°C lower than the melting point of the first crystalline material, which allows the mixture to solidify in a soluble state, similar to flash freezing, and is believed to enhance compatibility. The temperature gradient during rapid cooling can be designed as desired depending on the material selected, but a cooling rate of 1°C / sec or higher is preferred, with 3°C / sec or higher being more preferred. There is no particular upper limit, but a rate of 10°C / sec or lower is preferred, with 6°C / sec or lower being more preferred.

[0028] The weight-average molecular weight Mw of the tetrahydrofuran-soluble portion of the hot melt adhesive, as measured by gel permeation chromatography, must be 100,000 or more and 400,000 or less. Having an Mw of 100,000 or more ensures a sufficient anchoring effect after the adhesive solidifies, making it possible to obtain strong adhesive strength. Furthermore, having an Mw of 400,000 or less means that the viscosity when melted is low and the adhesive easily penetrates into the adherend, making it possible to obtain strong adhesive strength. Mw is more preferably 150,000 or more and 350,000 or less, and even more preferably 180,000 or more and 300,000 or less.

[0029] The number average molecular weight Mn of the hot melt adhesive is preferably 5,000 to 50,000, more preferably 10,000 to 40,000. The peak molecular weight Mp is preferably 10,000 to 100,000, more preferably 15,000 to 50,000. The molecular weight can be controlled by the molecular weights of the raw materials that make up the hot melt adhesive. When synthesizing the hot melt adhesive by a polymerization reaction or the like, the molecular weight can be controlled by the polymerization reaction conditions, such as the amount of polymerization initiator and the reaction temperature.

[0030] The glass transition temperature Tg of the thermoplastic resin is preferably 40° C. to 90° C., and more preferably 50° C. to 65° C. The glass transition temperature can be controlled by adjusting the ratio of the raw materials that make up the hot melt adhesive.

[0031] The content of the thermoplastic resin in the hot melt adhesive is preferably 60.0 mass % to 99.9 mass %, more preferably 70.0 mass % to 95.0 mass %, and even more preferably 75.0 mass % to 92.0 mass %.

[0032] The mass ratio of the first crystalline material to the thermoplastic resin (first crystalline material / thermoplastic resin) is preferably 0.05 to 0.50, more preferably 0.10 to 0.40, and even more preferably 0.10 to 0.30.

[0033] The content of tetrahydrofuran-insoluble matter that is not extracted by Soxhlet extraction of a hot melt adhesive using tetrahydrofuran (THF) for 16 hours is preferably 20% by mass or more and 60% by mass or less in the hot melt adhesive. The content of THF-insoluble matter represents the amount of polymer-crosslinked thermoplastic resin in the hot melt adhesive. Crosslinking reactions are also used in curing adhesives to achieve strong adhesion, and a THF-insoluble matter content of 20% or more can exhibit strong adhesive strength. On the other hand, a THF-insoluble matter content of 60% by mass or less results in low viscosity when melted and easy penetration into the bonded material, thereby enabling strong adhesive strength to be obtained. The content of THF-insoluble matter is more preferably 30% by mass or more and 40% by mass or less. The content of THF-insoluble matter can be controlled by the amount of crosslinking agent added, etc.

[0034] The hot melt adhesive preferably further contains a second crystalline material, and the compatibility B between the second crystalline material and the thermoplastic resin, represented by the following formula (2), is preferably 10% or more and less than 50%. Compatibilization degree B(%)= 100-(100×ΔH(B)) / (ΔH(C2)×D / 100) ···(2)

[0035] Here, ΔH(B) represents the calorific value (J / g) of the exothermic peak of the mixed resin B of the thermoplastic resin and the second crystalline material in differential scanning calorimetry. ΔH(C2) represents the calorific value (J / g) of the exothermic peak of the second crystalline material in differential scanning calorimetry. D represents the mass ratio (%) of the second crystalline material in the mixed resin B, which is 1.9. The degree of compatibilization B is more preferably 20% or more and 45% or less, and even more preferably 30% or more and 40% or less. Preferred.

[0036] By incorporating a second crystalline material with low compatibility with the thermoplastic resin, the hot melt adhesive melts quickly when heated, making it possible to obtain even stronger adhesive strength. This is thought to be because the second crystalline material acts as a crystalline nucleus, finely dispersing the first crystalline material throughout the resin, allowing the entire resin to melt quickly when the adhesive is heated.

[0037] The content of the second crystalline material can be designed arbitrarily to suit the selected thermoplastic resin and first crystalline material, but it is preferably 0.5% by mass or more and 5.0% by mass or less in the hot melt adhesive, and more preferably 1.0% by mass or more and 3.0% by mass or less.

[0038] The hot melt adhesive preferably has a Tc of 20°C or higher and 60°C or lower, and a Tm of 50°C or higher and 110°C or lower. A Tc of 20°C or higher enables bonding in a shorter time, and a Tc of 60°C or lower eliminates the need to use excessive energy to melt the hot melt adhesive during bonding. Furthermore, a Tm of 50°C or higher can ensure sufficient heat resistance of the resulting bonded product, and a Tm of 110°C or lower eliminates the need to use excessive energy to melt the hot melt adhesive during bonding.

[0039] Tc can be controlled by selecting the types of thermoplastic resin and first crystalline material and by increasing their compatibility. Specific means for increasing compatibility are as described above. Furthermore, Tm can be controlled by selecting the type of first crystalline material and by providing a crystallization step for the crystalline material after the aforementioned (step b). Tc is more preferably 30°C or higher and 50°C or lower, and even more preferably 35°C or higher and 45°C or lower. Tm is more preferably 55°C or higher and 90°C or lower, and even more preferably 60°C or higher and 80°C or lower.

[0040] The viscosity of the hot melt adhesive at 100°C, measured using a constant load extrusion capillary rheometer, is preferably 20,000 Pa·s or more and 100,000 Pa·s or less. Having a 100°C viscosity within this range allows the adhesive to have an appropriate melt viscosity and to exhibit even stronger adhesive strength. The 100°C viscosity is more preferably 30,000 Pa·s or more and 80,000 Pa·s or less, and even more preferably 40,000 Pa·s or more and 70,000 Pa·s or less. The 100°C viscosity can be controlled by the molecular weight of the hot melt adhesive, the amount of THF-insoluble matter, the glass transition temperature, etc.

[0041] The thermoplastic resin contained in the hot melt adhesive is not particularly limited. Examples include known thermoplastic resins such as polyester resin, vinyl resin, acrylic resin, styrene-acrylic resin, polyethylene, polypropylene, polyolefin, ethylene-vinyl acetate copolymer resin, and ethylene-acrylic acid copolymer resin. A plurality of these resins may be contained.

[0042] The thermoplastic resin preferably contains at least one selected from the group consisting of polyester resin and styrene-acrylic resin, more preferably contains styrene-acrylic resin, and even more preferably contains styrene-acrylic resin and polyester resin. The thermoplastic resin is preferably an amorphous resin. The thermoplastic resin contained in the hot melt adhesive preferably contains at least one selected from the group consisting of polyester resin and styrene-acrylic resin, and more preferably contains styrene-acrylic resin. The content of the styrene-acrylic resin in the thermoplastic resin is preferably 50% by mass to 100% by mass, more preferably 80% by mass to 97% by mass, and even more preferably 90% by mass to 95% by mass. % is more preferable.

[0043] The polyester resin may be a known polyester resin. Specific examples include condensation polymers of dibasic acids and their derivatives (carboxylic acid halides, esters, acid anhydrides) and dihydric alcohols. If necessary, tri- or higher hydric polybasic acids and their derivatives (carboxylic acid halides, esters, acid anhydrides), monobasic acids, tri- or higher hydric alcohols, and monohydric alcohols may also be used.

[0044] Examples of dibasic acids include aliphatic dibasic acids such as maleic acid, fumaric acid, itaconic acid, oxalic acid, malonic acid, succinic acid, dodecylsuccinic acid, dodecenylsuccinic acid, adipic acid, azelaic acid, sebacic acid, and decane-1,10-dicarboxylic acid; and aromatic dibasic acids such as phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, tetrabromophthalic acid, tetrachlorophthalic acid, HET acid, himic acid, isophthalic acid, terephthalic acid, and 2,6-naphthalenedicarboxylic acid. Examples of dibasic acid derivatives include carboxylic acid halides, esters, and acid anhydrides of the above aliphatic and aromatic dibasic acids.

[0045] On the other hand, examples of dihydric alcohols include acyclic aliphatic diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, and neopentyl glycol; bisphenols such as bisphenol A and bisphenol F; alkylene oxide adducts of bisphenol A such as an ethylene oxide adduct of bisphenol A and a propylene oxide adduct of bisphenol A; and aralkylene glycols such as xylylene glycol.

[0046] Examples of trivalent or higher polybasic acids and anhydrides thereof include trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, etc. The content of the polyester resin in the thermoplastic resin is preferably 1% by mass to 10% by mass, and more preferably 2% by mass to 5% by mass.

[0047] The styrene-acrylic resin is a copolymer of at least one selected from the group consisting of unsaturated carboxylic acid esters such as acrylic acid esters and methacrylic acid esters and a styrene-based monomer. The styrene-based monomer preferably includes styrene. The content of the monomer unit polymerized from styrene in the copolymer is preferably 50% to 90% by mass, more preferably 60% to 85% by mass, and even more preferably 70% to 80% by mass. The content of the monomer unit polymerized from at least one selected from the group consisting of unsaturated carboxylic acid esters in the copolymer is preferably 10% to 50% by mass, more preferably 15% to 40% by mass, and even more preferably 20% to 30% by mass.

[0048] Polymerizable monomers that can form the styrene-acrylic resin include styrene-based monomers such as styrene, α-methylstyrene, and divinylbenzene; unsaturated carboxylic acid esters such as methyl acrylate, butyl acrylate, methyl methacrylate, 2-hydroxyethyl methacrylate, t-butyl methacrylate, and 2-ethylhexyl methacrylate; unsaturated carboxylic acids such as acrylic acid and methacrylic acid; unsaturated dicarboxylic acids such as maleic acid; unsaturated dicarboxylic anhydrides such as maleic anhydride; nitrile-based vinyl monomers such as acrylonitrile; halogen-containing vinyl monomers such as vinyl chloride; and nitro-based vinyl monomers such as nitrostyrene. These can be used alone or in combination.

[0049] The unsaturated carboxylic acid ester is preferably a (meth)acrylic acid alkyl ester having an alkyl group with 1 to 8 carbon atoms (more preferably 2 to 6). The styrene-acrylic resin is preferably a copolymer of a (meth)acrylic acid alkyl ester having an alkyl group with 1 to 8 carbon atoms (more preferably 2 to 6) and a monomer containing styrene. The styrene-acrylic resin is preferably a copolymer of a (meth)acrylic acid alkyl ester having an alkyl group with 1 to 8 carbon atoms (more preferably 2 to 6), styrene, and a crosslinking agent.

[0050] It is preferable to add a crosslinking agent when forming a thermoplastic resin. That is, it is preferable that the thermoplastic resin has a crosslinked structure due to the crosslinking agent. The amount of the structure (crosslinked structure) derived from the crosslinking agent in the thermoplastic resin is preferably 0.01% by mass to 1.0% by mass, more preferably 0.1% by mass to 0.5% by mass. Examples of crosslinking agents include the following:

[0051] Divinylbenzene, bis(4-acryloxypolyethoxyphenyl)propane, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol #200, #400, #600 diacrylates, dipropylene glycol diacrylate, polypropylene glycol diacrylate, polyester diacrylate (MANDA Nippon Kayaku), and those in which the above acrylates have been replaced with methacrylates.

[0052] Examples of polyfunctional crosslinking monomers include pentaerythritol triacrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, oligoester acrylate and its methacrylate, 2,2-bis(4-methacryloxypolyethoxyphenyl)propane, diacryl phthalate, triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate, and diaryl chlorendate.

[0053] The first crystalline material contained in the hot melt adhesive is not particularly limited, and can be at least one known material selected from the group consisting of ester waxes, fatty acid metal salts such as zinc stearate and aluminum stearate, and the like. The first crystalline material preferably contains ester wax, and more preferably is ester wax. Ester waxes have a polar ester group moiety and a hydrophobic hydrocarbon moiety, making them effective for a wide range of adherends. Examples of ester waxes that can be used include monoester compounds containing one ester bond per molecule, diester compounds containing two ester bonds per molecule, and polyfunctional ester compounds such as trifunctional ester compounds containing three ester bonds per molecule, tetrafunctional ester compounds containing four ester bonds per molecule, and hexafunctional ester compounds containing six ester bonds per molecule.

[0054] Among them, the first crystalline material preferably contains at least one compound selected from the group consisting of monoester compounds and diester compounds. Specific examples of the monoester compound include waxes containing fatty acid esters as the main component, such as carnauba wax and montan acid ester wax; fatty acid esters from which some or all of the acid components have been deoxidized, such as deoxidized carnauba wax; compounds obtained by hydrogenating vegetable oils; methyl ester compounds having a hydroxy group; and saturated fatty acid monoesters, such as stearyl stearate and behenyl behenate.

[0055] Specific examples of the diester compound include dibehenyl sebacate, nonanediol dibehenate, behenate terephthalate, stearyl terephthalate, etc. The first crystalline material may contain other known waxes in addition to the above compounds.

[0056] Monoester compounds and diester compounds tend to have higher crystallinity and larger endothermic amounts than hydrocarbon waxes and tri- or higher functional ester compounds, which makes it easier to match the melting behavior of the wax when the hot melt adhesive melts during the bonding process, making it easier to achieve the effects of the above physical properties.

[0057] The first crystalline material preferably contains at least one selected from the group consisting of ester waxes represented by the following formulas (3) and (4). TIFF0007739013000001.tif69153

[0058] In the formula, l represents a positive integer of 2 or more and 12 or less (preferably 2 or more and 4 or less), n and m each independently represent a positive integer of 12 or more and 20 or less (preferably 14 or more and 20 or less), p represents a positive integer of 2 or more and 10 or less (preferably 2 or more and 4 or less), and q and r each independently represent a positive integer of 11 or more and 21 or less (preferably 14 or more and 20 or less). The ester waxes represented by formulas (3) and (4) have ester groups close to each other, so they have a strong interaction with the polar groups of the adherend. Therefore, they can be effective on a wide variety of adherends.

[0059] The ester wax is more preferably a compound represented by the following formula (5): The first crystalline material more preferably contains an ester wax represented by the following formula (5). TIFF0007739013000002.tif29153

[0060] In the formula, n and m each independently represent a positive integer of 14 or more and 20 or less. The content of the ester wax is preferably 0.3 parts by mass or more and 30.0 parts by mass or less, more preferably 3.0 parts by mass or more and 25.0 parts by mass or less, and even more preferably 5.0 parts by mass or more and 20.0 parts by mass or less, relative to 100 parts by mass of the thermoplastic resin.

[0061] The second crystalline material preferably includes a hydrocarbon wax such as paraffin wax, microcrystalline wax, Fischer-Tropsch wax, etc. Hydrocarbon waxes crystallize faster than the above-mentioned ester waxes and can effectively act as a crystal nucleating agent for the ester waxes.

[0062] The form of use of the hot melt adhesive is not particularly limited, but it is preferable to use it in powder form because it is easier to apply evenly to the adhesive surface. In particular, the weight average particle size (D4) of the hot melt adhesive is preferably 0.1 μm or more and 100.0 μm or less, more preferably 1.0 μm or more and 30.0 μm or less, and even more preferably 3.0 μm or more and 15.0 μm or less.

[0063] Although the method for producing the hot melt adhesive is not particularly limited, it is preferable to apply a known method for producing toner to obtain a powder having a particle size within the above range, such as a pulverization method, a suspension polymerization method, an emulsion aggregation method, or a solution suspension method.

[0064] Among these, suspension polymerization is preferred from the viewpoint of achieving both strong adhesiveness and shelf life of the hot melt adhesive. From the viewpoint of improving the adhesiveness of the hot melt adhesive, when a low viscosity thermoplastic resin is desired by lowering the Tg and molecular weight, the present inventors have found that the shelf life in a high-temperature, high-humidity environment can be significantly improved by using suspension polymerization. The hot melt adhesive is preferably a hot melt adhesive produced by suspension polymerization.

[0065] In the thermoplastic resin of hot melt adhesives produced by suspension polymerization, resin elongation and particle formation occur simultaneously. The inventors believe that this is due to the entanglement of molecules. In particular, the use of a crosslinking agent significantly improves shelf life.

[0066] In the suspension polymerization method, a first crystalline material, optionally a second crystalline material, other thermoplastic resins, wax, a crosslinking agent, a charge control agent, and other additives are uniformly dispersed in a polymerizable monomer capable of forming a thermoplastic resin to obtain a polymerizable monomer composition. The obtained polymerizable monomer composition is then dispersed in a continuous phase (e.g., an aqueous phase) containing a dispersion stabilizer to form particles of the polymerizable monomer composition (granulation), and the polymerizable monomer is polymerized to obtain a hot melt adhesive.

[0067] The hot melt adhesive may contain a colorant if necessary, but the amount of organic pigment is preferably as small as necessary to improve the crystallization of the hot melt adhesive. The hot melt adhesive preferably contains substantially no organic pigment. "Substantially no organic pigment" means that the hot melt adhesive may contain a trace amount of organic pigment that is inevitably mixed in during the production of the hot melt adhesive. The organic pigment content is preferably 0.0% by mass or more and 1.0% by mass or less, and more preferably 0.0% by mass or more and 0.1% by mass or less.

[0068] The hot melt adhesive may contain known materials such as charge control agents, charge control resins, and pigment dispersants as needed. External additives may be mixed and attached to the surface as needed. Examples of external additives include inorganic fine particles selected from silica fine particles, alumina fine particles, and titania fine particles, or composite oxides thereof. Examples of composite oxides include silica aluminum fine particles and strontium titanate fine particles. The content of the external additive is preferably 0.01% by mass or more and 10.0% by mass or less, and more preferably 0.1% by mass or more and 4.0% by mass or less.

[0069] When the hot melt adhesive is used in the form of a powder, an electrophotographic developer containing a toner and a powder adhesive is used to develop an electrostatic latent image on a recording material using an electrophotographic method, and form a toner image and an adhesive portion made of the powder hot melt adhesive (hereinafter also referred to as "powder adhesive"). The toner and the powder adhesive may be used as a set. Utilizing an electrophotographic system is preferred because the adhesive application range can be precisely controlled. An example of a method for producing a paper bag by an electrophotographic system using an electrophotographic developer set containing the above toner and powder adhesive will now be described.

[0070] First, an electrophotographic method is used to form and develop an image area using toner and an adhesive area using a powder adhesive on paper (developing process). Then, heating is applied to fix the image area and adhesive area onto the paper (fixing process). Paper is then stacked with the adhesive area in between, and further heating is applied to melt and adhere the adhesive area (adhesion process), producing a paper bag. The paper can be stacked by folding the paper or by placing a different paper on top of it.

[0071] An example of an image forming apparatus and a processing apparatus for performing adhesive processing on paper, in which an electrophotographic developer set containing a toner and a powder adhesive can be suitably used, will be specifically described below.

[0072] (Overall device configuration) First, the overall configuration of the image forming apparatus will be described with reference to Figures 1, 2, and 5. Figure 1 is a schematic diagram showing the cross-sectional configuration of an image forming apparatus 1 that includes an image forming apparatus main body (hereinafter referred to as apparatus main body 10) and a post-processing unit 30 connected to the apparatus main body 10. The image forming apparatus 1 is an electrophotographic image forming apparatus (electrophotographic system) that includes the apparatus main body 10 that includes an electrophotographic printing mechanism and the post-processing unit 30 that serves as a sheet processing device.

[0073] FIG. 5 is a perspective view showing the appearance of the image forming apparatus 1. The post-processing unit 30 is attached to the top of the apparatus main body 10. The image forming apparatus 1 has a sheet cassette 8 at the bottom, an openable tray 20 on the right side, and a first discharge tray 13 on the top. First, the internal configuration of the apparatus main body 10 will be described. As shown in FIG. 1, the apparatus main body 10 includes the sheet cassette 8 as a sheet storage section for storing sheets P as recording media, an image forming unit 1e as image forming means, a first fuser 6 as fuser means, and a housing 19 that houses these components. The apparatus main body 10 has a printing function in which the image forming unit 1e forms a toner image on the sheet P fed from the sheet cassette 8, and the toner image is then fixed by the first fuser 6 to produce a printed product.

[0074] The sheet cassette 8 is inserted into the housing 19 at the bottom of the device main body 10 so as to be removable, and stores a large number of sheets P. The sheets P stored in the sheet cassette 8 are fed from the sheet cassette 8 by a feeding member such as a feeding roller, and are separated one by one by a pair of separation rollers and then transported by a transport roller 8a. It is also possible to feed sheets set in an open tray 20 (FIG. 5) one by one.

[0075] The image forming unit 1e is a tandem electrophotographic unit equipped with four process cartridges 7n, 7y, 7m, and 7c, a scanner unit 2, and a transfer unit 3. A process cartridge is a unit in which multiple components responsible for the image forming process are integrated into one replaceable unit. The apparatus main body 10 is provided with a cartridge support portion 9 supported by a housing 19, and the process cartridges 7n, 7y, 7m, and 7c are detachably mounted in mounting portions 9n, 9y, 9m, and 9c provided on the cartridge support portion 9. The cartridge support portion 9 may be a tray member that can be pulled out from the housing 19.

[0076] Each of the process cartridges 7n, 7y, 7m, and 7c has a substantially common configuration except for the type of powder contained in the four powder containers 104n, 104y, 104m, and 104c. That is, each of the process cartridges 7n, 7y, 7m, and 7c includes a photosensitive drum 101 as an image carrier, a charging roller 102 as a charger, a powder container 104n for containing powder, 104y, 104m, 104c, and a developing roller 105 that performs development using powder.

[0077] Of the four powder storage units, the three powder storage units 104y, 104m, and 104c on the right side in the drawing contain yellow, magenta, and cyan printing toners Ty, Tm, and Tc, respectively, as toners (first powders) for forming a visible image on the sheet P. In contrast, the powder storage unit 104n on the far left in the drawing contains powder adhesive Tn, which is powder (second powder) for performing an adhesion process after printing.

[0078] The powder containers 104y, 104m, and 104c are all examples of a first container that contains printing toner, and the powder container 104n is an example of a second container that contains powder adhesive. The process cartridges 7y, 7m, and 7c are all examples of a first process unit that forms a toner image using printing toner, and the process cartridge 7n is an example of a second process unit that forms a powder adhesive image in a predetermined application pattern.

[0079] When printing black images such as text, they are expressed using process black, which is a combination of yellow (Ty), magenta (Tm), and cyan (Tc) toners. However, for example, a fifth process cartridge using black printing toner may be added to image forming unit 1e so that black images can be expressed using black printing toner. However, this is not limited to this, and the type and number of printing toners can be changed depending on the application of image forming device 1.

[0080] The scanner unit 2 is disposed below the process cartridges 7n, 7y, 7m, and 7c and above the sheet cassette 8. The scanner unit 2 is an exposure means that irradiates the photosensitive drum 101 of each of the process cartridges 7n, 7y, 7m, and 7c with laser light G to write an electrostatic latent image thereon.

[0081] The transfer unit 3 includes a transfer belt 3a as an intermediate transfer body (secondary image carrier). The transfer belt 3a is a belt member wound around a secondary transfer inner roller 3b and a tension roller 3c, and its outer circumferential surface faces the photosensitive drums 101 of the process cartridges 7n, 7y, 7m, and 7c.

[0082] On the inner circumferential side of the transfer belt 3a, primary transfer rollers 4 are arranged at positions corresponding to the photosensitive drums 101. Furthermore, secondary transfer rollers 5 as transfer means are arranged at positions facing the secondary transfer inner rollers 3b. A transfer nip 5n between the secondary transfer roller 5 and the transfer belt 3a is a transfer portion (secondary transfer portion) where a toner image is transferred from the transfer belt 3a to the sheet P.

[0083] The first fixing device 6 is disposed above the secondary transfer roller 5. The first fixing device 6 is a thermal fixing type fixing device having a heating roller 6a as a fixing member and a pressure roller 6b as a pressure member. The heating roller 6a is heated by a heating element such as a halogen lamp or ceramic heater or by an induction heating type heating mechanism. The pressure roller 6b is pressed against the heating roller 6a by a biasing member such as a spring, and generates a pressure to pressurize the sheet P passing through the nip portion (fixing nip 6n) between the heating roller 6a and the pressure roller 6b.

[0084] The housing 19 is provided with a discharge port 12 (first discharge port) which is an opening for discharging the sheet P from the device body 10, and a discharge unit 34 is disposed in the discharge port 12. The discharge unit 34, which is a discharge means, uses a so-called triple roller set having a first discharge roller 34a, an intermediate roller 34b, and a second discharge roller 34c.

[0085] Further, a switching guide 33, which is a flap-shaped guide for switching the conveying path of the sheet P, is provided between the first fixing device 6 and the discharge unit 34. The switching guide 33 is provided on the shaft portion 3. The tip 33b can rotate around 3a so as to reciprocate in the direction of the arrow c in the figure.

[0086] The device main body 10 is equipped with a mechanism for double-sided printing. A motor (not shown) is connected to the discharge unit 34, and the discharge unit 34 is configured to be able to rotate the intermediate roller 34b forward and backward. A double-sided conveyance path 1r is also provided as a conveyance path connected in a loop to the main conveyance path 1m. While passing through the main conveyance path 1m, the sheet P, on whose first side an image has been formed, is sandwiched and conveyed between the first discharge roller 34a and the intermediate roller 34b by the switching guide 33, which has been rotated clockwise.

[0087] After the trailing edge of the sheet P in the traveling direction passes through the switching guide 33, the switching guide 33 rotates counterclockwise and the intermediate roller 34b rotates in the reverse direction, so that the sheet P is reversed and conveyed to the double-sided conveying path 1r. Then, while the sheet P passes through the main conveying path 1m again in an inverted state, an image is formed on the second side of the sheet P.

[0088] After double-side printing, the sheet P is nipped and conveyed between the intermediate roller 34b and the second discharge roller 34c by the switching guide 33 which has rotated counterclockwise, and is then discharged from the apparatus main body 10. In addition, the conveying path which passes through the conveying roller 8a, the transfer nip 5n, and the fixing nip 6n in the apparatus main body 10 constitutes the main conveying path 1m along which an image is formed on the sheet P. When viewed from the main scanning direction during image formation (the width direction of the sheet which is perpendicular to the conveying direction of the sheet conveyed along the main conveying path 1m), the main conveying path 1m extends from below to above, passing along one side in the horizontal direction with respect to the image forming unit 1e.

[0089] In other words, the device main body 10 is a so-called vertical conveyance type (vertical path type) printer in which the main conveyance path 1m extends in a substantially vertical direction. When viewed vertically, the first discharge tray 13, the intermediate path 15, and the sheet cassette 8 overlap one another. Therefore, the horizontal direction in which the sheet P moves when the discharge unit 34 discharges the sheet P is opposite to the horizontal direction in which the sheet P moves when the sheet P is fed from the sheet cassette 8.

[0090] 1 (when viewed in the main scanning direction during image formation), it is preferable that the horizontal area occupied by the main body portion of post-processing unit 30, excluding second discharge tray 35, is within the area occupied by device main body 10. By accommodating post-processing unit 30 in the space above device main body 10 in this way, it becomes possible to install image forming apparatus 1 with adhesive printing function in an installation space approximately the same as that of a normal vertical pass printer.

[0091] (Adhesive unit) As shown in Fig. 2, post-processing unit 30 is attached to the upper part of apparatus main body 10. Post-processing unit 30 is a post-processing unit in which folder 31 as a folding means and second fixing device 32 as an adhesive means (second fixing means) are housed and integrated in housing (second housing) 39.

[0092] The post-processing unit 30 is provided with a first discharge tray 13 that rotatably holds a tray switching guide 13a, an intermediate path 15, and a second discharge tray 35. The first discharge tray 13 is provided on the upper surface of the post-processing unit 30 and is also located on the upper surface (FIG. 1) of the entire image forming apparatus 1. The functions of each part of the post-processing unit 30 will be described later.

[0093] The post-processing unit 30 is provided with a positioning portion (for example, a convex shape that engages with a recess of the housing 19) for positioning the housing 39 relative to the housing 19 (first housing) of the apparatus main body 10. The post-processing unit 30 is also provided with a drive source and control unit separate from the apparatus main body 10, and a connector 36 of the post-processing unit 30 and a connector 37 of the apparatus main body 10 are connected. This electrically connects the post-processing unit 30 to the device main body 10. As a result, the post-processing unit 30 is in a state where it operates based on commands from a control unit provided in the device main body 10 using power supplied via the device main body 10.

[0094] (Process cartridge) As mentioned above, each of the process cartridges 7n, 7y, 7m, and 7c has a substantially common configuration except for the type of powder contained in each of the four powder containers 104n, 104y, 104m, and 104c. Here, the process cartridge 7n will be described as a representative. Figure 7 is a schematic cross-sectional view of the process cartridge 7n. The process cartridge 7n is made up of a photosensitive unit CC including a photosensitive drum 101 and the like, and a developing unit DT including a developing roller 105 and the like.

[0095] A photosensitive drum 101 is rotatably mounted on the photosensitive unit CC via a bearing (not shown). The photosensitive drum 101 receives a driving force from a driving motor (not shown) as a driving means (driving source) and is driven to rotate in a clockwise direction (arrow w) in the drawing in response to an image forming operation. The photosensitive unit CC also has a charging roller 102 for charging the photosensitive drum 101 and a cleaning member 103 arranged around the photosensitive drum 101.

[0096] The developing unit DT is provided with a developing roller 105 as a developer carrier that rotates counterclockwise (arrow d) in the figure in contact with the photosensitive drum 101. The developing roller 105 and the photosensitive drum 101 each rotate so that their surfaces move in the same direction at the opposing portion (contact portion).

[0097] The developing unit DT is also provided with a developer supply roller 106 (hereinafter simply referred to as the "supply roller") as a developer supply member that rotates in a clockwise direction (arrow e) in the drawing. The supply roller 106 and the developing roller 105 each rotate so that their surfaces move in the same direction at their opposing portions (contact portions).

[0098] The supply roller 106 supplies powder adhesive (printing toner in the case of process cartridges 7y, 7m, and 7c) onto the developing roller 105, and also acts to peel off any powder adhesive (printing toner in the case of process cartridges 7y, 7m, and 7c) remaining on the developing roller 105 from the developing roller 105.

[0099] In addition, the developing unit DT is provided with a developing blade 107 as a developer regulating member that regulates the layer thickness of the powder adhesive (printing toner in the case of process cartridges 7y, 7m, and 7c) supplied onto the developing roller 105 by the supply roller 106.

[0100] The powder container 104n contains a powder adhesive (printing toner in the case of the process cartridges 7y, 7m, and 7c) as the powder. A rotatably supported transport member 108 is provided within the powder container 104n. The stirring member 108 rotates in a clockwise direction (indicated by arrow f) in the drawing to stir the powder contained in the powder container 104n and transport the powder to a developing chamber 109 in which the developing roller 105 and supply roller 106 are provided.

[0101] Here, the photosensitive unit CC and the developing unit DT may be separately configured as a photosensitive unit cartridge and a developing unit cartridge, respectively, which may be configured to be detachable from the main body of the image forming apparatus. Alternatively, it may be configured as a powder cartridge that has only the powder container 104 and the conveying member 108 and is detachable from the main body of the apparatus.

[0102] (Image formation operation) Next, the image forming operation performed by the image forming apparatus 1 will be described with reference to FIGS. 3(a) and 3(b) are diagrams showing the sheet transport path in the image forming apparatus 1. FIGS. 4(a) to 4(f) are diagrams for explaining the contents of the folding process. FIGS. 6(a) and 6(b) are diagrams showing examples of the product output by the image forming apparatus 1.

[0103] When data of an image to be printed and a command to execute printing are input to the image forming apparatus 1, the control unit of the image forming apparatus 1 starts a series of operations (image forming operation) to convey the sheet P, form an image on it, and, if necessary, perform post-processing by the post-processing unit 30. In the image forming operation, first, as shown in Fig. 1, the sheets P are fed one by one from the sheet cassette 8 and conveyed toward the transfer nip 5n via the conveying roller 8a.

[0104] In parallel with the feeding of the sheet P, the process cartridges 7n, 7y, 7m, and 7c are driven sequentially, and the photosensitive drums 101 are driven to rotate in the clockwise direction (arrow w) in the figure. At this time, a uniform charge is applied to the surface of the photosensitive drum 101 by the charging roller 102. In addition, the scanner unit 2 irradiates the photosensitive drums 101 of each of the process cartridges 7n, 7y, 7m, and 7c with laser light G modulated based on image data, thereby forming an electrostatic latent image on the surface of the photosensitive drum 101. Next, the electrostatic latent image on the photosensitive drum 101 is developed into a powder image by powder carried by the developing rollers 105 of each of the process cartridges 7n, 7y, 7m, and 7c.

[0105] The powder adhesive layer formed on the photosensitive drum 101 by development with the powder adhesive Tn differs from a toner image (normal toner image) of printing toner used to record images such as figures and text on the sheet P in that it is not intended to transmit visual information. However, in the following description, the layer of powder adhesive Tn developed in a shape corresponding to the application pattern by an electrophotographic process in order to apply the powder adhesive Tn to the sheet P in a predetermined application pattern will also be treated as one of the "toner images."

[0106] The transfer belt 3a rotates counterclockwise (arrow v) in the figure. The toner images formed in each of the process cartridges 7n, 7y, 7m, and 7c are primarily transferred from the photosensitive drum 101 to the transfer belt 3a by an electric field formed between the photosensitive drum 101 and the primary transfer roller 4. The toner images carried on the transfer belt 3a and reaching the transfer nip 5n are secondarily transferred onto the sheet P transported along the main transport path 1m by an electric field formed between the secondary transfer roller 5 and the inner secondary transfer roller 3b.

[0107] Thereafter, the sheet P is conveyed to the first fixing device 6 and subjected to a thermal fixing process. That is, when the sheet P passes through the fixing nip 6n, the toner image on the sheet P is heated and pressurized, causing the printing toners Ty, Tm, Tc and the powder adhesive Tn to melt and then solidify, resulting in a fixed image on the sheet P. Regardless of whether single-sided printing or double-sided printing is performed, the sheet P discharged from the apparatus main body 10 is nipped between the intermediate roller 34b and the second discharge roller 34c, as shown in Figs. 3(a) and 3(b), and is then directed to either the first route R1 or the second route R2 by the tray switching guide 13a. is transported to.

[0108] 3(a) is a path along which, in a normal printing mode that does not use the post-processing unit 30, the sheet P that has passed through the first fixing device 6 is discharged to the first discharge tray 13 by the discharge unit 34. The second path R2 shown in FIG. 3(b) is a path along which, in an adhesive printing mode, the sheet P that has passed through the first fixing device 6 is discharged to the second discharge tray 35 via the discharge unit 34, the folder 31, and the second fixing device 32.

[0109] An intermediate path 15 is provided between the first fixing unit 6 and the folder 31 in the second route R2. The intermediate path 15 is a sheet transport path that passes through the upper surface (top surface) of the image forming apparatus 1, and extends below the first discharge tray 13 and substantially parallel to the first discharge tray 13. The tray 15 and the first discharge tray 13 are inclined vertically upward toward the folder 31 with respect to the horizontal direction. Therefore, the entrance of the folder 31 (the pair of guide rollers (31c, 31d) described below) is located vertically higher than the exit of the device main body 10 (the nip between the intermediate roller 34b and the second discharge roller 34c).

[0110] The folder 31 has four rollers, namely, a first guide roller 31c, a second guide roller 31d, a first folding roller 31a, and a second folding roller 31b, and a lead-in portion 31e. The first guide roller 31c and the second guide roller 31d are a pair of guide rollers that sandwich and transport the sheet P received from a transport path (intermediate path 15 in this embodiment) on the upstream side of the folder 31. The first folding roller 31a and the second folding roller 31b are a pair of folding rollers that feed the sheet P while folding it.

[0111] The distance M (FIG. 1) between the second discharge roller 34c and the first guide roller 31c in the sheet transport direction along the second path R2 is configured to be shorter than the overall length L (FIG. 4(a)) of the sheet P in the transport direction before folding. In other words, the distance M between the second discharge roller 34c and the first guide roller 31c determines the lower limit of the length of the sheet in the transport direction that can be processed by the post-processing unit 30. With this configuration, the sheet P is smoothly delivered from the discharge unit 34 to the pair of guide rollers.

[0112] The folding process by folder 31 will be described with reference to Figures 4(a) to 4(f). When performing the folding process, first guide roller 31c and first folding roller 31a rotate clockwise in the figure, and second guide roller 31d and second folding roller 31b rotate counterclockwise in the figure.

[0113] First, the leading edge q of the sheet P sent out from the discharge unit 34 is pulled into the pair of guide rollers (31c, 31d) as shown in Fig. 4(a). As shown in Fig. 4(b), the leading edge q of the sheet P is guided downward by the guide wall 31f, contacts the first folding roller 31a, is pulled into the opposing first folding roller 31a and second guide roller 31d, and abuts against the wall 31g of the pull-in portion 31e.

[0114] As the guide roller pair (31c, 31d) pulls in the sheet P, the leading edge q slides against the wall 31g and advances deeper into the pull-in section 31e. Eventually, the leading edge q hits the end 31h of the pull-in section 31e, as shown in FIG. 4(c). The pull-in section 31e forms a space below the intermediate path 15 that extends substantially parallel to the intermediate path 15, and at the stage shown in FIG. 4(c), the sheet P wraps around the second guide roller 31d and is bent into a U-shape.

[0115] When the guide roller pair (31c, 31d) further pulls the sheet P from the state shown in FIG. 4(c), the sheet P begins to bend at the middle portion r as shown in FIG. 4(d). Eventually, as shown in FIG. 4(e), the middle portion r comes into contact with the second folding roller 31b, and the sheet P is pulled into the nip portion of the folding roller pair (31a, 31b) by the frictional force received from the second folding roller 31b. Then, as shown in FIG. 4(f), the sheet P is folded with the middle portion r as the crease, and is discharged by the folding roller pair (31a, 31b) with the middle portion r leading.

[0116] Here, the depth N of the retraction portion 31e (FIG. 4(e)), i.e., the distance from the nip portion of the pair of folding rollers (31a, 31b) to the end portion 31h of the retraction portion 31e, is set to half the total length L of the sheet P. This allows the folder 31 to fold the sheet P in half (center folding). Note that by changing the depth N of the retraction portion 31e, the position of the fold can be changed as desired.

[0117] The folder 31 described above is an example of a folding means, and a folding mechanism may be used, for example, by pressing a blade against the sheet P and forcing it into the nip between a pair of rollers to form a crease. Furthermore, the folding process is not limited to folding in half, and a folding mechanism that performs, for example, Z-folding or three-folding may be used.

[0118] Since folder 31 is composed of rotating rollers and fixed retraction section 31e, the drive mechanism can be simplified compared to a folding mechanism that uses a reciprocating blade. Furthermore, folder 31 only needs to be provided with retraction section 31e, which has a depth N that is half the sheet length, in addition to the four rollers, so post-processing unit 30 can be made smaller.

[0119] The sheet P that has passed through the folder 31 is conveyed to the second fixer 32 as shown in FIG. 3(b). The second fixer 32 has a thermal fixing configuration similar to the first fixer 6. That is, the second fixer 32 has a heating roller 32b as a heating member and a pressure roller 32a as a pressure member. The heating roller 32b is heated by a heating element such as a halogen lamp or a ceramic heater, or by a heat generating mechanism of an induction heating type.

[0120] The pressure roller 32a is pressed against the heating roller 32b by a biasing member such as a spring, and generates a pressure force for pressing the sheet P passing through the nip portion (adhesion nip) between the heating roller 32b and the pressure roller 32a.

[0121] The sheet P folded by the folder 31 is subjected to a bonding process (a second thermal fixation of the image surface on which the powder adhesive Tn has been applied) by the second fixator 32, whereby the sheet P is bonded while remaining in the folded state. That is, when the sheet P passes through the bonding nip, the powder adhesive Tn on the sheet P is heated and remelted, and is then pressurized, so that it adheres to the opposing surface (the surface facing the image surface of the sheet P on which the toner image of the powder adhesive Tn has been transferred in the folded state). Then, the powder adhesive Tn cools and hardens, so that the image surface and the opposing surface of the sheet P are bonded (bonded) together using the powder adhesive Tn as an adhesive.

[0122] As shown in FIG. 3(b), the sheet P that has been subjected to the adhesion process by the second fixing device 32 is discharged to the left side in the drawing from a discharge port 32c (second discharge port) provided in the housing 39 of the post-processing unit 30. Then, the sheet P is stored in a second discharge tray 35 (see FIG. 1) provided on the left side surface of the apparatus main body 10. This completes the image formation operation when the sheet P is transported along the second path R2.

[0123] The bonding locations of the folded sheet P can be changed by varying the application pattern of the powder adhesive Tn on the sheet P. Figures 6(a) and 6(b) show examples of deliverables (output products from an image forming apparatus) with different application patterns of the powder adhesive Tn. Figure 6(a) is an example of a deliverable (semi-adhesive deliverable) intended to be opened by the recipient. In the case of the pay slip 51 in Figure 6(a), the powder adhesive Tn is applied to the entire periphery 51a of one side of the sheet P, and the sheet P is adhered in a folded state at the central fold 51b.

[0124] Figure 6(b) shows a bag (medicine bag) as an example of a product (fully adhesive product) intended for use without being opened. In this case, powder adhesive Tn is applied to a U-shaped region 52a of the folded sheet P so that three sides, including fold 52b, of the folded sheet P are joined. Although no image is formed on the inside of the bag in Figure 6(b), an image can be formed if necessary.

[0125] 6(a) and 6(b), the image forming apparatus 1 can output any of the products exemplified in Fig. 6(a) and Fig. 6(b) in one stop without preparing preprinted paper. That is, in parallel with the operation of recording an image on one or both sides of the sheet P using printing toner, it is possible to apply the powder adhesive Tn in a predetermined application pattern and output a product in a state where the sheet has been folded and glued.

[0126] 6(a) and 6(b), one side of the sheet P used as the base paper becomes the outside of the product, and the other side becomes the inside of the product. Therefore, in double-sided printing, an image for the outside surface is formed with printing toner as the image forming operation for the first side, and an image for the inside surface is formed with printing toner as the image forming operation for the second side, and powder adhesive Tn is applied in a predetermined application pattern.

[0127] The image recorded by the image forming device 1 using printing toner can include both the format (invariant portion) when using preprinted paper and variable portions such as personal information. Therefore, as described above, it is possible to output a product that has been glued together using a gluing process from base paper such as blank paper that is not preprinted paper. However, the image forming device 1 can also be used to perform printing and gluing processes on variable portions using preprinted paper as a recording medium.

[0128] (Method for manufacturing adhesive (result)) A method for producing an adhesive product is a method for producing an adhesive product in which at least one paper is bonded together via an adhesive portion using the above-mentioned hot melt adhesive, A step of forming an adhesive portion by developing the adhesive portion on the paper using a hot melt adhesive and fixing the adhesive portion by heating; a bonding step of, after forming the adhesive joint, stacking papers so as to sandwich the formed adhesive joint and heating the stacked papers to melt the adhesive joint and bond the papers together to obtain the bonded product; During the heating, the temperature Tf (° C.) of the fixing unit and the melting point Tm (° C.) of the hot melt adhesive preferably satisfy the relationship 70≦Tf−Tm≦200.

[0129] The bonded article may have an image area formed by an electrophotographic developer on at least one side of the paper, and the method for producing the bonded article may include a step of developing an image area formed by the electrophotographic developer and an adhesive area formed by a hot melt adhesive on at least one side of the paper, and fixing the image area and the adhesive area by heating. After the image area and the adhesive area are formed, the papers are preferably stacked so as to sandwich the formed adhesive area, and heated as described above.

[0130] The bonded product may be in the form of a single piece of paper folded and bonded together via an adhesive joint, or two pieces of paper bonded together via an adhesive joint. The bonded product may be in the form of, for example, a booklet, a bag, a tube, or the like. When pieces of paper are bonded together via an adhesive joint, the bonded product will have two surfaces with adhesive joints, and the adhesive joint made of powder adhesive may be formed on at least one of the two surfaces. When a bonded product is produced using a single piece of paper, the toner image area and the powder adhesive adhesive may be formed on at least one surface of the paper. An image area may or may not be formed on the other surface of the paper.

[0131] When two sheets of paper are bonded together to produce a bonded product, an image area and an adhesive area are formed on one of the sheets. An image area or an adhesive area may or may not be formed on the other sheet. Either the image area or the adhesive area may be formed first, or both may be formed simultaneously. The image area and the adhesive area may be developed and fixed using, for example, the image forming apparatus described above. A known electrophotographic method may also be employed.

[0132] After forming the image area and adhesive area, if a single sheet of paper is used, the paper is folded to sandwich the adhesive area, or if two sheets of paper are used, the two sheets are stacked and sandwiched together. The adhesive area is then heated to melt the paper and adhere it to the paper, resulting in a bonded product (finished product). This bonding process can be performed, for example, using the fixing device of the image forming apparatus or sheet processing apparatus described above.

[0133] It is preferable that the temperature Tf (°C) of the fixing unit during heating and the melting point Tm (°C) of the hot melt adhesive satisfy the relationship 70≦Tf−Tm≦200. This allows the hot melt adhesive to be sufficiently melted, resulting in strong adhesive strength. By satisfying Tf-Tm≦200, the phenomenon in which the hot melt adhesive is removed by the fixing device (so-called hot offset) is unlikely to occur, making it possible to obtain strong adhesive strength. The temperature of the fixing device, Tf, refers to the surface temperature of the heating element provided in the fixing device. Tf and Tm more preferably satisfy 80≦Tf-Tm≦180, and even more preferably satisfy 100≦Tf-Tm≦160.

[0134] (Adhesive) The hot melt adhesive can be used as an adhesive in an adhesive product in which at least one piece of paper is bonded together via the adhesive. The adhesive is a molten and cured product of the hot melt adhesive. The means for obtaining the adhesive product are not particularly limited. The hot melt adhesive can be applied to a desired portion of a folded piece of paper or between multiple overlapping pieces of paper, followed by heating and, if necessary, pressure. Alternatively, the hot melt adhesive can be placed at a desired position on the paper, and the hot melt adhesive can be fixed to the paper by heat and, if necessary, pressure, to obtain paper with an adhesive portion. The paper with an adhesive portion can then be folded or overlapped with other paper, and heated and, if necessary, pressure can be applied to obtain an adhesive product.

[0135] The means for heating and, if necessary, applying pressure are not particularly limited. A hot plate, a laminator, or the like can be used. A fixing process using an electrophotographic method may also be used. When forming an adhesive portion on paper, a developing process and a fixing process using an electrophotographic method may also be used.

[0136] 1cm when adhesive is peeled off 2 The adhesive strength is 0.5N / cm 2 ~2.5N / cm 2 Preferably, it is 1.0 N / cm 2 ~2.5N / cm 2 More preferably, it is 1.3 N / cm 2 ~2.5N / cm 2The adhesive strength can be measured using a Tensilon universal testing machine RTG-1225 (manufactured by A&D Co., Ltd.) according to the methods described below in (Preparation of evaluation samples) and (Evaluation of adhesive strength).

[0137] The methods for measuring each physical property are described below. <Methods for identifying the molecular structure of thermoplastic resins and crystalline materials, and measuring the content of thermoplastic resins and crystalline materials contained in hot melt adhesives> Pyrolysis gas chromatography mass spectrometry (PGC / MS) and NMR are used to identify the molecular structure of thermoplastic resins and crystalline materials, and to measure the content of thermoplastic resins and waxes contained in hot melt adhesives. Pyrolysis GC / MS can determine the constituent monomers of the entire resin sample and calculate the peak area of ​​each monomer, but quantification requires normalization of peak intensity using a reference sample of known concentration. On the other hand, NMR can determine and quantify the constituent monomers without using a sample of known concentration. Therefore, depending on the situation, the constituent monomers can be determined by comparing the spectra from both NMR and PGC / MS.

[0138] Specifically, when the amount of resin components that are insoluble in deuterated chloroform, the extraction solvent used in NMR measurement, is less than 5.0% by mass, quantification is performed by NMR measurement. On the other hand, when the amount of resin components that are insoluble in deuterated chloroform, the extraction solvent used in NMR measurement, is 5.0% by mass or more, both NMR and pyrolysis GC / MS measurements are performed on the deuterated chloroform soluble fraction, and pyrolysis GC / MS measurement is performed on the deuterated chloroform insoluble fraction. In this case, NMR measurement is first performed on the deuterated chloroform soluble fraction, and the constituent monomers are determined and quantified (quantification result 1). Next, pyrolysis GC / MS measurement is performed on the deuterated chloroform soluble fraction, and the peak areas of the peaks assigned to each constituent monomer are determined. The values ​​obtained by NMR measurement are Using the quantitative results 1 obtained, the relationship between the amount of each constituent monomer and the peak area of ​​pyrolysis GC / MS is determined.

[0139] Next, the deuterated chloroform insoluble fraction is subjected to pyrolysis GC / MS measurement, and the peak area of ​​the peak assigned to each constituent monomer is determined. From the relationship between the amount of each constituent monomer obtained by the measurement of the deuterated chloroform soluble fraction and the peak area of ​​the pyrolysis GC / MS, the constituent monomers in the deuterated chloroform insoluble fraction are quantified (Quantitative Result 2). Then, Quantitative Result 1 and Quantitative Result 2 are combined to obtain the final quantitative result of each constituent monomer. Specifically, the following operations are performed.

[0140] (1) 50 mg of hot melt adhesive is weighed into an 8 mL glass sample bottle, 1 mL of deuterated chloroform is added, the bottle is capped, and the mixture is dispersed and dissolved for 1 hour using an ultrasonic disperser. The mixture is then filtered through a 0.4 μm membrane filter, and the filtrate is recovered. The deuterated chloroform-insoluble matter remains on the membrane filter. (2) Regarding the filtrate: 1 H-NMR measurement is performed, and the spectrum is assigned to each constituent monomer in the resin to determine quantitative values. (3) If analysis of deuterated chloroform insoluble matter is required, analyze it by pyrolysis GC / MS. If necessary, perform derivatization treatment such as methylation.

[0141] (NMR measurement conditions) Bruker AVANCE 500 manufactured by Bruker Biospin Co., Ltd. Measurement nuclei: 1 H Measurement frequency: 500.1MHz Accumulation count: 16 times Measurement temperature: room temperature

[0142] (Pyrolysis GC / MS measurement conditions) Pyrolysis equipment: Japan Analytical Industry Co., Ltd. TPS-700 Thermal decomposition temperature: Optimum value between 400℃ and 600℃ GC / MS equipment: ISQ manufactured by Thermo Fisher Scientific Co., Ltd. Column: "HP5-MS" (Agilent / 19091S-433), length 30 m, inner diameter 0.25 mm, film thickness 0.25 μm GC / MS conditions Filler requirements: Inlet Temp: 250℃ Split Flow: 50 mL / min GC temperature rise conditions: 40°C (5 min) → 10°C / min (300°C) → 300°C (20 min)

[0143] Furthermore, if results suggest that the hot melt adhesive contains multiple thermoplastic resin components, dissolve the hot melt adhesive in THF and remove the solvent from the resulting soluble fraction under reduced pressure to obtain the THF-soluble component of the hot melt adhesive. Dissolve the resulting THF-soluble component of the hot melt adhesive in chloroform to prepare a sample solution with a concentration of 25 mg / mL. Inject 3.5 mL of the resulting sample solution into the following apparatus and separate fractions into components with number average molecular weights (Mn) of less than 2000, 2000 to less than 5000, 5000 to less than 10,000, 10,000 to less than 30,000, and 30,000 or more under the following conditions. Preparative GPC device: Preparative HPLC LC-980 model manufactured by Japan Analytical Industry Co., Ltd. Preparative column: JAIGEL 3H, JAIGEL 5H (manufactured by Japan Analytical Industry Co., Ltd.) Eluent: chloroform Flow rate: 3.5mL / min

[0144] To calculate the molecular weight of a sample, a molecular weight calibration curve prepared using standard polystyrene resins (for example, trade names "TSK Standard Polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-20, F-10, F-4, F-2, F-1, A-5000, A-2500, A-1000, A-500", manufactured by Tosoh Corporation) is used.

[0145] After separating each component, the solvent is distilled off under reduced pressure, the solid is separated by recrystallization from acetone, and further dried under reduced pressure in a 90 °C atmosphere for 24 hours. The above operations are repeated until about 100 mg of each component is obtained. Analyze each of the obtained components according to the identification method described above to determine the structure and content of each thermoplastic resin.

[0146] <Measurement method of Tc and Tm> Tc and Tm are measured using a differential scanning calorimeter "Q1000" (manufactured by TA Instruments). For the temperature correction of the device detection part, the melting points of indium and zinc are used, and for the heat quantity correction, the heat of fusion of indium is used. Specifically, accurately weigh 1 mg of the hot melt adhesive, place it in an aluminum pan, and use an empty aluminum pan as a reference. Heat the sample from 0 °C to 150 °C at a heating rate of 10 °C / min and maintain it at 150 °C for 5 minutes. Then, cool it from 150 °C to 0 °C at a cooling rate of 10 °C / min. The peak temperature of the peak with the highest height among the exothermic peaks generated during this cooling process is defined as Tc (°C). Subsequently, after maintaining it at 0 °C for 5 minutes, heat it from 0 °C to 150 °C at a heating rate of 10 °C / min. Among the endothermic peaks generated in the DSC curve at this time, the peak temperature of the peak with the highest height is defined as Tm (°C).

[0147] <Measurement method of glass transition temperature (Tg)> The glass transition temperature (Tg) of resins such as thermoplastic resins is measured using a differential scanning calorimeter "Q1000" (manufactured by TA Instruments). For the temperature correction of the device detection part, the melting points of indium and zinc are used, and for the heat quantity correction, the heat of fusion of indium is used. Specifically, accurately weigh 1 mg of the sample, place it in an aluminum pan, and use an empty aluminum pan as a reference. Using the modulation measurement mode, measure in the range from 0 °C to 100 °C at a heating rate of 1 °C / min and temperature modulation conditions of ±0.6 °C / 60 seconds. Since a specific heat change can be obtained during the heating process, the intersection point of the line at the midpoint between the baseline before and after the specific heat change and the differential heat curve is defined as the glass transition temperature (Tg).

[0148] <Measuring method for molecular weights Mw, Mp, Mn> The molecular weight of the THF-soluble component of a hot melt adhesive is measured by gel permeation chromatography (GPC) as follows: First, a measurement sample is dissolved in tetrahydrofuran (THF) at room temperature for 24 hours. The resulting solution is then filtered through a solvent-resistant membrane filter "Myshoridisc" (manufactured by Tosoh Corporation) with a pore size of 0.2 μm to obtain a sample solution. The sample solution is adjusted so that the concentration of the THF-soluble component is 0.8 mass%. Measurements are performed using this sample solution under the following conditions. Equipment: High-speed GPC equipment "HLC-8220GPC" [manufactured by Tosoh Corporation] Column: LF-604 (two columns, manufactured by Showa Denko K.K.) Eluent:THF Flow rate: 0.6ml / min Oven temperature: 40°C Sample injection volume: 0.020 ml

[0149] When calculating the molecular weight of the sample, standard polystyrene resins (e.g., TSK Standard Polystyrene F-850, F-450, F-288, F-128, F-8 A molecular weight calibration curve prepared using a series of chromatographs (F-0, F-40, F-20, F-10, F-4, F-2, F-1, A-5000, A-2500, A-1000, A-500, manufactured by Tosoh Corporation) is used. From the obtained molecular weight distribution, Mw, Mp, and Mn are calculated using the attached analysis software.

[0150] <Method for measuring the degree of compatibility between thermoplastic resin and crystalline material> Differential scanning calorimetry (DSC) is used to measure the degree of compatibility A and the degree of compatibility B. A resin mixture of a thermoplastic resin and a crystalline material is used as the sample.

[0151] (Production of thermoplastic resins) When a hot melt adhesive is produced by suspension polymerization, it is difficult to isolate the thermoplastic resin alone. Therefore, if these materials are available individually, they can be used. If they are not available individually, they are prepared separately. Specifically, when producing a hot melt adhesive by suspension polymerization, a resin produced using only the monomers that make up the hot melt adhesive, at the same polymerization temperature and with the same amount of polymerization initiator as the hot melt adhesive production conditions, is called a thermoplastic resin.

[0152] (Manufacturing mixed resins made by mixing thermoplastic resins and crystalline material resins) A thermoplastic resin and a crystalline material (the first crystalline material or the second crystalline material) are dissolved in 2 ml of toluene at a mass ratio of C or D, and heated as necessary to prepare a homogeneous solution. The solution is heated to 120°C in a rotary evaporator and gradually reduced in pressure to avoid bumping. The mixture is then reduced in pressure to 50 mbar and dried for 2 hours to obtain the mixed resin (mixed resin A or B).

[0153] (Measurement of degree of compatibility) The degree of compatibility A and the degree of compatibility B are measured in accordance with ASTM D3418-82 using a differential scanning calorimeter "Q1000" (manufactured by TA Instruments). The melting points of indium and zinc are used for temperature correction, and the heat of fusion of indium is used for heat quantity correction. Specifically, 2 mg of the mixed resin is weighed out and placed in an aluminum pan. An empty aluminum pan is used as a reference, and the temperature is raised at a rate of 10°C / min within the measurement range of 0°C to 100°C. The temperature is held at 100°C for 15 minutes, and then cooled at a rate of 10°C / min between 100°C and 0°C. The calorific value ΔH (J / g) of the exothermic peak in the exothermic curve during this cooling process is measured.

[0154] The degrees of compatibility A and B are calculated by the following formula. Compatibilization degree A(%)= 100-(100×ΔH(A)) / (ΔH(C)×C / 100) ···(1) ΔH(A) represents the heat generation amount (J / g) of the exothermic peak of the mixed resin A of the thermoplastic resin and the first crystalline material in differential scanning calorimetry. ΔH(C) represents the heat generation amount (J / g) of the exothermic peak of the first crystalline material in differential scanning calorimetry. C represents the mass ratio (%) of the first crystalline material in the mixed resin A. Compatibility degree B (%) = 100 - (100 × ΔH(B)) / (ΔH(C2) × D / 100) ···(2) ΔH(B) represents the heat generation amount (J / g) of the exothermic peak of the mixed resin B of the thermoplastic resin and the second crystalline material in differential scanning calorimetry. ΔH(C2) represents the heat generation amount (J / g) of the exothermic peak of the second crystalline material in differential scanning calorimetry. D represents the mass ratio (%) of the second crystalline material in the mixed resin B.

[0155] <Measurement method of THF-insoluble content> Soxhlet extraction of the hot melt adhesive for 16 hours using tetrahydrofuran (THF) The content of the THF-insoluble content not extracted by extraction is measured as follows. Weigh 1.0 g of the hot melt adhesive (W1 g), put it into a pre-weighed cylindrical filter paper (product name No. 86R (size 28 × 100 mm), manufactured by Advantec Toyo Co., Ltd.), and set it in a Soxhlet extractor. Then, extract for 16 hours using 200 ml of tetrahydrofuran (THF) as the solvent. At this time, perform the extraction at a reflux rate such that the extraction cycle of the solvent is about once every 5 minutes.

[0156] After the extraction is completed, take out the cylindrical filter paper, air-dry it, then vacuum dry it at 40 °C for 8 hours, weigh the mass of the cylindrical filter paper including the extraction residue, and subtract the mass of the cylindrical filter paper to calculate the mass (W2 g) of the extraction residue. And the content (W3 g) of the components other than the resin component is subtracted as shown in the following formula (6) to obtain the THF-insoluble content. THF-insoluble content (mass%) = {(W2 - W3) / (W1 - W3)} × 100 ···(6)

[0157] The content of components other than the resin component can be measured by known analytical means. If analysis is difficult, the content of components other than the resin component (the incineration ash content in the hot melt adhesive (W3'g)) can be estimated as follows, and the THF-insoluble content can be determined by subtracting this content. The incineration ash content in the hot melt adhesive is determined as follows: Approximately 2 g of hot melt adhesive (Wag) is weighed into a pre-weighed 30 ml porcelain crucible. The crucible is placed in an electric furnace and heated to approximately 900°C for approximately 3 hours, cooled in the electric furnace, and then cooled at room temperature in a desiccator for at least 1 hour. The mass of the crucible containing the incineration ash is weighed, and the incineration ash content (Wbg) is calculated by subtracting the mass of the crucible. The mass of the incineration ash (W3'g) in a sample W1g is then calculated using the following formula (7): W3´=W1×(Wb / Wa) (7) In this case, the THF insoluble content can be calculated by the following formula (8). THF insoluble content (mass%)= {(W2-W3´) / (W1-W3´)}×100 ···(8)

[0158] <Method for measuring viscosity at 100°C> The viscosity of a hot melt adhesive at 100°C measured using a constant-load extrusion capillary rheometer is measured as follows: A constant-load extrusion capillary rheometer, "Flow Tester CFT-500D Flow Property Evaluation Device" (Shimadzu Corporation), is used, and the measurement is carried out according to the manual that comes with the device. With this device, a constant load is applied from above the sample using a piston, while the sample filled in a cylinder is heated and melted, and the molten sample is extruded from a die at the bottom of the cylinder, and the relationship between the temperature and the amount of descent of the piston is measured.

[0159] Measurements are taken from 50°C to 200°C, and the apparent viscosity calculated at 100°C is the viscosity (Pa·s) of the hot melt adhesive at 100°C. The apparent viscosity η (Pa·s) at 100°C is calculated as follows: First, the flow rate Q (cm 3 / s) where the cross-sectional area of ​​the piston is A (cm 2 ) and the time required for the piston to descend between 0.10 mm (0.20 mm interval) above and below the position of the piston at 100°C is Δt (seconds). Q=(0.20×A) / (10×Δt) ···(9)

[0160] Then, using the obtained flow rate Q, the apparent viscosity η at 100°C is calculated using the following formula (10), where P (Pa) is the piston load, B (mm) is the diameter of the die hole, and L (mm) is the length of the die. η=(π×B 4 ×P) / (128000×L×Q) (10)

[0161] The measurement sample is a cylindrical sample with a diameter of approximately 8 mm, obtained by compressing 1.0 g of hot melt adhesive at 25°C using a tablet press (e.g., NT-100H, manufactured by NPA Systems Co., Ltd.) at 10 MPa for 60 seconds. The measurement conditions for the CFT-500D are as follows: Test mode: Temperature rising method Starting temperature: 50℃ Achieved temperature: 200℃ Measurement interval: 1.0℃ Heating rate: 4.0℃ / min Piston cross-sectional area: 1.000cm 2 Test load (piston load): 10.0 kgf (0.9807 MPa) Preheat time: 300 seconds Die hole diameter: 1.0mm Die length: 1.0mm

[0162] <Method for measuring the weight average particle size (D4) of hot melt adhesives> The weight-average particle size (D4) is calculated as follows. The measurement device used is a precision particle size distribution analyzer, "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter, Inc.), equipped with a 100 μm aperture tube and employing the narrow-pore electrical resistance method. The measurement conditions and data analysis are performed using the accompanying dedicated software, "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter, Inc.). Measurements are performed using an effective number of 25,000 measurement channels. The electrolyte solution used for the measurements is prepared by dissolving special-grade sodium chloride in ion-exchange water to a concentration of 1.0%, such as "ISOTON II" (manufactured by Beckman Coulter, Inc.).

[0163] Before performing measurements and analysis, the dedicated software should be configured as follows. In the "Change Standard Measurement Method (SOMME)" screen of the dedicated software, set the total count in control mode to 50,000 particles, the number of measurements to 1, and the Kd value to the value obtained using a "Standard Particle 10.0 μm" (Beckman Coulter, Inc.). Press the "Threshold / Noise Level Measurement Button" to automatically set the threshold and noise level. Also, set the current to 1600 μA, the gain to 2, the electrolyte to ISOTON II, and check "Flush aperture tube after measurement." In the "Pulse to Particle Size Conversion Settings" screen of the dedicated software, set the bin spacing to logarithmic particle size, the particle size bin to 256 particle size bins, and the particle size range from 2 μm to 60 μm. The specific measurement method is as follows.

[0164] (1) Pour 200.0 mL of electrolyte solution into a 250 mL round-bottom glass beaker made specifically for the Multisizer 3, set it on the sample stand, and stir the stirrer rod counterclockwise at 24 revolutions per second. Then, use the "Aperture Tube Flush" function of the dedicated software to remove any dirt and air bubbles from inside the aperture tube. (2) 30.0 mL of the electrolyte solution is placed in a 100 mL flat-bottom glass beaker. 0.3 mL of a diluted solution of "Contaminon N" (a 10% aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, anionic surfactant, and organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) diluted three times by mass with ion-exchanged water is added as a dispersant. (3) Prepare an ultrasonic disperser "Ultrasonic Dispersion System Tetra150" (manufactured by Nikkaki Bios Co., Ltd.) with an electrical output of 120 W and two built-in oscillators with an oscillation frequency of 50 kHz and a phase shift of 180 degrees. Place 3.3 L of ion-exchanged water in the ultrasonic disperser's water tank and add 2.0 mL of Contaminon N to this water tank. (4) Set the beaker (2) into the beaker fixing hole of the ultrasonic disperser and perform ultrasonic dispersion. Then, adjust the height of the beaker so that the resonance state of the electrolyte solution surface in the beaker is maximized. (5) While the electrolyte solution in the beaker in (4) is being irradiated with ultrasonic waves, 10 mg of the measurement sample is added little by little to the electrolyte solution and dispersed. The ultrasonic dispersion treatment is then continued for another 60 seconds. During the ultrasonic dispersion, the water temperature in the water tank is appropriately adjusted to be between 10°C and 40°C. (6) Using a pipette, the electrolytic solution (5) in which the toner particles have been dispersed is dropped into the round-bottom beaker (1) placed in the sample stand, and the measurement concentration is adjusted to 5%. Then, measurements are continued until the number of particles measured reaches 50,000. (7) The measurement data is analyzed using the dedicated software that comes with the device, and the weight-average particle size (D4) is calculated. Note that when the dedicated software is set to Graph / Volume %, the "Average diameter" on the "Analysis / Volume Statistics (Arithmetic Mean)" screen is the weight-average particle size (D4). [Example]

[0165] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, parts are by mass unless otherwise specified.

[0166] (Example of manufacturing crystalline material 1) A four-neck flask equipped with a thermometer, nitrogen inlet tube, stirrer, and condenser was charged with 312.9 g (1.1 mol) of stearic acid and 31 g (0.5 mol) of ethylene glycol. The mixture was reacted for 15 hours at atmospheric pressure under a nitrogen stream at 180°C while distilling off the reaction water. To 100 parts of the esterified crude product obtained by this reaction, 20 parts of toluene and 4 parts of ethanol were added. Further, a 10% aqueous potassium hydroxide solution containing potassium hydroxide in an amount equivalent to 1.5 times the acid value of the esterified crude product was added, and the mixture was stirred at 70°C for 30 minutes. After stirring, the mixture was allowed to stand for 30 minutes, and the aqueous phase (lower layer) that separated from the ester phase was removed. The esterified crude product was washed with water. This water washing process was repeated four times until the pH of the aqueous phase reached 7. The solvent was then distilled off from the washed ester phase at 180°C under reduced pressure of 1 kPa, and the mixture was filtered to obtain crystalline material 1 (ethylene glycol distearate). When the obtained crystalline material was subjected to differential scanning calorimetry, clear exothermic and endothermic peaks were observed, confirming its crystallinity. The measured melting points are shown in Table 1.

[0167] [Table 1]

[0168] (Crystalline materials 2~9) Table 1 shows the compositions and physical properties of crystalline materials 2 to 9 used in the examples and comparative examples.

[0169] <Production example of polyester resin> A reaction vessel equipped with a stirrer, thermometer, nitrogen inlet tube, dehydration tube, and pressure reducer was charged with 1.00 mol of terephthalic acid as a monomer, 0.65 mol of a 2-mol propylene oxide adduct of bisphenol A, and 0.35 mol of ethylene glycol in a molar ratio, and the mixture was heated to 130°C with stirring. Subsequently, 0.52 parts of tin di(2-ethylhexanoate) was added as an esterification catalyst per 100.00 parts of the monomer, and the mixture was heated to 200°C and subjected to condensation polymerization until the desired molecular weight was reached. Furthermore, 3.00 parts of trimellitic anhydride was added per 100.00 parts of the monomer to obtain a polyester resin. The resulting polyester resin had a peak molecular weight of 12,000 and a glass transition temperature (Tg) of 75°C.

[0170] <Hot melt adhesive 1 manufacturing example> Styrene: 75.0 parts n-Butyl acrylate: 25.0 parts Polyester resin: 4.0 parts First crystalline material: Crystalline material 1: 14.0 parts Second crystalline material: Crystalline material 6: 2.0 parts Divinylbenzene: 0.5 parts The mixture of the above materials was kept at 60°C and stirred at 500 rpm using a TK Homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to dissolve the materials uniformly, preparing a polymerizable monomer composition. Meanwhile, 850.0 parts of 0.10 mol / L Na3PO4 aqueous solution and 8.0 parts of 10% hydrochloric acid were added to a container equipped with a high-speed stirring device, Clearmix (manufactured by M Technique), and the rotation speed was adjusted to 15,000 rpm. The mixture was heated to 70°C. 127.5 parts of 1.0 mol / L CaCl2 aqueous solution was added to the container to prepare an aqueous medium containing a calcium phosphate compound.

[0171] After adding the polymerizable monomer composition to the aqueous medium, t-butylperoxycarbonyl (t-butylperoxycarbonyl) as a polymerization initiator was added. 7.0 parts of cipivalate were added, and the mixture was granulated for 10 minutes while maintaining a rotation speed of 15,000 rpm. The agitator was then changed from a high-speed agitator to a propeller agitator, and the mixture was refluxed for 5 hours at a polymerization temperature of 70°C, after which the liquid temperature was increased to 85°C and the mixture was allowed to react for an additional 2 hours. After the polymerization reaction was complete, the slurry was heated to 100°C as a heat treatment step and held there for 60 minutes. Then, as a quenching step, the mixture was quenched from 100°C to 40°C at a cooling rate of 4°C / sec through a spiral heat exchanger KSH-1 (manufactured by Kurose Co., Ltd.).

[0172] Hydrochloric acid was added to the slurry obtained after quenching to adjust the pH to 1.4, and the slurry was stirred for 1 hour to dissolve the calcium phosphate salt. The slurry was then washed with water in an amount three times the volume of the slurry, filtered, dried, and classified to obtain powder adhesive particles. Then, silica fine particles (number-average particle size of primary particles: 10 nm, BET specific surface area: 170 m) that had been hydrophobized using dimethyl silicone oil (20% by mass) were added as an external additive to 100.0 parts of the powder adhesive particles. 2 2.0 parts of PEG-100 / g was added and mixed at 3000 rpm for 15 minutes using a Mitsui Henschel mixer (manufactured by Mitsui Miike Chemical Engineering Co., Ltd.) to obtain hot melt adhesive 1 having a weight average particle size of 6.5 μm. The physical properties of the obtained hot melt adhesive are shown in Table 3.

[0173] <Production examples of hot melt adhesives 2 to 25 and comparative hot melt adhesives 1 to 4> Hot melt adhesives 2 to 25 and comparative hot melt adhesives 1 to 4 were obtained in the same manner as in the production example for hot melt adhesive 1, except that the reaction conditions, the type of crystalline material, and the amount added were changed as shown in Table 2. The physical properties of the obtained hot melt adhesives are shown in Table 3.

[0174] [Table 2]

[0175] [Table 3]

[0176] Example 1 Hot melt adhesive 1 was evaluated according to the following evaluation method. All evaluations were carried out in an environment of normal temperature and humidity (25°C / 50%RH). The paper used was GFC-081 (81.0 g / m 2 ) (Canon Marketing Japan) was used.

[0177] <Evaluation of adhesive strength> (Preparation of evaluation samples) A commercially available Canon laser beam printer, LBP712Ci, was used to prepare the evaluation samples. The software was modified so that it could operate even if all cartridges were not installed. In addition, the amount of hot melt adhesive and toner applied (mg / cm) was also measured. 2 The toner in the black cartridge of the LBP712Ci was removed, and 150 g of hot melt adhesive 1 was filled and set in the black station.

[0178] Using this printer, as shown in Figure 8, a margin of 8 cm was left at the tip, and powder adhesive was applied in an area of ​​4 cm at a rate of 0.5 mg / cm. 2 Print with a margin of 2 cm and apply a toner amount of 0.08 mg / cm2 to an area of ​​4 cm. 2 (Image A). In addition, on another piece of paper, leaving an 8cm margin at the tip, powder adhesive was applied in an area of ​​4cm at a dose of 0.5mg / cm. 2 Image A was cut into a width of 3 cm to obtain sample A. Similarly, image B was cut into a width of 3 cm to obtain sample B. The toner used was the standard toner of the LBP712Ci. I used a ner.

[0179] (Laminating evaluation samples) As shown in Figure 9, Sample A and Sample B were placed facing each other with the image surfaces facing inward, and the fixing unit temperature Tf of the external fixing unit removed from the LBP712Ci was adjusted to 200°C. The samples were then passed through with Sample A facing upward, and laminated together.

[0180] (Evaluation of adhesive strength and adhesive speed) The adhesive strength of the bonded objects was evaluated 10 seconds and 300 seconds after passing through the fixing device. A Tensilon universal testing machine RTG-1225 (manufactured by A&D Co., Ltd.) was used to evaluate adhesive strength. A parallel clamping jaw was used as the jig, and the bonded samples were set as shown in Figure 10. The horizontal axis represents the distance (mm) and the vertical axis represents the stress (N / cm) obtained when the evaluation samples were peeled off at a speed of 50 mm / min. 2 The stress per 1cm width obtained by multiplying the maximum value in the graph by 1 / 3 is the adhesive strength (N / cm 2 The larger this value, the better the adhesive strength.

[0181] <Examples 2 to 29 and Comparative Examples 1 to 4> For Examples 2 to 29 and Comparative Examples 1 to 4, the hot melt adhesive and Tf were changed as shown in Table 4, and evaluation was carried out in the same manner as in Example 1. The evaluation results are shown in Table 4. [Table 4]

[0182] As is clear from Table 4, the present invention provides an adhesive that can develop strong adhesive strength in a short time, and a method for producing such an adhesive product. [Explanation of symbols]

[0183] 1...image forming apparatus, 1e...image forming means (image forming unit), 1m...main transport path, 2...scanner unit, 3...transfer unit, 3a...transfer belt, 3b...secondary transfer inner roller, 3c...tension roller, 4...primary transfer roller, 5...transfer means (secondary transfer roller), 5n...transfer nip, 6...fixing means (first fixer), 6a...heating roller, 6b...pressure roller, 6n...fixing nip, 7n...second process unit (process cartridge), 7y, 7m, 7c...first process unit (process cartridge), 8...sheet cassette, 8a...transport roller, 9...cartridge support section, 10...apparatus main body, 12...discharge outlet (first discharge outlet), 13...guide member (first discharge tray), 13...a tray switching guide, 15...intermediate path, 19...first housing, 20...openable tray, 30...sheet processing device (post-processing unit), 31...folding means (folder), 31a...first folding roller, 31b...second folding roller, 31c...first guide roller, 31d...second guide roller, 31e...pull-in portion, 31f...guide wall, 31g...wall, 31h...end portion, 32...connection fixing means (second fixing unit), 33...switching guide, 33a...switching guide shaft portion, 33b...switching guide tip, 34...discharge unit, 34a...first discharge roller, 34b...intermediate roller, 34c...second discharge roller, 35...second discharge tray, 36, 37...connectors, 39...second housing, 51... adhesive postcard, 52... medicine bag, 51a... entire periphery of outer periphery, 51b, 52b... central fold, 52a... U-shaped area, 101...photosensitive drum, 102...charging roller, 103...cleaning member, 104n, 104y, 104m, 104c...powder containing section, 105...developing roller, 106...developer supply roller, 107...developing blade, 108...stirring member, 109...developing chamber, P...sheet, R1...first path, R2...second path, Tn...powder adhesive, Ty, Tm, Tc...printing toner, CC...photosensitive unit, DT...developing unit, q...leading edge of sheet P, r...middle, L...total length of sheet P, M...spacing, N...depth of retraction section

Claims

1. 1. A hot melt adhesive comprising a thermoplastic resin and a first crystalline material, In differential scanning calorimetry of the hot melt adhesive, Among the exothermic peaks observed during the temperature decrease process at 10°C / min after the temperature was increased to 150°C, the peak temperature of the highest peak was defined as Tc (°C), When the peak temperature of the highest endothermic peak observed in the temperature increasing process at 10°C / min after the temperature decreasing process is defined as Tm (°C), Tm-Tc is 20.0°C or higher and 70.0°C or lower, the weight average molecular weight Mw of the tetrahydrofuran soluble portion of the hot melt adhesive measured by gel permeation chromatography is 100,000 or more and 400,000 or less; the thermoplastic resin comprises a styrene-acrylic resin, the content of the styrene-acrylic resin in the thermoplastic resin is 90% by mass to 97% by mass, The styrene-acrylic resin is a styrene-based monomer; at least one unsaturated carboxylic acid ester selected from the group consisting of acrylic acid esters and methacrylic acid esters; a cross-linking agent; is a copolymer of the copolymer contains 70% by mass to 80% by mass of the monomer unit formed by polymerizing styrene; a hot melt adhesive characterized in that the amount of the structure derived from the crosslinking agent in the thermoplastic resin is 0.1% by mass to 1.0% by mass.

2. 2. The hot melt adhesive according to claim 1, wherein the degree of compatibility A of the thermoplastic resin and the first crystalline material, represented by the following formula (1), is 50% or more and 100% or less. Compatibilization degree A (%)= 100-(100×ΔH(A)) / (ΔH(C)×C / 100)...(1) ΔH(A) represents the calorific value (J / g) of the exothermic peak of the mixed resin A of the thermoplastic resin and the first crystalline material in differential scanning calorimetry. C represents the mass ratio (%) of the first crystalline material in the mixed resin A, which is 11.

9.

3. 3. The hot melt adhesive according to claim 1, wherein the content of tetrahydrofuran-insoluble matter that is not extracted by Soxhlet extraction of the hot melt adhesive for 16 hours using tetrahydrofuran is 20% by mass or more and 60% by mass or less in the hot melt adhesive.

4. the hot melt adhesive further comprises a second crystalline material; The hot melt adhesive according to any one of claims 1 to 3, wherein the degree of compatibility B of the second crystalline material and the thermoplastic resin, represented by the following formula (2), is 10% or more and less than 50%. Compatibilization degree B (%) = 100-(100×ΔH(B)) / (ΔH(C2)×D / 100)...(2) ΔH(B) represents the calorific value (J / g) of the exothermic peak of the mixed resin B of the thermoplastic resin and the second crystalline material in differential scanning calorimetry. ΔH(C2) represents the calorific value (J / g) of the exothermic peak of the second crystalline material in differential scanning calorimetry. D represents the mass ratio (%) of the second crystalline material in the mixed resin B, which is 1.

9.

5. The Tc is 20°C or higher and 60°C or lower, The hot melt adhesive according to any one of claims 1 to 4, wherein the Tm is 50 ° C. or higher and 110 ° C. or lower.

6. The hot melt adhesive according to any one of claims 1 to 5, wherein the viscosity of the hot melt adhesive at 100 ° C. measured with a constant load extrusion type capillary rheometer is 20,000 Pa s or more and 100,000 Pa s or less.

7. 7. The hot melt adhesive according to claim 1, wherein the first crystalline material is an ester wax.

8. A hot melt adhesive described in any one of claims 1 to 7, wherein the thermoplastic resin further contains a polyester resin.

9. A method for producing an adhesive product in which at least one paper is bonded via an adhesive joint using the hot melt adhesive according to any one of claims 1 to 8, a step of forming an adhesive portion by developing the adhesive portion on the paper using the hot melt adhesive and fixing the adhesive portion by heating; and a bonding step of, after forming the adhesive joint, stacking the papers so as to sandwich the formed adhesive joint and heating the stacked papers to melt the adhesive joint and bond the papers together to obtain the bonded product; the temperature Tf (°C) of the fixing unit during heating and the melting point Tm (°C) of the hot melt adhesive satisfy the relationship 70≦Tf−Tm≦200; A method for producing a bonded article, comprising:

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