Hydrolytic tack paper

Abstract

To provide a water-disintegrable tack paper in which an adhesive layer is readily water-disintegrated, when performing water disintegration with water that is not heated and pH-adjusted.SOLUTION: The problem is solved by water-disintegrable tack paper 1 characterized by having a composite paper 11 in which an inorganic pigment layer is provide on one side or two sides of a base paper and an adhesive agent layer 12 provided on one side of the composite paper 11, in which the inorganic pigment layer comprises kaolin and calcium carbonate, and the adhesive agent layer 12 has a composition containing an acrylic acid ester monomer, a functional group-containing monomer, a nonionic surfactant, a neutralizing agent, and a fatty acid soap, and calcium carbonate is contained in the range of 10 to 30 mass%.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a hydrolyzable tack paper.

Background Art

[0002] From the perspective of promoting the formation of a sustainable society and a recycling society, activities have been carried out to recycle various papers as waste paper. Regarding the recycling of papers, the Public Interest Corporation Paper Recycling Promotion Center has established waste paper standard quality specifications, and according to these specifications, it is stated that no prohibited items are allowed to be mixed into waste paper for recycling. Examples of prohibited items include adhesive sheets (Patent Document 1). Since this adhesive sheet has an adhesive element (adhesive) applied to the paper, it is classified as a prohibited item. However, if the adhesive element is removed from the paper, the paper can be recycled as waste paper.

[0003] Among adhesive sheets, in particular, the tack paper used for coated printing papers (such as pigment-coated papers and cast-coated papers) classified as high-quality waste paper is of high quality because its main raw material is high-whiteness bleached kraft pulp and has high utility value. If a technology that can reuse tack paper in deinking pulp, WP, etc. is established, it is preferable from the perspective of highly utilizing waste paper and promoting the formation of a sustainable society and a recycling society.

[0004] As one of the technologies for removing the adhesive element from paper, Patent Document 2 proposes a technology related to a water-detachable adhesive composition. The water-detachable adhesive composition has excellent adhesive physical properties, and there is little change over time in the adhesive physical properties and redispersibility even in a wet and hot environment. Also, the adhesive layer redisperses in water in an appropriate size without polluting the water quality and without adversely affecting the performance of recycled paper.

[0005] Patent Document 3 proposes an invention related to a hot-water peelable label as a technique for peeling off paper attached to a container. The hot-water peelable label has a strong adhesive force to various containers and does not peel off due to impacts or rubbing during transportation, nor does it peel off even when wet with rain. At the time of collection, it can be easily peeled off by a treatment for several tens of seconds in a washing process using hot water at approximately 60 to 80°C.

[0006] Patent Document 4 proposes a technique related to an alkali-soluble adhesive composition. The alkali-soluble adhesive composition can be used for tack paper, adhesive tapes, etc., and can be easily dissociated with alkaline water when being repulped for the purpose of resource protection.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0008] However, the technology of Patent Document 2 uses high-quality paper or kraft paper that contains as little inorganic particles for papermaking such as calcium carbonate and clay (also called kaolin) as possible as the base paper in order to change the balance over time between the adhesive force and cohesive force of the adhesive. From the perspective that calcium carbonate and clay promote the hydrolysis of the adhesive, it cannot be said that the adhesive layer is easily hydrolyzed during dissociation. The technology of Patent Document 3 is such that the adhesive is dissociated by warm water and is not dissociated by water that has not been heat-treated such as in the waste paper recycling process of a paper mill. From the perspective of recycling, it is costly to prepare warm water and is uneconomical. The technology of Patent Document 4 is dissociated by alkaline water with adjusted pH, and the used alkaline water must be neutralized and discharged as wastewater into the environment, and the wastewater treatment is complicated.

[0009] Therefore, the problem to be solved by the present invention is to provide a tack paper in which the adhesive layer is easily hydrolyzed and a method for manufacturing the same even for water that has not been heated or pH-adjusted.

Means for Solving the Problem

[0010] The present inventor has conducted intensive research, considered characteristics such as the dispersibility and hydrolysis of the adhesive layer, selected a base paper suitable for the easy hydrolysis of the adhesive layer, and thus solved the above problems. As a result, the aspects of the completed invention are as follows.

[0011] [First Aspect] A composite paper having an inorganic pigment layer provided on one side of a base paper, having an adhesive layer provided on one side of the composite paper, The base paper contains calcium carbonate in addition to pulp, the pulp is contained in an amount of 50 to 90 parts by mass per 100 parts by mass of the base paper, wherein the adhesive layer has a composition containing an acrylate monomer and a functional group-containing monomer a copolymer of a nonionic surfactant, a neutralizing agent, and a fatty acid soap, and the composite paper contains 10 to 30% by mass of calcium carbonate, characterized in that it is a hydrolyzable tack paper.

[0012] The acrylic ester monomer, which is an adhesive element, has a carboxy group in its composition. When this carboxy group chemically reacts with calcium carbonate or clay, the adhesive strength of the acrylic ester monomer may decrease. Therefore, conventionally, as disclosed in Patent Document 1, technologies related to adhesive sheets with a relatively low calcium component content have been developed.

[0013] Regarding this aspect, the inventors focused on the reactivity between the acrylic ester monomer and calcium carbonate, and obtained the finding that by adjusting the calcium carbonate content, a tack paper having a desired adhesive strength and hydrolyzability can be obtained. In this aspect, since the adhesive layer having a composition containing an acrylic ester monomer is provided on one surface of a composite paper containing a specific amount of calcium carbonate, the adhesive strength of the adhesive layer to the composite paper becomes weaker over time than the original adhesive strength of the acrylic ester monomer. Therefore, when the tack paper of this aspect is dissociated in water, the adhesive layer easily separates from the composite paper.

[0014] The tack paper of this aspect also easily hydrolyzes the adhesive layer even with water that is not heated for dissociation. This is presumably because the fatty acid soap, which is the composition of the adhesive layer, has low hydrolysis resistance and thus hydrolyzes in water.

[0015] The tack paper of this aspect also easily dissociates even when using water whose pH is not adjusted. This is because the neutralizing agent, which is the composition of the adhesive layer, has high redispersibility and thus easily hydrolyzes in water.

[0016] [Second Aspect] A composite paper having an inorganic pigment layer provided on both sides of a base paper, and an adhesive layer provided on one side of the composite paper, the base paper contains calcium carbonate in addition to pulp, the pulp is contained in an amount of 50 to 90 parts by mass per 100 parts by mass of the base paper, The adhesive layer is an acrylic ester monomer and functional group-containing monomer a copolymer of It has a composition containing a nonionic surfactant, a neutralizing agent, and a fatty acid soap, Calcium carbonate is contained in the composite paper in an amount of 10 to 30% by mass, A hydrolyzable tack paper, characterized in that.

[0017] In this aspect, since the adhesive layer is provided on one side of the composite paper, calcium carbonate reduces the adhesiveness of the adhesive layer over time, and the adhesive layer is easily separated from the composite paper during release.

[0018] [Third aspect] The thickness of the adhesive layer is 10 to 30 μm, The hydrolyzable tack paper according to the first aspect or the second aspect.

[0019] If the thickness of the adhesive layer is within the above range, the adhesive force of the surface of the adhesive layer opposite to the surface on the base paper side, that is, the surface to be attached to the object to be attached, becomes relatively strong. The reason for this is not clear, but it is presumably because the base paper side portion of the adhesive layer easily reacts with the calcium carbonate contained in the base paper, while the object to be attached side portion is at a distance in the thickness direction from the base paper and hardly reacts with the calcium carbonate.

[0020] [Fourth aspect] The adhesive force of the adhesive layer is 8 to 25 N / 25 mm, The hydrolyzable tack paper according to any one of the first to third aspects.

[0021] With the hydrolyzable tack paper of this aspect, the tack paper attached to the object to be attached does not naturally curl or peel off, and when trying to peel off by pinching the edge of the tack paper, a part of the tack paper does not remain on the object and break.

[0022] [Fifth aspect] In 100 parts by mass of the composition, the content of each component is such that the acrylate monomer is 35 to 65 parts by mass, the functional group-containing monomer is 10 to 35 parts by mass, the nonionic surfactant is 25 to 40 parts by mass, the neutralizing agent is 1 to 4 parts by mass, and the fatty acid soap is 1 to 5 parts by mass. The hydrolyzable tack paper according to any one of the first to fourth aspects.

[0023] When the acrylate monomer of the hydrolyzable tack paper is within the above content range, and the content of the functional group-containing monomer and the content of the nonionic surfactant are within the above ranges, the effect that the hydrolysis of the adhesive layer to water is prominent is achieved. Further, when the content of each of the acrylate monomer, the functional group-containing monomer, and the nonionic surfactant of the hydrolyzable tack paper is within the above range, and the content of the neutralizing agent and the content of the fatty acid soap are within the above range, the effect that it hydrolyzes extremely easily with respect to water without heating or pH adjustment is achieved.

[0024] [Sixth aspect] The composite paper has a basis weight of 70 to 100 g / m 2 and a paper thickness of 75 to 120 μm. The hydrolyzable tack paper according to any one of the first to fifth aspects.

[0025] For the hydrolyzable tack paper of this aspect, when pasting or peeling, it is not easily broken, it is easy to pick up the edge, and the effect that it is easy to handle is achieved. Further, the effect that it is easily dispersed into an appropriate size during hydrolysis and is easily hydrolyzed is achieved.

[0026] [Seventh aspect] Kaolin is contained in the composite paper in an amount of 7 to 15% by mass. The hydrolyzable tack paper according to any one of the first to sixth aspects.

[0027] For the hydrolyzable tack paper of this aspect, even when the adhesive dissolves during hydrolysis in a pulp mill's pulper equipment or the like and the remaining components remain, because it contains a specific amount of kaolin with high oil absorption. The kaolin adsorbs the remaining components of the adhesive and discharges them outside the system. Therefore, the hydrolyzable tack paper can be reused more efficiently as waste paper.

[0028] [Eighth Aspect] The inorganic pigment layer has kaolin and calcium carbonate. The hydrolyzable tack paper according to any one of the first to seventh aspects.

[0029] Since the inorganic pigment layer has kaolin and calcium carbonate, the hydrolyzable tack paper of this aspect has a reduced adhesive strength over time, and due to the action of kaolin, which is excellent in oil absorbency when the hydrolyzable tack paper is separated, the separation of the adhesive layer from the base paper is facilitated. [Advantages of the Invention]

[0030] According to the present invention, there are provided a hydrolyzable tack paper in which an adhesive layer is easily hydrolyzed when dissociation is performed with water without heating or pH adjustment, and a method for producing the same. [Brief Description of the Drawings]

[0031]

Figure 1

Figure 2

[0032] Next, modes for carrying out the invention will be described. Note that this embodiment is an example of the present invention. The scope of the present invention is not limited to the scope of this embodiment.

[0033] An embodiment according to the present invention has a composite paper 11 in which an inorganic pigment layer 20 is provided on one or both sides of a base paper 10, and an adhesive layer 12 provided on one side of the composite paper 11, and the adhesive layer 12 contains an acrylate monomer and functional group-containing monomer a copolymer of It has a composition containing a nonionic surfactant, a neutralizing agent, and a fatty acid soap, and calcium carbonate is contained in the composite paper in an amount of 10 to 20% by mass. This is the hydrolyzable tack paper 1, which is characterized by the above. Hereinafter, each part will be described in detail.

[0034] (Composite paper) The composite paper 11 is composed of a base paper 10 and an inorganic pigment layer 20.

[0035] (Inorganic pigment layer) The inorganic pigment layer 20 is a layer having an inorganic pigment. Examples of the inorganic pigment include calcium hydroxide, silica, talc, aluminum hydroxide, titanium oxide, calcium carbonate, and kaolin. In particular, it is preferable to contain calcium carbonate and kaolin because it has hydrolyzability and oil absorbency.

[0036] (Base paper) The base paper 10 is mainly composed of pulp. In addition to pulp, it contains calcium carbonate and may also contain kaolin.

[0037] The pulp can be contained in an amount of 50 to 90 parts by mass, preferably 70 to 80 parts by mass, per 100 parts by mass of the base paper. Examples of the pulp include natural pulp, synthetic pulp, and the like. The natural pulp is not particularly limited, and examples thereof include pulp fibers obtained from wastepaper pulp (DIP), chemical pulp, mechanical pulp, and non-wood pulp such as kenaf, bagasse, hemp, and cotton. Examples of the chemical pulp include hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), softwood unbleached kraft pulp (NUKP), hardwood sulfite pulp, softwood sulfite pulp, and the like. Examples of the mechanical pulp include thermomechanical pulp (TMP), pressure refined softwood kraft pulp, refiner ground pulp, ground pulp (GP), and the like. Examples of the wastepaper pulp include deinked wastepaper pulp, deinked and defatted wastepaper pulp (DIP), deinked, defatted, and bleached wastepaper pulp, and the like, which are produced from waste tea paper, kraft envelope wastepaper, magazine wastepaper, newspaper wastepaper, leaflet wastepaper, office wastepaper, corrugated cardboard wastepaper, high-quality wastepaper, Kent wastepaper, imitation wastepaper, deed wastepaper, and the like. Among these, bleached kraft pulps such as hardwood bleached kraft pulp and softwood bleached kraft pulp are used as printing coated papers such as pigment-coated paper and cast-coated paper, and can be suitably used for the base paper 10 of the hydrolytic tack paper 1. These pulps can be used alone or in combination of two or more.

[0038] The base paper 10 contains calcium carbonate. The adhesive force during hydrolysis and the adhesive force over time of the adhesive layer 12 can be adjusted by the calcium carbonate content. Although the mechanism of this is not clear, it is generally considered as follows. The adhesive layer 12 provided on one side of the composite paper 11 contains an acrylate monomer, and the carboxy groups constituting this acrylate monomer chemically react with calcium ions and form crosslinks with other acrylate monomers. The formation of this crosslink causes the adhesive force of the adhesive layer 12 to decrease over time and become suitable for hydrolysis. Therefore, for example, in the hydrolyzable tack paper 1 with a higher calcium carbonate content, when the hydrolyzable tack paper 1 is dissociated with water, the hydrolysis of the adhesive layer 12 is promoted and the adhesive layer 12 is more likely to separate from the composite paper 11.

[0039] Although the adhesive layer 12 is provided on one side of the composite paper 11, it can be provided whether the one side of the composite paper 11 has the inorganic pigment layer 20 or does not have the inorganic pigment layer 20.

[0040] The calcium carbonate content is preferably 10 to 30% by mass, more preferably 11 to 20% by mass, and still more preferably 12 to 18% by mass in the composite paper 11. If the calcium carbonate content is less than 10% by mass, when the hydrolyzable tack paper 1 is dissociated with water, the adhesive layer 12 is difficult to separate from the composite paper 11 and may become an adhesive foreign matter when recycling waste paper. If the content exceeds 30% by mass, when stored for a long time, the adhesive force of the hydrolyzable tack paper 1 may decrease too much. For example, the calcium carbonate content can be calculated by calculating the composition ratio of the composite paper. Also, in the elemental analysis of the composite paper by an X-ray microanalyzer, the calcium carbonate content can be calculated based on the calcium ratio.

[0041] Kaolin is a clay mineral used for internal addition and external addition (for surface coating). When classifying kaolin based on particle size and shape, it can be classified into fine kaolin, primary kaolin, secondary kaolin, delaminated kaolin, etc. In this embodiment, any of these kaolins can be used without particular limitation, and among them, fine kaolin can be preferably used. For example, the content of kaolin can be calculated by calculating the composition ratio of the composite paper. Also, in the elemental analysis of the composite paper using an X-ray microanalyzer, the content of kaolin can be calculated based on the silica and aluminum ratios.

[0042] Due to the oil-absorbing property of kaolin, the oily adhesive is partially adsorbed by kaolin. When kaolin is contained in the base paper 10 of the hydrolyzable tack paper 1, for example, the kaolin near the surface of the base paper where the adhesive layer 12 is provided directly or indirectly adsorbs the adhesive forming the adhesive layer 12. When this hydrolyzable tack paper 1 is separated with water, kaolin remains adsorbed with the adhesive and separates from the base paper 10, so the adhesive can also be easily separated from the base paper 10.

[0043] Kaolin only needs to be contained in the base paper 10 or the composite paper 11, and the content rate contained in the composite paper 11 only needs to exceed 0.1% by mass, but preferably 7 - 15% by mass, more preferably 8 - 15% by mass, and particularly preferably 10 - 15% by mass. Even if the content rate exceeds 15% by mass, the oil absorption performance of kaolin reaches its peak and no further effects can be expected.

[0044] Regarding the composite paper 11, the basis weight and paper thickness are not particularly limited, but it is preferable that the basis weight is 70 - 100 g / m 2 , and the paper thickness is 75 - 120 μm. It is more preferable that the basis weight is 75 - 95 g / m 2 , and the paper thickness is 80 - 110 μm. If the basis weight is less than 70 g / m 2 , or the paper thickness is less than 75 μm, the strength of the hydrolyzable tack paper 1 is weak and there is a risk of tearing. If the basis weight is 100 g / m 2When the basis weight is super or the paper thickness exceeds 120 μm, if the object to be pasted has a curved surface shape, the pasted state may not be maintained, and a part of the hydrolyzable tack paper 1 may be easily curled. Also, it may not be possible to dissociate into an appropriate size during hydrolysis, and the dispersibility may deteriorate. The basis weight of the composite paper 11 is a value measured in accordance with JIS P8124 (2011). The paper thickness of the composite paper 11 is a value measured in accordance with JIS P8118 (2014).

[0045] The base paper 10 can be manufactured by papermaking using the above raw materials. Papermaking can be performed using a paper machine such as a fourdrinier paper machine, a twin-wire paper machine, an on-top paper machine, a hybrid paper machine, or a cylinder paper machine. When papermaking, additives can be added to the pulp. As additives to be added, for example, paper strength enhancers such as polyvinyl alcohol-based polymer compounds, urea resins, melamine resins, and starches, chemical fixing agents such as sulfuric acid bands, sizing agents such as cationized starch, polyethyleneimine, polyethylene oxide, rosin size, alkyl ketene dimer (AKD), alkenyl succinic anhydride (ASA), water resistance agents such as polyamides, polyamines, and epichlorohydrin, defoaming agents, fillers such as talc, dyes, color pigments, antibacterial agents, ultraviolet absorbers, pH adjusters, etc. can be used. Note that photographic paper or film may be used for the base paper 10.

[0046] The density of the composite paper 11 is preferably 0.95 to 1.20 g / cm 3 and more preferably 1.00 to 1.15 g / cm 3 If the density of the composite paper 11 is less than 0.95 g / cm 3 the surface irregularities of the composite paper 11 will increase, and it may be difficult to form the adhesive layer 12 uniformly. If the density of the composite paper 11 is 1.20 g / cm 3If it exceeds this value, the cushioning property (elastic force) of the base paper becomes insufficient, and the hydrolyzable tack paper 1 does not bend flexibly, so it may be difficult to adhere neatly to the surface to be pasted. The tightness of the composite paper 11 can be adjusted using known devices such as a machine calender, a super calender, a heat calender, etc. The tightness of the composite paper 11 is a value measured in accordance with JIS P 8118 (2014).

[0047] (Adhesive layer) The adhesive layer 12 is formed by coating the composite paper 11 with an adhesive, has an adhesive force, and adheres to the object to be pasted by the adhesive force. When the hydrolyzable tack paper 1 is dissociated in water, the adhesive layer 12 easily separates from the composite paper 11. The adhesive layer 12 contains the following composition, specifically, an acrylate monomer, a functional group-containing monomer, a nonionic surfactant, a fatty acid soap, and further contains a neutralizing agent.

[0048] The acrylate monomer is the main component of the composition of the adhesive layer 12. Examples of the acrylate monomer include (meth)acrylic acid alkyl esters, specifically butyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, etc. The number of carbon atoms in the alkyl group of the (meth)acrylic acid alkyl ester is not particularly limited, but it is preferably 4 to 12 because it is easy to adjust to the desired adhesive force. When the content of the acrylate monomer per 100 parts by mass of the composition of the adhesive layer 12 is preferably 35 to 65 parts by mass, more preferably 40 to 60 parts by mass, and still more preferably 45 to 55 parts by mass, the adhesive force is preferably exhibited.

[0049] The functional group-containing monomer has the effect of imparting dispersibility in water to the adhesive layer 12. When the functional group forming the functional group-containing monomer is particularly a carboxyl group or an alkoxy group, the dispersibility of the adhesive layer 12 in water is preferably high. As the functional group-containing monomer, one or more selected from acrylic acid, methacrylic acid, acrylic acid dimer, caprolactane adduct of (meth)acrylic acid, alkoxy acrylates such as methoxy acrylate, ethoxy acrylate, butoxy acrylate, and acrylic acid esters such as itaconic acid can be used in combination. When the acrylic acid ester monomer is contained in an amount of 35 to 65 parts by mass per 100 parts by mass of the composition of the adhesive layer 12, the functional group-containing monomer is preferably contained at a content of 10 to 35 parts by mass, more preferably 20 to 30 parts by mass, and the dispersibility of the adhesive layer 12 in water is enhanced, which is preferable. The functional group-containing monomer If the content is less than 10 parts by mass, the content of the functional group-containing monomer with respect to the acrylic acid ester monomer is small, and the dispersibility of the adhesive layer 12 in water may be poor. The functional group-containing monomer If the content exceeds 35 parts by mass, the content of the functional group-containing monomer with respect to the acrylic acid ester monomer is somewhat excessive, the glass transition temperature (Tg) of the polymer becomes high, the adhesion characteristics at low temperatures deteriorate, etc., and the effect of enhancing the dispersibility of the adhesive layer 12 in water reaches a plateau, which is not preferable.

[0050] The nonionic surfactant emulsifies the adhesive layer 12 separated from the composite paper 11 when the hydrolyzable tack paper 1 is dissociated in water to form fine particles. Due to the emulsifying action of the nonionic surfactant, the adhesive layer 12 is easily separated from the composite paper 11 during dissociation. In addition, since the aggregation of the fine particles is suppressed by the emulsifying action of the nonionic surfactant, the problems caused by the adhesion of the aggregated adhesive to the dissociation machine and other equipment can be suppressed. Furthermore, it is preferable because the emulsification of the lipophilic adhesive is promoted.

[0051] As the nonionic surfactant, for example, one or more selected from polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene monolaurate, polyoxyethylene monooleate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monooleate, etc. can be used in combination.

[0052] When the acrylate monomer is contained in an amount of 35 to 65 parts by mass per 100 parts by mass of the composition of the pressure-sensitive adhesive layer 12, it is preferable that the nonionic surfactant is contained at a content rate of 20 to 40 parts by mass, more preferably 25 to 35 parts by mass. Due to the emulsifying action, the pressure-sensitive adhesive layer 12 separated from the composite paper 11 becomes fine particles and is dispersed in water, which is preferable. If the content rate of the nonionic surfactant is less than 35 parts by mass, there is a possibility that emulsification may not be sufficiently carried out. If the content rate of the nonionic surfactant exceeds 65 parts by mass, the content rate of the nonionic surfactant with respect to the acrylate monomer is somewhat excessive, and the effect by emulsification reaches a peak and is uneconomical.

[0053] Fatty acid soap can be added to the composition of the pressure-sensitive adhesive layer 12 for the purpose of suppressing the fluffing of the pulp caused by dissociation and preventing the deterioration of the pulp quality. As the fatty acid soap, one or a combination of two selected from sodium salts and potassium salts of palmitic acid, stearic acid, oleic acid, etc. can be used. The content rate of the fatty acid soap per 100 parts by mass of the composition of the pressure-sensitive adhesive layer 12 is preferably 1 to 10 parts by mass, more preferably 3 to 7 parts by mass.

[0054] The neutralizing agent is used to react with some or all of the carboxyl groups of the acrylate monomer to impart hydrophilicity or water solubility to the acrylate monomer. As the neutralizing agent, basic compounds can be used, and amines and substituted amines can preferably be used. Specifically, ammonia, ammonium salts showing alkalinity, primary amines such as monoethylamine and monoethanolamine, secondary amines such as diethylamine and diethanolamine, tertiary amines such as triethylamine, triethanolamine, N,N,N'-trimethylethylenediamine, N-methyldiethanolamine, N,N-diethylhydroxylamine, N,N-dimethylformamide diethyl acetal, amino compounds having a plurality of N in one molecule such as diamine and polyethyleneimine, cyclic amino compounds such as pyridine, etc., one or two selected from organic amino compounds showing alkalinity can be used in combination.

[0055] The content of the neutralizing agent per 100 parts by mass of the composition of the adhesive layer 12 is preferably 1 to 10 parts by mass, more preferably 3 to 7 parts by mass, so that the effect of adding the neutralizing agent is exhibited, which is preferable.

[0056] The adhesive layer 12 provided on one surface of the composite paper 11 preferably has a thickness of 10 to 30 μm, more preferably 15 to 25 μm. If the thickness is less than 10 μm, there is a possibility that the desired adhesive force cannot be imparted. If it exceeds 30 μm, the concentration of the adhesive layer 12 in the release liquid is high, and there is a possibility that the adhesive layer 12 separated from the composite paper 11 due to release adheres to the composite paper 11 again.

[0057] The adhesive force of the adhesive layer 12 is preferably 8 to 25 N / 25 mm, more preferably 10 to 15 N / 25 mm. If the adhesive force is less than 8 N / 25 mm, even when pasted on an object to be pasted, it is likely to curl or peel off. If the adhesive force exceeds 25 N / 25 mm, there is a possibility that the hydrolytic tack paper 1 will tear when trying to peel it off.

[0058] (Release paper) In order to protect the surface of the adhesive layer 12 provided on the composite paper 11, a peelable release paper 13 that covers the surface can be provided. The release paper 13 can be, for example, one provided with a release agent, a pigment, and a binder on one or both surfaces of a sheet. Here, the surface of the adhesive layer 12 refers to the surface on the side opposite to the surface of the adhesive layer 12 facing the composite paper 11.

[0059] Examples of the sheet include fine paper, medium paper, sized or unsized kraft paper (acidic paper or neutral paper) used for packaging, and pure white roll paper.

[0060] As the pigment provided on the release paper 13, those containing a flat pigment or a non-flat pigment can be used. The flat pigment and the non-flat pigment can be distinguished by the aspect ratio. For example, those with an aspect ratio of 5 or more are flat pigments, and those with an aspect ratio of less than 5 are non-flat pigments. The aspect ratio refers to the value obtained by dividing the particle diameter (Feret diameter) of the pigment by its thickness, and can be determined by the average value of 20 arbitrarily extracted particles observed under magnification with an electron microscope. When a flat pigment is provided on the sheet, when a release agent is applied to the sheet coated with the flat pigment, penetration of the release agent into the sheet can be suppressed. The release agent refers to, for example, one containing a silicone resin diluted with an organic solvent such as toluene.

[0061] Examples of the flat pigment provided on the release paper 13 include those composed of one or a combination of two or more selected from clay (clay mineral), mica group, brittle mica group, pyrophyllite, talc, smectite, vermiculite, chlorite, septarian chlorite, serpentine, stilpnomelane, montmorillonite, etc., and clay is preferred. Examples of the non-flat pigment include those composed of one or a combination of two or more selected from calcium carbonate, white carbon, titanium oxide, aluminum hydroxide, etc.

[0062] As the binder provided on the release paper 13, those used when forming a coating layer on coated paper, such as latex made of synthetic resin, can be used. Examples of the latex include those composed of one or more combinations selected from styrene-butadiene copolymers, acrylic-styrene copolymers, methacrylate-butadiene copolymers, acrylonitrile-butadiene copolymers, acrylic copolymers, polyester copolymers, and polyurethane copolymers. These may include a water-soluble polymer compound with a bond. Examples of the water-soluble polymer compound include polyvinyl alcohol.

[0063] The hydrolyzable tacky paper 1 of the present embodiment hydrolyzes in water without heating or pH adjustment. "Water without heating" refers to water that has not been subjected to a treatment to increase the temperature with equipment such as steam or a heater. Also, water that is 40°C or higher even without a treatment to increase the temperature is not included in "water without heating". "Water without pH adjustment" refers to water to which nothing has been added to change the pH to acidic or alkaline, and can also be said to be water with a pH in the range of 6 to 8.

Example

[0064] (Composite paper of Example 1) Calcium carbonate was added as a filler to a raw material composed of hardwood kraft pulp and softwood kraft pulp (ash content rate 5.0%), and paper was made with an on-top type paper machine to obtain a base paper of 61.0 g / m 2 Next, a coating composition (50 parts by mass of kaolin, 50 parts by mass of calcium carbonate pigment (total 100 parts by mass), 7 parts by mass of latex, and 1.5 parts by mass of starch) was applied to one side of the obtained base paper to a dry weight of 14.0 g / m 2 to obtain a composite paper provided with an inorganic pigment layer. Further, a cast coating composition (12 parts by mass of an organic pigment, 30 parts by mass of a binder such as casein, and a total of 5 parts by mass of a release agent and calcium formate) was applied to the outer surface of the inorganic pigment layer to a dry weight of 14.0 g / m 2Coated and mirror-finished composite paper (cast-coated paper, 89.0 g / m 2 ) was produced. Here, the composition ratio in the composite paper is pulp and other components: calcium carbonate: kaolin = 74% by mass: 14% by mass: 12% by mass.

[0065] (Composite papers of Examples 2 and 3, and Comparative Examples 1, 2, 4, and 5) By changing the composition ratio of the composite paper obtained in Example 1, composite papers of Examples 2 and 3, and Comparative Examples 1, 2, 4, and 5 were obtained.

[0066] (Composite paper of Example 4) Calcium carbonate was added as a filler to a raw material composed of hardwood kraft pulp and softwood kraft pulp (ash content rate 8.0%), and paper was made on an on-top type paper machine to obtain a base paper of 60.0 g / m 2 . Next, a coating composition (7 parts by mass of latex and 1.5 parts by mass of starch with respect to 100 parts by mass of a pigment composed of 30 parts by mass of kaolin and 70 parts by mass of calcium carbonate) was coated on both sides of the obtained base paper to be 25.0 g / m 2 in absolute dry weight, and a composite paper (coated paper, 89.0 g / m 2 ) provided with an inorganic pigment layer was produced. Here, the composition ratio in the composite paper is pulp and other components: calcium carbonate: kaolin = 68% by mass: 25% by mass: 7% by mass.

[0067] (Composite papers of Comparative Examples 3 and 6) By changing the composition ratio of the composite paper (coated paper) obtained in Example 4, composite papers of Comparative Examples 3 and 6 were obtained.

[0068] Table 1 shows the evaluation of physical properties, composition, and disintegration properties of Examples and Comparative Examples.

[0069]

Table 1

[0070] (Adhesive) Adhesive A was used as the adhesive in Examples 1 to 4. The composition of Adhesive A is acrylic ester monomer 50 mass% and 15 mass% of the functional group-containing monomer a copolymer of , 30 mass% of the surfactant, 2 mass% of the neutralizing agent, and 3 mass% of the fatty acid soap. Adhesive B was used as the adhesive for Comparative Examples 1 to 3. The composition of Adhesive B is acrylic ester monomer 30 mass% and 45 mass% of the functional group-containing monomer a copolymer of , 20 mass% of the surfactant, and 5 mass% of the neutralizing agent. Adhesive C was used as the adhesive for Comparative Examples 4 to 6. The composition of Adhesive C is acrylic ester monomer 70 mass% and 15 mass% of the functional group-containing monomer a copolymer of , and 15 mass% of the surfactant.

[0071] (Release property) The following operations were performed to evaluate the release property. (1) The hydrolyzable tack papers of Examples 1 to 4 and Comparative Examples 1 to 6 were each cut into 5×5 cm sizes and 100 g was collected. (2) The hydrolyzable tack paper cut into pieces was put into 2400 mL of tap water at 15°C and mixed, and adjusted to a concentration of 4% by weight, and dissociated for 50 minutes with a standard dissociator specified in Appendix A of JIS P 8220 to obtain a dissociation solution. (3) 50 g of the solid content in the dissociation solution was collected in two portions, each diluted with water to a concentration of 4% by weight, and further dissociated for 10 minutes to obtain two dissociation raw materials. (4) The dissociation raw materials were screened with a 6-cut flat screen for 7 minutes (flow rate 10 L / min), and then the screen residue was collected. (5) After drying the screen residue at 105°C for 1 hour, the weight (absolute dry weight) was measured, and the release property was evaluated according to the following evaluation criteria. Also, the tap water was changed to warm water (40 to 50°C) and a weak alkaline aqueous solution (pH 8), and the release property was evaluated according to the same evaluation criteria. Here, the residue rate is a value obtained by the following calculation formula. [Equation 1] Residue rate (%) = [weight (g) of the screen residue collected in the above operation (4) / input weight (g) of the hydrolyzable tack paper input in the above (2)] × 100

[0072] The evaluation criteria are shown below. ◎: The residue rate is less than 1.0% and the releasability is good. ○: The residue rate is more than 1.0% and less than 5.0%, the releasability is good, but some adhesive foreign matters remain. ×: The residue rate exceeds 5.0%, the releasability is poor, and the adhesive foreign matters are prominent.

[0073] (Adhesive force) For the examples and comparative examples, the adhesive force was measured. The adhesive force was measured in accordance with the test method specified in JIS Z 0237 (2009). The measurement conditions are as follows. Peel: 180° peel (peel speed 300 mm / min) Adherend: SUS304 Width of test piece: 25 mm Laminating: The test piece attached to the adherend under the conditions of 23°C and 50% RH was laminated by reciprocating once with a 2 kg roller. The tensile test was carried out 1 day after laminating the test piece.

Industrial Applicability

[0074] The present invention can be used as a hydrolyzable tack paper.

Claims

1. A composite paper having an inorganic pigment layer provided on one side of a base paper, having an adhesive layer provided on one side of the composite paper, wherein the base paper contains calcium carbonate in addition to pulp, the pulp is contained in an amount of 50 to 90 parts by mass per 100 parts by mass of the base paper, the adhesive layer has a composition containing a copolymer of an acrylate monomer and a functional group-containing monomer, a nonionic surfactant, a neutralizing agent, and a fatty acid soap, calcium carbonate is contained in the composite paper in an amount of 10 to 30% by mass, characterized in that it is a hydrolyzable tack paper.

2. A composite paper having an inorganic pigment layer provided on both sides of a base paper, and an adhesive layer provided on one side of the composite paper, wherein the base paper contains calcium carbonate in addition to pulp, the pulp is contained in an amount of 50 to 90 parts by mass per 100 parts by mass of the base paper, the adhesive layer has a composition containing a copolymer of an acrylate monomer and a functional group-containing monomer, a nonionic surfactant, a neutralizing agent, and a fatty acid soap, calcium carbonate is contained in the composite paper in an amount of 10 to 30% by mass, characterized in that it is a hydrolyzable tack paper.

3. Kaolin is contained in the composite paper in an amount of 10 to 15% by mass, The hydrolyzable tack paper according to claim 1 or claim 2.

4. The thickness of the adhesive layer is 10 to 30 μm, The hydrolyzable tack paper according to any one of claims 1 to 3.

5. The adhesive strength of the adhesive layer is 8 to 25 N / 25 mm, The hydrolyzable tack paper according to any one of claims 1 to 4.

6. The composition of the composition is a copolymer of 35 to 65 parts by mass of an acrylate monomer and 10 to 35 parts by mass of a functional group-containing monomer, 25 to 40 parts by mass of a nonionic surfactant, 1 to 4 parts by mass of a neutralizing agent, and 1 to 5 parts by mass of a fatty acid soap, The hydrolyzable tack paper according to any one of claims 1 to 5.

7. The composite paper has a basis weight of 70 to 100 g / m ２ and a paper thickness of 75 to 120 μm. The hydrolyzable tack paper according to any one of claims 1 to 6.

8. The inorganic pigment layer has kaolin and calcium carbonate, The hydrolyzable tack paper according to any one of claims 1 to 7.

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