JP2018070837A - Manufacturing method of adhered article detachment promoter and molten pulp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhered article detachment promoter capable of promoting detachment of an adhered article.SOLUTION: An adhered article detachment promoter containing phosphonic acid (salt) is used. It is preferable to further contain a surfactant and the content of the surfactant is preferably 1 to 99 pts.wt. based on 100 pts.wt. of the phosphonic acid (salt). The surfactant is preferably a polyoxyalkylene compound. The polyoxyalkylene compound is preferably a compound represented by the general formula (1). R1[(-OA)n-OR2]m (1), where R1 is a hydrogen atom, an alkyl group, an alkenyl group, a reaction residue excluding m hydroxyl groups from polyalcohol, R2 is a hydrogen atom, an alkyl group, an alkenyl group, OA is an oxyalkylene group, n is 2 to 100 and m is 1 to 6.SELECTED DRAWING: None

Description

  The present invention relates to a pressure-sensitive adhesive release accelerator and a method for producing a dissolving pulp.

  As a method for producing a dissolving pulp using a lignocellulosic material as a raw material, a prehydrolysis-kraft cooking method is known (Patent Document 1 and Patent Document 2).

Japanese Patent No. 2984798 Japanese Patent No. 5712754

In the pre-hydrolysis step of the pre-hydrolysis-kraft cooking method, a sticky substance derived from lignocellulosic material is generated and adheres to production equipment such as a transfer pump, piping, and a screen, thereby preventing stable operation. There is a problem that.
An object of the present invention is to provide a pressure-sensitive adhesive peeling accelerator that can promote the peeling of a pressure-sensitive adhesive.

  The feature of the pressure-sensitive adhesive peeling accelerator of the present invention is that it contains phosphonic acid (salt).

  The characteristic of the manufacturing method of the dissolving pulp of this invention makes a summary the point including the process of hydrolyzing a lignocellulosic substance in presence of said adhesive substance peeling accelerator.

  The pressure-sensitive adhesive peeling accelerator of the present invention can promote peeling of pressure-sensitive adhesives. Therefore, when the pressure-sensitive adhesive peeling accelerator of the present invention is used, adhesion of the pressure-sensitive adhesive can be efficiently suppressed.

  Since the manufacturing method of the dissolving pulp of this invention uses said adhesive substance peeling, it can suppress the adhesion of the adhesive substance to manufacturing equipment efficiently. Therefore, according to the manufacturing method of the dissolving pulp of this invention, the stable operation of dissolving pulp manufacture is realizable, and productivity (namely, production efficiency) can be improved significantly.

  Phosphonic acid (salt) means phosphonic acid or phosphonate, and both organic phosphonic acid (salt) and inorganic phosphonic acid (salt) can be used.

  Examples of the inorganic phosphonic acid (salt) include phosphonic acid, disodium phosphonate, dipotassium phosphonate, and diammonium phosphonate.

  As organic phosphonic acid (salt), monophosphonic acid (salt) {decylphosphonic acid, sodium decylphosphonate, ammonium decylphosphonate, 2-phosphonobutane-1,2,4-tricarboxylic acid, 2-phosphonobutane-1,2, Sodium 4-tricarboxylate, pentasodium 2-phosphonobutane-1,2,4-tricarboxylate and tripotassium 2-phosphonobutane-1,2,4-tricarboxylate}, bisphosphonic acid (salt) {1-hydroxyethylidene-1 , 1-diphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonate sodium, 1-hydroxyethylidene-1,1-diphosphonate tetrasodium, 1-hydroxyethylidene-1,1-diphosphonate tripotassium, alendronate , Sodium alendronate, ammonium alendronate, Diphosphonic acid and sodium methylenediphosphonate}, trisphosphonic acid (salt) {nitrilotris (methylenephosphonic acid), nitrilotris (methylenephosphonic acid) sodium, nitrilotris (methylenephosphonic acid) ammonium, nitrilotris (methylenephosphonic Acid) pentasodium and nitrilotris (methylenephosphonic acid) tripotassium etc.}, tetrakisphosphonic acid (salt) {N, N, N ′, N-tetrakis (phosphonomethyl) ethylenediamine, N, N, N ′, N-tetrakis ( Phosphonomethyl) ethylenediamineammonium, N, N, N ′, N-tetrakis (phosphonomethyl) ethylenediaminetetrasodium and N, N, N ′, N-tetrakis (phosphonomethyl) ethylenediamine octapotassium etc.}.

  Of these, organic phosphonic acids are preferred, and monophosphonic acid and bisphosphonic acid are more preferred.

  Phosphonic acid (salt) may be contained alone or in combination.

  It is preferable that a surfactant is included in the pressure-sensitive adhesive release accelerator of the present invention.

  As the surfactant, a known surfactant is included, and examples thereof include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants.

  As the nonionic surfactant, polyoxyalkylene compounds and polyhydric alcohol fatty acid esters can be used.

  Examples of the polyoxyalkylene compound include compounds represented by the general formula (1).

 R1 [(-OA) n-OR2] m (1)

  R1 is a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms, or a reaction residue obtained by removing m hydroxyl groups from a polyhydric alcohol, R2 is a hydrogen atom, an alkyl having 1 to 30 carbon atoms A group or an alkenyl group having 2 to 30 carbon atoms, OA represents an oxyalkylene group having 2 to 4 carbon atoms, n represents an integer of 2 to 100, and m represents an integer of 1 to 6.

  Among the reaction residues (R1) obtained by removing m hydroxyl groups from a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms or a polyhydric alcohol, an alkyl group having 1 to 30 carbon atoms A straight chain alkyl group, a branched chain alkyl group or the like can be used.

  Linear alkyl groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, icosyl, henicosyl , Docosyl, tricosyl, tetracosyl, heptacosyl, hexacosyl, heptacosyl, octacosyl, nonacosyl and triaconsil.

  Examples of the branched alkyl group include isopropyl, isobutyl, t-butyl, isopentyl, neopentyl, isohexyl, isotridecyl, isotetradecyl, isooctadecyl, isotriacontyl, 2-ethylhexyl, 8-methyl-1-nonyl, 2 -Propylheptyl, 2-butyloctyl, 2-hexyldecyl, 2-octyldodecyl, 2-decyltetradecyl, 2-dodecylhexyl, 2-dodecylhexadecyl, 3,5,5-trimethylhexyl and 3, Examples include 7,11-trimethyldodecyl.

  Moreover, a straight chain alkenyl group, a branched alkenyl group, etc. can be used as a C2-C30 alkenyl group among R1.

  Linear alkenyl groups include vinyl, allyl, propenyl, butenyl, pentenyl, heptenyl, octenyl, notynyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, octadecenyl, nonadecenyl, icocenyl, hexocenyl, hexocenyl, , Tetracocenyl, pentacocenyl, hexaxenyl, heptacocenyl, octacocenyl, triaconenyl and the like.

  Examples of the branched alkenyl group include isobutenyl, isopentenyl, neopentenyl, isohexenyl, isotridecenyl, isooctadecenyl and isotriacontenyl.

  Among R1, polyhydric alcohols that can constitute a reaction residue obtained by removing m hydroxyl groups from polyhydric alcohols are dihydric alcohols (aliphatic diols, alicyclic diols and aromatic diols), and trihydric alcohols. (Aliphatic triol, alicyclic triol and aromatic triol), tetravalent alcohol (aliphatic tetraol, alicyclic tetraol and aromatic tetraol), pentavalent alcohol (aliphatic pentaol, alicyclic pentaol) And aromatic pentaols) and hexahydric alcohols (aliphatic hexaols, alicyclic hexaols and aromatic hexaols).

  Aliphatic diols include aliphatic diols having 2 to 18 carbon atoms, such as ethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, diethylpropanediol, hydroxyoctadecenyl alcohol, diethylene glycol, and triethylene. Examples include glycol, tetraethylene glycol, trimethylpentanediol, and di (hydroxyethyl) thioether.

  Examples of the alicyclic diol include alicyclic diols having 6 to 15 carbon atoms, such as 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 4,4′-dihydroxydicyclohexane and dihydroxydicyclohexyl. Examples include dimethylmethane.

  The aromatic diol includes aromatic diols having 6 to 15 carbon atoms, and examples thereof include catechol, hydroquinone, bisphenol A, bisphenol F, bisphenol S, and 1,4-dihydroxynaphthalene.

  Aliphatic triols include aliphatic triols having 3 to 11 carbon atoms, and examples include glycerin, trimethylolethane, trimethylolpropane, trimethyloloctane, and hexanetriol.

  The alicyclic triol includes alicyclic triols having 6 to 15 carbon atoms, and examples thereof include trihydroxycyclohexane, trihydroxydicyclohexane, and trihydroxydicyclohexyldimethylmethane.

  The aromatic triol includes an aromatic triol having 6 to 15 carbon atoms, and examples thereof include trihydroxybenzene, trihydroxybiphenyl, and trihydroxydiphenyldimethylmethane.

  Aliphatic tetraols include aliphatic tetraols having 5 to 12 carbon atoms, and include diglycerin, pentaerythritol, trimethylolpentane, and ditrimethylolpropane.

  The alicyclic tetraol includes an alicyclic tetraol having 6 to 15 carbon atoms, and examples thereof include tetrahydroxycyclohexane, tetrahydroxydicyclohexane, sorbitan, and tetrahydroxydicyclohexyldimethylmethane.

  The aromatic tetraol includes an aromatic tetraol having 6 to 15 carbon atoms, and examples thereof include tetrahydroxybenzene, tetrahydroxybiphenyl, and tetrahydroxydiphenyldimethylmethane.

  Aliphatic pentaols include aliphatic pentaols having 5 to 9 carbon atoms such as triglycerin and xylitol.

  The alicyclic pentaol includes alicyclic pentaol having 6 to 12 carbon atoms, such as pentahydroxycyclohexane, pentahydroxydicyclohexane, pentahydroxydicyclohexyldimethylmethane, and hydroquinone-β-D-glucoside. Etc.

  The aromatic pentaol includes aromatic pentaol having 6 to 15 carbon atoms, and examples thereof include pentahydroxybenzene, pentahydroxybiphenyl, and pentahydroxydiphenyldimethylmethane.

  Aliphatic hexaols include C6-C12 aliphatic hexaols, and include sorbitol, tetraglycerin, dipentaerythritol, and the like.

  Examples of the alicyclic hexaol include alicyclic hexaol having 6 to 15 carbon atoms, and examples thereof include hexahydroxycyclohexane, hexahydroxydicyclohexane, and hexahydroxydicyclohexyldimethylmethane.

  The aromatic hexaol includes aromatic hexaol having 6 to 15 carbon atoms, and examples thereof include hexahydroxybenzene, hexahydroxybiphenyl, and hexahydroxydiphenyldimethylmethane.

  These reaction residues excluding m hydroxyl groups do not necessarily mean reaction residues from which all hydroxyl groups of the polyhydric alcohol have been removed, but some hydroxyl groups remain in the reaction residues. Is also included. Therefore, the number of polyhydric alcohol hydroxyl groups and the value of m do not necessarily match. That is, the relationship between the number of hydroxyl groups (s) in the polyhydric alcohol and the number of hydroxyl groups removed (m) is s ≧ m.

  Among R1, from the viewpoint of peelability of the adhesive, a reaction residue obtained by removing m hydroxyl groups from an alkyl group having 2 to 22 carbon atoms, an alkenyl group having 2 to 22 carbon atoms and a polyhydric alcohol is more preferable. Is an alkyl group having 3 to 18 carbon atoms.

  A hydrogen atom, a C1-C30 alkyl group, or a C2-C30 alkenyl group (R2) is the same as that of R1. Among R2, from the viewpoint of peelability of the adhesive, a hydrogen atom, an alkyl group having 2 to 22 carbon atoms, and an alkenyl group having 2 to 22 carbon atoms are preferable, and a hydrogen atom is more preferable.

  Examples of the oxyalkylene group having 2 to 4 carbon atoms (OA) include oxyethylene, oxypropylene, and oxybutylene. Of these, oxyethylene and oxypropylene are preferable from the viewpoint of peelability of the adhesive.

  When (—OA) n is composed of two or more types of oxyalkylene groups, the bond form of the n oxyalkylene groups may be block, random, or a combination thereof. Further, m (—OA) n—O—R2 may be the same or different.

  n is preferably an integer of 2 to 100, more preferably an integer of 6 to 50. Within this range, the peelability of the adhesive is further improved.

  m is preferably an integer of 1 to 6, more preferably an integer of 1 to 3. Within this range, the peelability of the adhesive is further improved.

Among the compounds represented by the general formula (1), preferred are propanol ethylene oxide 6 mol adduct, propanol ethylene oxide 30 mol / propylene oxide 10 mol random adduct, propanol ethylene oxide 2 mol / propylene oxide 5 mol. / Ethylene oxide 13 mol block adduct, 2-ethylhexanol ethylene oxide 6 mol adduct, 2-ethylhexanol ethylene oxide 30 mol adduct, 2-ethylhexanol ethylene oxide 9 mol / propylene oxide 2 mol block adduct, 2-ethyl Ethanol oxide 30 mol / hexylene propylene oxide 20 mol block adduct, 2-ethylhexanol ethylene oxide 3 mol / propylene oxide 3 mol / ethyleneoxy 10 mol block adduct, 7 mol adduct of ethylene oxide of 8-methyl-1-nonanol, 15 mol adduct of ethylene oxide of 8-methyl-1-nonanol, 1 mol of propylene oxide of 8-methyl-1-nonanol / ethylene oxide 14 mol block adduct, 20 mol propylene oxide of 8-methyl-1-nonanol / 30 mol block adduct of ethylene oxide, 2 mol of ethylene oxide / 2 mol of propylene oxide / 15 mol block adduct of ethylene oxide, 1-dodecanol ethylene oxide 10 mol adduct, 1-dodecanol ethylene oxide 20 mol adduct, 1-dodecanol ethylene oxide 14 mol / propylene oxide 2 mol block adduct, 1-dodecanol ethylene oxide 45 mol, 1 mol of propylene oxide of 1-dodecanol / 20 mol of ethylene oxide block adduct, 2 mol of 1-dodecanol, 2 mol of ethylene oxide / 2 mol of propylene oxide / 13 mol block adduct of octadecan-1-ol, 5 mol of propylene oxide of octadecan-1-ol / Ethylene oxide 20 mol block adduct, octadecan-1-ol ethylene oxide 50 mol adduct, octadecan-1-ol ethylene oxide 5 mol / propylene oxide 3 mol /
Examples include ethylene oxide 20 mol block adducts.

  Examples of the polyoxyalkylene compound other than the compound represented by the general formula (1) include a polyoxyalkylene adduct of castor oil and an oxyalkylene adduct of sucrose.

  Examples of the polyhydric alcohol fatty acid ester include sorbitan octadecenoic acid monoester, glycerin 2-ethylhexanoic acid monoester, diglycerin octadecenoic acid diester, and the like.

  Examples of the anionic surfactant include α-olefin sulfonate, alkylbenzene sulfonic acid and its salt, naphthalene sulfonate-formaldehyde condensate, N-acyl alkyl taurate, alkyl sulfate, alkyl ether sulfate, alkyl sulfosuccinate. Examples thereof include acid salts, alkyl phosphates, and polyoxyethylene alkyl ether phosphates.

  Examples of amphoteric surfactants include higher alkylaminopropionates and higher alkyldimethyl betanic acids.

  Of these, nonionic surfactants and anionic surfactants are preferred, nonionic surfactants are more preferred, polyoxyalkylene compounds are particularly preferred, and compounds represented by the general formula (1) are most preferred.

  The surfactant may contain only one type or a plurality of types.

  In the case where the adhesive peeling accelerator of the present invention contains a surfactant, the content (parts by weight) of the surfactant is preferably 1 to 99, more preferably 5 with respect to 100 parts by weight of the phosphonic acid (salt). ~ 90. Within this range, the peelability of the adhesive is further improved.

  The pressure-sensitive adhesive peeling accelerator of the present invention may contain a solvent and other additives.

  Examples of the solvent include water or a mixed solvent of water and a hydrophilic organic solvent. Examples of hydrophilic organic solvents include esters having 4 to 8 carbon atoms {ethyl acetate, butyl acetate, methoxybutyl acetate, methyl cellosolve acetate and ethyl cellosolve acetate}, ethers having 4 to 8 carbon atoms {ethyl cellosolve, butyl cellosolve and propylene glycol. Monomethyl ether and the like}, ketones having 3 to 8 carbon atoms {acetone, methyl ethyl ketone and methyl isobutyl ketone, etc.}, alcohols having 1 to 8 carbon atoms {methanol, ethanol, n- or i-propanol, n-, i- or t- Butanol, propylene glycol, dipropylene glycol and the like}, and C5-C8 heterocyclic compounds {N-methylpyrrolidone and the like}.

  When the solvent is included, the content (parts by weight) of the solvent is not particularly limited and can be determined as appropriate from the viewpoint of handling properties of the pressure-sensitive adhesive release accelerator, but with respect to 100 parts by weight of the phosphonic acid (salt). Thus, it is preferably about 35 to 10000, more preferably about 45 to 2000.

  Other additives include known additives {defoamers, dispersants, thickeners, fluidity improvers, antioxidants, UV absorbers, deodorants, fragrances, dyes, pH adjusters (citric acid Trisodium and potassium pyrophosphate, etc.) and / or preservatives, etc.}.

  When other additives are included, the content (parts by weight) of the additives is preferably 0.1 to 200, more preferably 1 to 150, with respect to 100 parts by weight of the phosphonic acid (salt). Within this range, the effect of each additive can be exhibited without impairing the peelability of the solvent-borne machine adhesive.

  When the pressure-sensitive adhesive debonding accelerator of the present invention is composed of a plurality of components, the pressure-sensitive adhesive delamination promoter is obtained by uniformly mixing a plurality of components.

  The pressure-sensitive adhesive peeling accelerator of the present invention can be applied in a process in which the pressure-sensitive adhesive adheres to a manufacturing apparatus such as a transfer pump, a pipe, and a screen, and can promote the peeling of the pressure-sensitive adhesive by applying the pressure-sensitive adhesive peeling accelerator. In particular, it is suitable for preventing adhesion of a lignocellulosic material-derived adhesive (adhesive containing lignin, metal ions (calcium ions, iron ions, etc.), metal compounds (calcium carbonate, silicon dioxide, etc.)). There are no limitations on the lignocellulosic material, and examples include wood {coniferous and broadleaf etc.}, non-wood {plants (kenaf, bagasse, bamboo etc.)} and the like.

The manufacturing method of the dissolving pulp of this invention can combine a well-known process without a restriction | limiting especially if the pre-hydrolysis process process of hydrolyzing a lignocellulosic substance in presence of said adhesive substance peeling accelerator is included.
In addition, since the prehydrolysis treatment step is performed in a high-temperature, high-pressure pressure vessel, it is preferable to add the pressure-sensitive adhesive peeling accelerator diluted in water (press-fit into the pressure vessel). It can be determined appropriately in consideration of easiness etc.).
In the pre-hydrolysis treatment step, when the lignocellulosic material is hydrolyzed with water, a naturally-occurring organic acid is gradually generated and the water is changed to acid-treated water. An organic acid (such as acetic acid) or an inorganic acid (such as sulfuric acid) may be used as the hydrolysis catalyst. A known range can be applied to the temperature and time of the hydrolysis reaction.

  The pressure-sensitive adhesive peeled off by the pressure-sensitive adhesive peeling accelerator in the pre-hydrolysis treatment step is dissolved in an alkaline cooking liquid in the next cooking step, and is washed and removed in the subsequent washing step.

  The amount (parts by weight) of the pressure-sensitive adhesive peeling accelerator is not particularly limited and can be appropriately determined depending on the amount of pressure-sensitive adhesive generated, etc., but the treatment liquid (in the case of the prehydrolysis step, water or acidic treated water) 100 0.01-5 are preferable with respect to a weight part, More preferably, it is 0.05-2, Most preferably, it is 0.1-1. Within this range, peeling of the adhesive can be further promoted, and the productivity (ie, production efficiency) of dissolving pulp can be greatly improved.

Parts and% mean parts by weight and% by weight unless otherwise specified.
<Example 1>
167 parts of a 60% aqueous solution of 1-hydroxyethylidene-1,1-diphosphonic acid (Tokyo Kasei Kogyo Co., Ltd.) and 334 parts of water are uniformly mixed to obtain the pressure-sensitive adhesive peeling accelerator (1) (water) of the present invention. The concentration was 80%, and the same applies hereinafter).

<Example 2>
100 parts of 1-hydroxyethylidene-1,1-diphosphonic acid disodium salt (Wako Pure Chemical Industries, Ltd.) and 400 parts of water were uniformly mixed to obtain the pressure-sensitive adhesive peeling accelerator (2) of the present invention. .

<Example 3>
100 parts of methylene diphosphonic acid (Tokyo Chemical Industry Co., Ltd.) and 400 parts of water were uniformly mixed to obtain a pressure-sensitive adhesive peeling accelerator (3) of the present invention.

<Example 4>
200 parts of 50% aqueous solution of 2-phosphonobutane-1,2,4-tricarboxylic acid (Tokyo Kasei Kogyo Co., Ltd.) and 300 parts of water are uniformly mixed to obtain the pressure-sensitive adhesive peeling accelerator (4) of the present invention. It was.

<Example 5>
167 parts of 60% aqueous solution of 1-hydroxyethylidene-1,1-diphosphonic acid (Wako Pure Chemical Industries, Ltd.), 90 parts of an ethylene oxide 6-mol adduct of 2-ethylhexanol prepared by a known alkylene oxide addition reaction, and water 694 The parts were uniformly mixed to obtain the pressure-sensitive adhesive peeling accelerator (5) of the present invention.

<Example 6>
167 parts of 60% aqueous solution of 1-hydroxyethylidene-1,1-diphosphonic acid (Wako Pure Chemical Industries, Ltd.), 2 moles of 1-dodecanol ethylene oxide / propylene oxide 2 moles / ethylene oxide 13 prepared by known alkylene oxide addition reaction 45 parts of the mole block adduct and 514 parts of water were uniformly mixed to obtain a pressure-sensitive adhesive peeling accelerator (6) of the present invention.

<Example 7>
167 parts of a 60% aqueous solution of 1-hydroxyethylidene-1,1-diphosphonic acid (Wako Pure Chemical Industries, Ltd.), 5 parts of an ethylene oxide 50 mol adduct of 1-octadecanol prepared by a known alkylene oxide addition reaction, and 354 parts of water was uniformly mixed to obtain a pressure-sensitive adhesive peeling accelerator (7) of the present invention.

<Creation of adhesive adhesion test piece>
Add a stainless steel piece (SUS304, 1cm x 6cm, thickness 1mm), domestic hardwood chip 100g and water 400g to a 1 liter autoclave, heat-treat at 150 ° C for 6 hours without stirring, and acidity of about pH 3.5 Adhesive adherence that adheres to a stainless steel piece from treated water (naturally-derived organic acid is generated by hydrolysis of lignocellulosic material and the water is changed to acidic treated water. The same applies hereinafter) The test piece was taken out.

<Evaluation of peelability of adhesives-1>
Using a 1 liter autoclave, 15 g of the evaluation sample (adhesive peeling accelerator) and 585 g of water were uniformly mixed (water concentration 99.5%), and one piece of adhesive adhering test piece was added to the autoclave. The test piece was taken out after heat-processing for time. The test piece is immersed in 200 mL of water at 80 ° C. and immediately taken out five times, and the ratio of the area of the adhesive attached to the test piece with respect to the surface area (about 13.4 cm ² ) of the test piece is visually judged. The peelability of the pressure-sensitive adhesive was evaluated according to the following criteria and shown in Table 1.
A blank test piece was prepared in the same manner as described above except that 15 g of the evaluation sample (adhesive peeling accelerator) was changed to 15 g of water, evaluated in the same manner, and shown in Table 1.

Percentage of adhered adhesives ◎: Less than 30% ○: 30 to 70% ×: Ratio exceeding 70%

<Evaluation of adhesive peelability-2>
Add 10 g of evaluation sample (adhesive peeling accelerator), stainless steel piece (SUS304, 1 cm × 6 cm, thickness 1 mm), domestic hardwood chip 100 g and water 390 g to 1 liter autoclave and heat at 150 ° C. for 6 hours without stirring. After the treatment, a piece of stainless steel was taken out from the acid treated water having a pH of about 3.5. The stainless steel piece is immersed in 200 mL of water at 80 ° C. and immediately removed five times, and the ratio of the area of the sticking material adhering to the test piece to the surface area (about 13.4 cm ² ) of the stainless steel piece is visually judged. The peelability of the adhesive adhered to the stainless steel piece was evaluated according to the following criteria and shown in Table 2.
A blank test piece was prepared in the same manner as described above except that 10 g of the evaluation sample (adhesive peeling accelerator) was changed to 10 g of water, and evaluated in the same manner as shown in Table 2.

Percentage of adhered adhesives ◎: Less than 30% ○: 30 to 70% ×: Ratio exceeding 70%

  As shown in Tables 1 and 2, the pressure-sensitive adhesive peel accelerator of the present invention was excellent in the peelability of the pressure-sensitive adhesive.

Claims (6)

A pressure-sensitive adhesive release promoter characterized by containing a phosphonic acid (salt). The pressure-sensitive adhesive peeling accelerator according to claim 1, further comprising a surfactant. The pressure-sensitive adhesive peeling accelerator according to claim 2, wherein the content of the surfactant is from 1 to 99 parts by weight per 100 parts by weight of the phosphonic acid (salt). The pressure-sensitive adhesive peeling accelerator according to claim 2 or 3, wherein the surfactant is a polyoxyalkylene compound. The pressure-sensitive adhesive peeling accelerator according to claim 4, wherein the polyoxyalkylene compound is a compound represented by the general formula (1).

R1 [(-OA) n-OR2] m (1)

R1 is a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms, or a reaction residue obtained by removing m hydroxyl groups from a polyhydric alcohol, R2 is a hydrogen atom, an alkyl having 1 to 30 carbon atoms A group or an alkenyl group having 2 to 30 carbon atoms, OA represents an oxyalkylene group having 2 to 4 carbon atoms, n represents an integer of 2 to 100, and m represents an integer of 1 to 6. A method for producing a dissolving pulp comprising a prehydrolysis step of hydrolyzing a lignocellulosic substance in the presence of the pressure-sensitive adhesive peeling accelerator according to any one of claims 1 to 5.