JP2000355896A - Paper-treating agent and treatment of paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a paper-treating agent free from the generation of formaldehyde and effective for improving the dimensional stability of paper, especially the dimensional stability in wet state by formulating a specific hydroxyl compound with glyoxal. SOLUTION: The objective paper-treating agent is produced by formulating a compound containing at least 2 hydroxyl groups and expressed by formula I (R is H or methyl; and (n) is 1-20), formula II ((n) is 1-20), formula III [(m) is 0-3; and R1 to R11 are each H, OH or a 1-3C (hydroxy) alkyl] and formula IV (R12 is hydroxyl or hydroxymethyl; and R13 is H, hydroxyl, hydroxycarbonyl or the like), e.g. diethylene glycol, tripropylene glycol and cyclohexane dimethanol with glyoxal at a weight ratio of 0.1:10 to 10:0.1. The paper-treating agent is applied to a paper by internal sizing and/or impregnation treatment and a drying and/or heating treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a paper treating agent containing a specific compound and a paper treating method using the same. More specifically, the present invention relates to a paper treating agent containing at least one compound containing at least two hydroxyl groups and glyoxal, and a paper treating method using the same. INDUSTRIAL APPLICABILITY The paper processing agent of the present invention and a paper processing method using the same are useful as a processing agent and a processing method for improving dimensional stability of paper.

[0002]

2. Description of the Related Art A paper treating agent is an internal additive added to the stock in the first half of the pulping process and the paper making process, impregnating the paper web formed in the second half of the paper making process, There is an impregnating agent that is impregnated by a method such as size press, coating, or spray application. Conventional internal additives include bleaching agents such as caustic soda and sodium sulfite, sizing agents such as rosin and starch, dry paper strength agents such as polyvinyl alcohol resin and polyacrylamide, and melamine / formalin resin and urea / formalin resin. Wet strength agents and the like have been used. As the impregnating agent, surface strength improvers such as polyvinyl alcohol and starch, sizing agents such as gelatin, and paper strength enhancers such as resin latex have been used. In particular, formalin-based resins have been used in a wide range of applications such as sizing agents, paper strength agents, water-resistant treatment agents, and flame retardants.

However, since formalin-based resins use toxic formalin as a raw material, they have problems in working environment and safety. Furthermore, formaldehyde may be generated due to the unreacted excess contained in the impregnated paper or the decomposition of the resin, and the health damage has been regarded as a serious problem. Against this background, there has been an increasing movement to substitute formalin-based resins with other resins, and non-formalin-based resins suitable for various applications have been developed.

[0004] In addition, the formalin-based resin achieves the above-mentioned purpose of use and has a slight effect on the dimensional stability of paper. Was getting. However, for the above-mentioned reasons, it has become an issue to reduce the use of formalin-based resins, and there has been a strong demand for non-formalin-based dimensional stabilizers which are excellent in the dimensional stabilization effect of paper when used in small amounts.

It is known to use glyoxal, a chemical containing glyoxal, or a chemical produced from glyoxal as a raw material for the purpose of modifying general paper, as a paper chemical in place of formalin-based resin. For example, Japanese Patent Publication No. 53560/1990 describes that glyoxal is reacted and adhered to a specific paper base material surface by heat treatment to impart liquid permeation suppression properties. JP-A-8-13383 discloses a method for coating paper by applying to a paper an aqueous solution of a water-soluble polymer comprising a composition of a water-soluble polymer and a dialdehyde such as glyoxal.
Japanese Unexamined Patent Publication No. 8-219592 discloses a method for producing a water-soluble acetal-based resin as a fiber processing resin by a co-condensation reaction of a polyhydric alcohol and glyoxal.
Japanese Patent Application Laid-Open Publication No. H11-157, respectively describes using a reaction product of a hydroxy compound and glyoxal as a lubricating insolubilizing agent for a binder for a paper coating composition.

On the other hand, Japanese Patent Application Laid-Open No. 58-239 discloses the use of glyoxal for the purpose of obtaining a dimensional stabilizing effect.
No. 94 and Japanese Patent Publication No. 41760/1994 disclose examples of using an acrylic copolymer and glyoxal in combination. Also, Japanese Patent Application Laid-Open No. 2-33394 discloses that a paper size is measured using a 4,5-dihydroxy-2-imidazolidinone-based compound which is generally known to be obtained by a reaction between glyoxal and a urea compound. It is described that stabilization is to be achieved.

However, according to the above-mentioned method, various physical properties such as insufficient dimensional stabilizing effect, remarkable coloring at the time of heat treatment, extreme reduction in size, and the like are caused. Glyoxal alone has the problem that the stiffness of the paper increases and the texture is impaired.
In addition, in the method using a polymer compound in combination, there is a problem that handling becomes difficult or sticking to a drum or a stain occurs in a paper manufacturing process because the viscosity of the chemical solution becomes high.

[0008] In view of the above background, the present invention provides a paper treating agent which is free from formaldehyde, has a low viscosity, is easy to handle, and has an excellent dimensional stabilizing effect when used in a small amount. It is an object to provide a paper processing method.

[0009]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have found that a paper containing at least one compound containing at least two hydroxyl groups and glyoxal. It has been found that the treating agent for use is very excellent in improving dimensional stability, has good other physical properties and is easy to handle, and has completed the present invention.

That is, the present invention relates to a paper treating agent characterized by comprising (1) at least one compound containing at least two hydroxyl groups and glyoxal, and (2) at least 2 The paper treating agent according to the above (1), wherein the weight ratio of the compound containing two hydroxyl groups to glyoxal is in the range of 0.1: 10 to 10: 0.1, and (3) at least two A compound having a hydroxyl group of the formula (1)

Embedded image (Wherein, R represents a hydrogen atom or a methyl group, and n represents an integer of 1 or more and 20 or less),
Formula (2) [Formula 6]

Embedded image (Where n represents an integer of 1 to 20), a diol compound represented by the formula (3):

Embedded image (In the formula, m represents an integer of 0 to 3, and R ^{1 to} R ¹¹ each independently represent a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 3 carbon atoms, or a hydroxyalkyl group having 1 to 3 carbon atoms. Wherein at least one of R ^{1 to} R ¹¹ is a hydroxyl group or a hydroxyalkyl group having 1 to 3 carbon atoms, and two hydroxyl groups are bonded to the same carbon atom constituting the cyclohexane ring. Except in the case))
A diol compound having a cyclohexane ring represented by
And formula (4)

Embedded image (Wherein, R ¹² represents a hydroxyl group or a hydroxymethyl group, and R ¹³ may be optionally substituted with a hydrogen atom, a hydroxyl group, a hydroxycarbonyl group, or a hydroxyl group, a hydroxycarbonyl group, a halogen atom, or an alkoxy group. The above (1) or (2), which is at least one compound selected from the group consisting of a dihydroxy-substituted carboxylic acid compound and / or a salt thereof, which is represented by a good hydrocarbon group having 1 to 8 carbon atoms. Paper processing agent,
(4) The compound containing at least two hydroxyl groups is ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetramethylene glycol, cyclohexanediol, cyclohexanedimethanol, 2,2- Bis (hydroxymethyl) propionic acid and / or a salt thereof, and 2,2-bis (hydroxymethyl) butanoic acid and / or a salt thereof,
The paper treating agent according to the above (1) or (2), which is at least one compound selected from the group consisting of: and a paper treating method using these.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The paper treating agent of the present invention contains one or more compounds having at least two hydroxyl groups (hereinafter abbreviated as hydroxyl compounds) and glyoxal.

Although the hydroxyl compound is not particularly limited, it is preferable that the solubility in water is 1% by weight or more because it is necessary to apply and impregnate the paper as an aqueous solution. From the viewpoint of providing a certain low-viscosity treating agent, the molecular weight of the compound is preferably about 1,000 or less. Among such compounds, the compound represented by the formula (1)

Embedded image (Wherein, R represents a hydrogen atom or a methyl group, and n represents an integer of 1 or more and 20 or less),
Formula (2)

Embedded image (Where n represents an integer of 1 to 20), a diol compound represented by the formula (3):

Embedded image (In the formula, m represents an integer of 0 to 3, and R ^{1 to} R ¹¹ each independently represent a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 3 carbon atoms, or a hydroxyalkyl group having 1 to 3 carbon atoms. Wherein at least one of R ^{1 to} R ¹¹ is a hydroxyl group or a hydroxyalkyl group having 1 to 3 carbon atoms, and two hydroxyl groups are bonded to the same carbon atom constituting the cyclohexane ring. Except in the case))
A diol compound having a cyclohexane ring represented by
And formula (4)

Embedded image (Wherein, R ¹² represents a hydroxyl group or a hydroxymethyl group, and R ¹³ may be optionally substituted with a hydrogen atom, a hydroxyl group, a hydroxycarbonyl group, or a hydroxyl group, a hydroxycarbonyl group, a halogen atom, or an alkoxy group. One or more compounds selected from the group consisting of dihydroxy-substituted carboxylic acid compounds and / or salts thereof represented by a good hydrocarbon group having 1 to 8 carbon atoms) are preferably used.

Specific examples of such compounds include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, tetramethylene glycol, cyclohexanediol, ( (Hydroxymethyl) cyclohexanol, (hydroxyethyl) cyclohexanol, (hydroxypropyl) cyclohexanol, cyclohexanedimethanol, cyclohexanetriol, cyclohexanetetraol, cyclohexanepentaol, cyclohexanehexol, cyclohexanetrimethanol, cyclohexanetetramethanol, cyclohexanepentamethanol , Cyclohexane hexameta , Methylcyclohexanediol, methylcyclohexanedimethanol, 2,3-dihydroxypropionic acid, 2,2,3-trihydroxypropionic acid, 2-hydroxy-2-hydroxymethylmalonic acid, 2-hydroxy-2-hydroxy Methylpropionic acid, 2,3-dihydroxy-2-hydroxymethylpropionic acid, α-hydroxy-α-hydroxymethylphenylacetic acid, 3-hydroxy-2-hydroxymethylpropionic acid, 2,3-dihydroxy-2-hydroxymethylpropion Acid, 2,2-bis (hydroxymethyl) malonic acid, 2,2-bis (hydroxymethyl) propionic acid, 3-hydroxy-2,2-bis (hydroxymethyl) propionic acid, 2,2-bis (hydroxymethyl ) Butanoic acid, 3-chloro-2,2- Scan (hydroxymethyl) propionic acid, alpha, alpha-bis can be mentioned (hydroxymethyl) phenylacetic acid, and / or their salts. Particularly preferred as the hydroxyl compound are ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetramethylene glycol, cyclohexanediol, cyclohexanedimethanol, 2,2-bis (hydroxymethyl) propionic acid and / Or a salt thereof, and 2,2-bis (hydroxymethyl) butanoic acid and / or a salt thereof,
One or more compounds selected from the group consisting of

When the carboxylic acid compound represented by the formula (4) is used as the above-mentioned hydroxyl compound, it may be used in the form of a carboxylic acid as it is or a salt with a basic substance without any problem. Can be used. Examples of such a salt of the compound of the formula (4) include ammonium salts with ammonia or 1-3-substituted amines, alkali metal salts such as lithium, sodium and potassium, alkaline earth metal salts such as magnesium and calcium, and transition metal salts. Examples thereof include, but are not limited to, salts.

In the present invention, one of the hydroxyl compounds
Glyoxal used together with more than one species is a readily available compound, regardless of its synthesis method, concentration and form. Glyoxal is generally commercially available as an aqueous solution of about 40% by weight, but may be used after diluting or concentrating it.

The paper treating agent of the present invention comprises mixing at least one of the above-mentioned hydroxyl compounds and glyoxal with water;
Prepared by dissolution. Glyoxal, when applied to a paper substrate, provides a large dimensional stabilizing effect on the wetting / drying of the paper, and the hydroxyl compound used at the same time contributes to the dimensional stabilizing effect, while at the same time increasing stiffness, which is a disadvantage of glyoxal. And has the function of keeping various physical properties such as texture and size properties in a good range.
Therefore, by appropriately adjusting the type of hydroxyl compound used, its mixing ratio, and the amount used for paper,
It is possible to adjust various physical properties of the paper at the same time while obtaining the dimensional stabilizing effect.

The mixing ratio of the hydroxyl compound and glyoxal is not particularly limited since it is appropriately selected depending on the properties of the paper base material to which the paper treating agent is to be applied and the required physical properties of the paper after application. 0.1: 10 to 10: in ratio
A range of 0.1 is preferred. When the weight ratio of the hydroxyl compound to glyoxal is 0.1: 10 or less,
It is difficult to obtain the effect of suppressing stiffness and improving the texture of the hydroxyl compound, and if the weight ratio of the hydroxyl compound to glyoxal is 10: 0.1 or more, it is difficult to obtain the dimensional stabilizing effect of glyoxal, which is not preferable. .

The total weight concentration of the hydroxyl compound and the glyoxal in the paper treating agent of the present invention is not particularly limited, but is usually adjusted in the range of 0.1% by weight to 70% by weight. The paper treating agent thus prepared may be used as it is, or may be used after diluting. If necessary, the pH may be adjusted with an appropriate acid or base.

Various catalysts can be added to the paper treating agent of the present invention. As the catalyst, for example, magnesium chloride, magnesium borofluoride, zinc chloride, zinc borofluoride, zinc nitrate, iron chloride, iron sulfate, cobalt chloride,
Examples thereof include metal salts such as cobalt sulfate, acids such as hydrochloric acid, sulfuric acid, acetic acid, glycolic acid, and lactic acid, ammonium chloride, and hydrochlorides of organic amines. These catalysts can be used alone or in combination of two or more. The amount of the catalyst to be used is generally in the range of 0.01 to 50% by weight, preferably 0.1 to 20% by weight, based on glyoxal contained in the paper treating agent.

The paper treating agent of the present invention comprises a paper-strengthening agent, a leveling agent, an antifoaming agent, a penetrant, a coloring agent, a pigment, a thickening / thickening agent, a surfactant and the like. It is also possible to mix and use various additives generally used in the above.

The method for treating paper according to the present invention is carried out by applying the aqueous paper treating agent prepared as described above to paper or paper stock and evaporating moisture to fix the paper fibers.

The paper referred to in the present invention is a paper using a paper material containing cellulose-based pulp fiber and / or waste paper pulp as a main component, such as wood, straw, bamboo, reed, and sugarcane meal. Includes those containing synthetic resins. Specific examples include cardboard base paper, various printing papers, processed base paper, packaging paper, and the like.

The method for treating paper using the paper treating agent of the present invention includes at least an internal addition and / or impregnation step and a drying and / or heat treatment step.

The internal addition step is a step of adding a paper treating agent to the stock before forming the web. The impregnating step is a method of impregnating the paper web formed in the paper making step with a paper treating agent, but may be a step of reworking the once made and dried base paper. Among these methods, a method of impregnating a paper web is particularly preferably used.

As the impregnation method, a general method such as size press, impregnation processing, coating, spray coating, etc. can be appropriately selected and carried out, but a method of impregnation by size press and impregnation processing is preferable. The impregnation time for the size press and the impregnation process varies depending on the type of paper, but is usually in the range of 1 second to 10 minutes, preferably in the range of 10 seconds to 5 minutes.

The drying and / or heat treatment step is a step of drying and / or heat treating the paper containing the paper treating agent by the internal addition and / or impregnation step. At this time, if necessary, preliminary drying may be used in combination. The drying and / or heat treatment method of the paper may be a batch processing method such as a suspension type or a continuous processing method such as a paper making process. As a device to be used, a commonly used dryer, paper machine dryer, Yankee dryer and the like can be appropriately used.

The drying and / or heat treatment temperature may be generally a temperature at which water evaporates, but is preferably in a range of 50 ° C. or more to a temperature not adversely affecting the paper, ie, 5 ° C.
0 ° C to 150 ° C is good. The drying and / or heat treatment time is not particularly limited because it is appropriately selected depending on the type and capacity of the apparatus, the temperature, and the like, but is generally in the range of 10 seconds to 15 minutes.

The amount of impregnation of the treating agent by the treating method according to the present invention as a solid content is usually 0.1 to 20% by weight, preferably 1 to 10% by weight, based on the weight of the paper to be treated. Range. When the impregnation amount is less than 0.1% by weight,
A sufficient dimensional stabilizing effect cannot be obtained. In addition, 20% by weight
If it exceeds, the dimensional stabilizing effect can be sufficiently obtained, but the effect corresponding to the amount used cannot be obtained, which is uneconomical, and the physical properties of the treated paper may be deteriorated, which is not preferable.

The paper treating agent of the present invention has an effect on dimensional stability when applied to paper, and particularly has an excellent effect on dimensional stability in water. Further, it has a low viscosity and is easy to handle as compared with a conventional paper processing agent using glyoxal in combination. Furthermore, by the method for treating paper using the treating agent, it is possible to obtain a treated paper having improved dimensional stability and various physical properties such as texture and size of the paper. Therefore, the present invention can be used as a processing agent and a processing method for wallpaper, filters, household paper, and the like, and can be particularly suitably used as a base paper for wallpaper.

[0030]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto unless it exceeds the gist of the present invention.

Example 1 (Preparation 1 of paper treating agent) 35 g of 1,4-cyclohexanediol (mixture of cis form and trans form), 40% aqueous glyoxal solution
5 g and 427.5 g of distilled water were mixed to prepare a paper treating agent.

Example 2 (Preparation 2 of paper treating agent) 100 g of oxidized starch was mixed with 800 ml of distilled water, and heated in a hot water bath at 90 to 95 ° C for 30 minutes with stirring. Distilled water was added to the obtained viscous liquid to make the total amount 1 kg, and mixed well to prepare a 10% by weight oxidized starch solution. A paper treating agent was prepared by mixing 100 g of this oxidized starch solution, 30 g of 1,4-cyclohexanediol (a mixture of cis- and trans-forms), 25 g of a 40% aqueous glyoxal solution, and 345 g of distilled water.

Example 3 (Paper treatment 1) The paper treating agent prepared in Example 1 was placed in a flat container (length 0.30
0 m × 0.350 m × 0.050 m depth), and the raw paper with a basis weight of 80 g / m ² was cut into the fourth row of row A (0.297 m × 0.210 m). For 2 minutes to impregnate the treating agent. Next, the sheet is taken out, and corresponds to one type defined in a square filter paper (JIS P3801 [filter paper (for chemical analysis)].
(0.350 m in width) Excess treatment agent adhering to the surface between the two sheets was absorbed. This impregnated paper is subjected to a temperature of 20 ° C. and a humidity of 6
After naturally drying in a 5% constant temperature and humidity room for 12 hours, a drum type paper dryer (manufactured by JAPOH Co., Ltd., automatic polishing dryer L)
Drying and heat treatment were performed under the conditions of 110 ° C. and 60 seconds using (−3 type). Thereafter, the temperature 20 ° C., after dampening overnight conditioned at 65% constant temperature and humidity chamber humidity was measured by weight of the paper, impregnated amount of the treating agent nonvolatile content was 1.85 g / m ^2. In addition, a blank test was performed by the same operation using distilled water instead of the paper treating agent. 1 liter of distilled water adjusted to 20 ° C. was placed in a flat container, where the length was 0.250 m and the width was 0.0
The test paper cut to 50 m was soaked for 10 minutes to measure the dimensional stability when wet (water elongation = elongation when wet / length when dry × 100 (%)). As a result, the underwater elongation of the blank test paper was 1.64%, whereas the underwater elongation of the test paper treated with the paper treating agent of Example 1 was 1.10.
%, And an effect of suppressing elongation in water of 32.9% was obtained.
Further, when the sizing degree was measured according to the “Steechig sizing degree test method for paper” specified in JIS (Japanese Industrial Standards) P8122, the sizing degree of the blank test paper was 35 seconds, and the blank for the paper of Example 1 was used. The sizing degree of the test paper treated with the treating agent was 25 seconds. In addition, the texture of the paper treated with the paper treating agent of Example 1 was equivalent to that of blank test paper, and was confirmed to be good.

Example 4 (Paper Treatment 2) Using the paper treating agent prepared in Example 2, unprocessed base paper was treated under the same conditions as in Example 3. The impregnation amount of the treating agent non-volatile component was 1.88 g / m ² . The blank test was performed using an oxidized starch solution prepared by mixing 100 g of the 10% by weight oxidized starch solution prepared in Example 2 with 400 g of distilled water. When the dimensional stability was measured in the same manner as in Example 3, the underwater elongation of the blank test paper was 1.63%, whereas the underwater elongation of the test paper treated with the paper treating agent of Example 2 was measured. Was 1.24%, and an effect of suppressing elongation in water of 23.8% was obtained. The sizing degree of the blank test paper was 32 seconds, whereas the paper treated with the paper treating agent of Example 2 was 2 seconds.
6 seconds. The texture of the paper treated with the paper treating agent of Example 2 was good.

Examples 5 to 12 The same paper treating agents as in Example 2 were prepared using the treating agent compositions shown in Table 1, and the raw base paper was treated in the same manner as in Example 4. The results are shown in Table 1.

Comparative Examples 1-3 1,4-cyclohexanediol, glyoxal, and N, N'-dimethyl-4,5-dihydroxy-2-imidazolidinone were used alone and mixed with an oxidized starch solution. A processing solution for comparison was prepared, and the raw base paper was processed. Table 1 shows the composition of the treatment liquid and the test results.

As is clear from the comparative examples, when the hydroxyl compound was used alone, a sufficient dimensional stabilizing effect was not obtained, and when glyoxal was used alone, the stiffness of the paper was increased, and the texture was increased. In addition to being defective, an extreme increase in the degree of size was observed, indicating that it was insufficient as a paper processing agent.

On the other hand, when the paper is processed using the paper processing agent and the processing method of the present invention, a high dimensional stabilizing effect can be obtained, and at the same time, the texture of the processed paper is maintained, and the paper is further processed. An appropriate degree of size suitable for use as waste paper can also be ensured.

[0039]

[Table 1]

[0040]

According to the paper treating agent of the present invention and the paper treating method using the same, the dimensional stability of paper, especially when wet, is improved by using a treating agent which does not generate formaldehyde. At the same time, the physical properties of the paper can be maintained in a good state.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Naoki Sato 30 Asamuta-cho, Omuta-shi, Fukuoka Prefecture F-term (reference) 4J002 CH011 EC037 EC047 EE016 EF037 GK04 4L055 AG77 AG93 AH49 AH50 BE10 FA18 FA20

Claims (8)

[Claims] 1. A paper treating agent comprising at least one compound having at least two hydroxyl groups and glyoxal. 2. The weight ratio of the compound containing at least two hydroxyl groups to glyoxal is 0.1: 1.
The paper treating agent according to claim 1, wherein the ratio is in the range of 0 to 10: 0.1. 3. A compound containing at least two hydroxyl groups is represented by the formula (1): ## STR1 ## (Wherein, R represents a hydrogen atom or a methyl group, and n represents an integer of 1 or more and 20 or less),
Formula (2) [Formula 2] (Wherein, n represents an integer of 1 or more and 20 or less), a diol compound represented by the formula (3): (In the formula, m represents an integer of 0 to 3, and R ^{1 to} R ¹¹ each independently represent a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 3 carbon atoms, or a hydroxyalkyl group having 1 to 3 carbon atoms. Wherein at least one of R ^{1 to} R ¹¹ is a hydroxyl group or a hydroxyalkyl group having 1 to 3 carbon atoms, and two hydroxyl groups are bonded to the same carbon atom constituting the cyclohexane ring. Except in the case))
A diol compound having a cyclohexane ring represented by
And formula (4) [Formula 4] (Wherein, R ¹² represents a hydroxyl group or a hydroxymethyl group, and R ¹³ may be optionally substituted with a hydrogen atom, a hydroxyl group, a hydroxycarbonyl group, or a hydroxyl group, a hydroxycarbonyl group, a halogen atom, or an alkoxy group. The paper for paper according to claim 1 or 2, wherein the compound is at least one compound selected from the group consisting of a dihydroxy-substituted carboxylic acid compound represented by the following formula (1) and a salt thereof. Processing agent. 4. The compound containing at least two hydroxyl groups is ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetramethylene glycol, cyclohexanediol, cyclohexanedimethanol, 2. The compound according to claim 1, which is at least one compound selected from the group consisting of 2-bis (hydroxymethyl) propionic acid and / or a salt thereof, and 2,2-bis (hydroxymethyl) butanoic acid and / or a salt thereof. 2. The paper treating agent according to 2. 5. A paper processing method using the paper processing agent according to claim 1. 6. A paper processing method using the paper processing agent according to claim 2. 7. A paper processing method using the paper processing agent according to claim 3. 8. A paper processing method using the paper processing agent according to claim 4.