JP2903256B2 - Latent bulky pulp composition and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a sheet having excellent bulkiness and excellent moldability and processability, maintaining strength, and retaining excellent properties of cellulosic fibers such as liquid absorption and moisture absorption. It provides a preferred material for the production of mat.

[Conventional technology and its problems]

A technique is known in which pulp is subjected to a cross-linking reaction with formalin or the like to make the pulp bulky. However, in order to increase the bulkiness of the pulp in such a way, there is a drawback that the fiber becomes short during defibration after crosslinking. In order to avoid this, there is a technique for facilitating defibration by adhering 1% or more of defibrillation aids to pulp. The possibility of a pulp-based bulky nonwoven fabric is presumed, but the crosslinking reaction Due to the reduction of hydroxyl groups, the reduction of the amount of hydrogen bonds involving water, and the formation of a sheet as it is due to the small number of adhesion points due to the bulkiness, the sheet strength is significantly reduced even if the bulkiness is excellent, There is no moldability and workability, and a practical level sheet cannot be obtained.

However, as in the conventional examples of the present invention, a bulky sheet produced by mixing paper with a heat-fusible fiber chopp and a hot-water-soluble fibrous binder produces bulkiness, moldability, and functionality. And many applications are expected.

However, in this case, when heat-fusible fibers having a low specific gravity are used, mixing with pulp fibers becomes a problem during papermaking, and it is difficult to make the fibers uniform.

On the other hand, when the pulp is crosslinked and defibrated, the pulp becomes 10 times or more bulky as compared with the uncrosslinked pulp under no load depending on the crosslinking conditions. This can be pressed to reduce its thickness, but there is a problem in that storage and transportation require a great deal of cost.

[Problems to be solved by the invention]

The present inventor has conducted intensive studies on the above technical problems relating to the bulky pulp composition. As a result, by using a specific hydrophobic fiber chop instead of the heat-fusible fiber and the hot-water-soluble fibrous binder, a latent bulky composition is obtained, which can eliminate all of the above. The inventors have found that the present invention has been completed based on this finding.

As is apparent from the above description, the object of the present invention is to easily open the pulp of the crosslinked pulp, to store and transport the pulp easily, and to have excellent mixing properties with the heat-fusible fiber and other binder fibers during papermaking. Accordingly, it is an object of the present invention to provide a potentially bulky pulp composition which does not have bulkiness itself but easily becomes bulky by a defibrating operation, and a method for producing the same.

[Means for solving the problem]

The present invention has been made to achieve the above object, and the gist thereof is as follows. That is, the pulp composition of the present invention is (1) a latent bulky pulp composition obtained by reacting a mixture of pulp and a hydrophobic fiber chopping agent with a crosslinking agent; (3) the reaction temperature of the crosslinking agent is lower than the melting point of the hydrophobic fiber used; (4) the hydrophobic fiber Particularly preferred are those containing a composite heat-fusible fiber obtained by composite melt-spinning of two or more kinds of thermoplastic polymers having different melting points.

A mixture of pulp and a mixture of hydrophobic fibers and a crosslinking agent in the presence of a softening agent for fibers is used to form a paper, sheet, or mat in the same specific gravity as a normal mixture of pulp and hydrophobic fibers. It can be stored and transported without any problems, and does not increase the cost.

It is extremely easy to disintegrate this underwater. This is because the hydrophobic fiber prevents the pulp from firmly fixing due to hydrogen bonding, and furthermore, the softening agent of the fiber improves the slip between the pulp fiber and the hydrophobic fiber, and is easy to defibrate and is a flexible bulky composition. Can be obtained. However, it is necessary to maintain the reaction temperature of the crosslinking reaction at a temperature lower than the melting point of the fiber used for mixing. When it is near or above the melting point,
The fusion of the hydrophobic fibers occurs, making defibration difficult, which is opposite to the purpose.

The hydrophobic fiber according to the present invention has poor affinity for water and does not dissolve or swell in contact with water. Such as polyolefins, polyesters,
Examples thereof include polyamide-based, polyimide-based, and polyacryl-based materials that do not have a hydrophilic group in the molecule.

Further, those manufactured by using heat-fusible fibers alone or as a mixture as the hydrophobic fibers can be made into sheets or mats as they are after defibration or by mixing with pulp fibers or other fibers, These can be partly melted by heating to increase the sheet strength while maintaining the bulkiness,
Molding and processing such as heat sealing and embossing are possible. Specific examples thereof include a polyester fiber and a polyamide fiber. In particular, a fibrillated polyolefin-based synthetic pulp developed for papermaking is preferable.
More preferred are composite heat fusible fibers composited with two or more polymers having different melting points.

When a sheet or mat prepared by blending the composite heat-fusible fiber is subjected to a heat sheet, embossing, or other forming process, the heating temperature is lower than the softening point of the high-melting polymer in the fiber but lower than that of the low-melting polymer. By processing at a temperature higher than the softening point, the low-melting-point polymer portion is melted, and the composite heat-fusible fibers are fixed to each other, and embossing and the like are easily performed. In this case, the high-melting polymer fiber does not change its shape and contributes to maintaining the strength of the sheet itself, and the portion that is not heated during embossing is kept bulky by the bulky pulp, so it is bulky and has excellent embossability and is strong and decorative. And a cellulosic bulky sheet excellent in the above can be obtained.

Therefore, the required amount of composite heat-fusible fiber is mixed in advance, or pulp or other fiber is mixed with the mixture obtained by mixing more than the required amount to obtain a desired sheet or mat. Can be.

There are many types of composite heat-sealable fibers in which two or more polymers having different melting points are combined, and there are a large number of polymers to be combined and the production of the fibers. it can.

As a specific example, firstly, there is a polypropylene / polyethylene composite fiber (trade name: Chitsopolypro ES fiber), and the melting point of each of the low-melting components is 135 ° C. or less, and 100 ° C. or less. Things.

In addition, polyester / low melting point polyester, polyester / low melting point polyethylene, polypropylene / low melting point ethylene-vinyl acetate copolymer, nylon 66 / nylon 6, nylon 6 / polyethylene, polyester / nylon 6 and the like can be used.

As the softening agent for the fiber in the present invention, a softening agent, a soft finishing agent and a smoothing agent which are usually used in the textile industry can be used. They facilitate the defibration by lowering the frictional resistance of the fiber surface and making the fiber slippery, and the product has a crosslinked structure, so that it is originally hard but soft and supple. These softeners include a cationic type, an anionic type, amphoteric type, and a nonionic type, and the cationic type has the ability to reduce the friction coefficient of the fiber surface even if it has a good friction coefficient, and thus is suitable for the purpose of the present invention.

For example, Quaternary ammonium salts, amine salts and amides. When the product is intended to absorb water, it is desirable to use an anionic, nonionic or amphoteric softener.

Also, a softening agent commercially available for home use and used at the time of washing is effective.

A sufficient effect can be obtained when the amount of the softener used is 0.1% or less. Usually, it can be used with an adhesion amount of 0.05% or less, so when defibrating and making paper, COD or BOD load on drainage is light, which is preferable.

As a material giving bulkiness to pulp by a crosslinking reaction, those having two or more functional groups that react with cellulose in a molecule, and these are immobilized in a crimped state of the pulp by crosslinking within or between cellulose molecules. It is presumed to be bulky and to have excellent dimensional stability.

The chemical structure of the crosslinker has at least two atoms between the functional groups and reacts with methylol, alkoxymethyl, aldehyde, isocyanate, epoxy, vinyl carboxylic acid, acid anhydride and other hydroxyl groups of cellulose. Have multiple.

Further, a halogen-containing compound such as epichlorohydrin can be effectively crosslinked and used by using an alkali such as caustic soda.

More preferably, it has a cyclic structure between the crosslinkable functional groups. Particularly, a compound having an N-methylol group as a crosslinkable functional group is preferable because it has high reactivity. The same applies to the alkoxylated N-alkoxymethyl compounds for stabilizing and / or controlling the reactivity. The following are specific examples.

Examples include dimethylol ethylene urea, dimethylol dihydroxyethylene urea, dimethylol propylene urea, dimethylol urone, (tetra, tri, di) methylol acetylenediurea, and (tetra, tri, di) methylol melamine.

When these N-methylol compounds are used, a trace amount of formalin is generated by a treatment at a high temperature or a treatment other than making the pH neutral. As a countermeasure for this, there is a method of suppressing with free formalin by using a formalin scavenger or the like.

The problem can be solved by using a non-formalin type crosslinking agent. As such a compound, an epoxy compound such as ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, glycerol glycidyl ether, neopentyl glycol diglycidyl ether, dihydroxyethylene urea, and 1,3-dimethyl derivative are effective.

The amount of these crosslinking agents used is preferably 2% by weight or more based on the pulp, and is preferably within 50%.

The method for producing the potentially bulky pulp composition of the present invention is such that pulp and hydrophobic fiber are mixed and stirred uniformly in an aqueous solution containing a crosslinking agent, a catalyst and a fiber softener so that a predetermined amount of the crosslinking agent adheres. Then, it is dried and then subjected to a heat crosslinking reaction to produce the product. Here, a chop is a long fiber
A short fiber obtained by cutting into a length of 1 cm or less, preferably several mm. The mixing ratio is 95 to 5 parts, preferably 20 to 80 parts, to 80 to 20 parts of hydrophobic fiber to 5 to 95 parts of pulp by weight.

The product can be dried, such as sheet or matte or lump,
Although the specific gravity varies depending on the apparatus for the crosslinking reaction, the specific gravity is the same as that of a normal pulp system, there is no bulkiness, and there is no problem such as an increase in storage and transportation costs.

This can be easily defibrated by performing a normal disintegration operation when producing a bulky sheet, and an extremely bulky pulp can be obtained. Further, in the case of manufacturing by mixing bulky crosslinked pulp and heat fusible fibers in order to maintain processability, heat fusible fibers are mixed as hydrophobic fibers of the present invention and mixed at a temperature below the melting point. By performing a cross-linking reaction, the sheet can be defibrated and used as it is, or mixed with pulp or other fibers to produce a sheet having excellent processability such as heat sealability and embossability.

Usually, when mixing pulp and a heat-fusible fiber chopping paper, it is difficult to mix them uniformly because they are used in a dilute state. For this reason, a mixing method is devised or a special surfactant is used to prevent separation.

In the composition according to the present invention, the pulp and the heat-fusible fiber used can be easily homogenized and hardly separated as compared with the case where the composition is mixed at the time of preparing the sheet. This property becomes even more remarkable when a cross-linking reaction is carried out on a pulp and a heat-fusible fiber, i.e., a hydrophobic fiber, which is uniformly mixed and subjected to a fibrillation operation.

Although the composition of the present invention is preferably used in combination with a papermaking method, it is defibrated in water, dried and then used as a raw material for a bulky sheet or mat by a dry method and has excellent uniform workability. A cellulosic bulky sheet or mat can be obtained.

(Effects)

Preferred as a raw material for the production of a cellulose-based bulky sheet according to the present invention, in terms of storage and transportation, easily becoming bulky when used, and preferably containing a heat-fusible fiber that makes the bulky sheet excellent in workability. Thing is obtained non-woven fabric,
It can be widely used as functional paper.

Example 1 (Manufacturing) Softwood pulp and polypropylene / polyethylene composite heat-fusible fiber (Chisso Corporation, Chitsuso Polypro Fiber ES Chirop, 3 denier, cut length: 5 mm) were taken at a ratio of 8: 2 and used in the following processing solution for home use. Using a small mixer for mixing.

Treatment liquid composition Dimethylol dihydroxyethylene urea 5 parts Zinc nitrate 0.5 parts Dialkyl dimethyl ammonium chloride 0.02 parts (Epocoll SD-75, Miyoshi Oil & Fat Co., Ltd.) 94.5 parts water
1 (liquid / mixture) was dried at 100 ° C. for 1 hour, and then heated and reacted at 115 ° C. for 20 minutes to obtain a latent bulky sheet.
The thickness was almost the same as that of the same treated without a crosslinking agent (uncrosslinked system).

(Evaluation) This was defibrated in water using a household mixer.
When the rotational load of the mixer was adjusted to 40 V with a slider and the fibrillation was performed with weak stirring, the time during which the fibrillation was recognized as 90% or more was less than 20 seconds.

After fibrillation, a sheet-shaped sample was obtained by suction while slightly compressing using a glass funnel, and the sample was dried.

The weight increase of this product was 11.3% based on the pulp used, and the thickness was measured with no load. As a result, the thickness was 10.5 times that obtained by performing the same treatment without a crosslinking agent.

(Sheet formation) The bulky crosslinked pulp composition 97 obtained as described above
Part and polyvinyl alcohol fiber (PVA binder fiber,
A stock was prepared by dispersing 3 parts of VP105-2 (Kuraray Co., Ltd.) in water using polyacrylamide (PAM manufactured by Iron and Steel Chemical Co., Ltd.) as a dispersant. The cross-linked pulp and the ES fiber chops remained uniform without separation during stock preparation. This was sheet-formed with a tappy type standard sheet machine and dried with a Yankee dryer to obtain a bulky sheet. Weighing
It was set to 200g / m ^2. The thickness was measured, and a tensile test was performed in accordance with JIS P 8113 to measure the breaking length. Sheet manufacturing conditions,
The results of the tensile test and other measurements are shown in the table.

Comparative Example 1 A crosslinking reaction was carried out in the same manner as in Example 1 except that no chopping of ES fiber and addition of a softener were performed. The fibrillation of the product was less than 50% in the fibrillated state even when the rotational load of the mixer was 120 V for a slider tack of 40 V for 120 seconds. The load was increased to 80 V, defibration was performed, and overdrying was performed to produce a bulky crosslinked pulp.
The weight increase was 9.8% with respect to the pulp used, and the thickness was measured without load. As a result, the thickness was 10.2 times as large as that obtained by performing the same treatment without a crosslinking agent.

97 parts of bulky crosslinked pulp obtained as described above and PVA
3 parts of binder fibers were dispersed in water using PVM as a dispersant to prepare a stock. This was paper-made using a tappy type standard machine and dried with a Yankee dryer to obtain a bulky sheet. A tensile test and other measurements were performed in the same manner as in Example 1. The sheet production conditions, tensile test and other measurement results are shown in the table.

Comparative Example 2 A stock was prepared by dispersing 77 parts of softwood pulp, 20 parts of ES chop and 3 parts of binder fiber in water using PAM as a dispersant. In this case, during mixing and stirring, the ES chip blows in air bubbles and facilitates floating separation, so the stirring speed is slowed down and the sheet is made uniform with a tappy-type standard machine, and the sheet is dried with a Yankee dryer to obtain a sheet. Example 1
The tensile test and others were measured in the same manner as described above. Sheet manufacturing conditions,
The results of the tensile test and other measurements are shown in the table.

Example 2 Softwood pulp and ES chop were taken at a ratio of 85:15, and a latent bulky pulp composition was produced and evaluated in the same manner as in Example 1 except that the treatment liquid had the following composition. The results are shown in the table.

Treatment solution Dimethylol dihydroxyethylene urea 10 parts Zinc nitrate 1 part Polyamine / polyamide type softener 0.02 parts (Hisoflon MX manufactured by Miyoshi Oil & Fat Co., Ltd.) Water 89 parts Further, a bulky sheet is manufactured in the same manner as in Example 1 and a tensile test is performed. Other measurements were taken. The results are shown in the table.

Example 3 A potentially bulky pulp composition was produced and evaluated in the same manner as in Example 1 except that softwood pulp and ES chip were taken at a ratio of 85:15 and the treatment liquid was made to have the following composition. The results are shown in the table.

Treatment solution Tetramethylol acetylene diurea 5 parts Zinc nitrate 1 part Epocol SD-75 0.02 parts Water 94 parts Further, a bulky sheet was obtained in the same manner as in Example 1, and a tensile test and other measurements were performed. The results are shown in the table.

Example 4 A potentially bulky pulp composition was produced and evaluated in the same manner as in Example 1 except that softwood pulp and ES chip were taken at a ratio of 85:15 and the treatment liquid was made to have the following composition. The results are shown in the table.

Treatment liquid Glycerol diglycidyl ether 10 parts Zn (BF ₄ ) ₂ 2 parts Epocor SD-75 0.02 parts Water 88 parts Further, a bulky sheet was obtained in the same manner as in Example 1, and a tensile test and other measurements were performed. The results are shown in the table.

Example 5 A latent solution was prepared in the same manner as in Example 1 except that the ratio of softwood pulp to polypropylene fiber (P Chisop, manufactured by Chitso Corporation) was 80:20, the treatment solution was as follows, and the reaction temperature was 120 ° C. for 15 minutes. A bulky pulp composition was manufactured and evaluated. The results are shown in the table.

Treatment liquid Dimethylol dihydroxyethylene urea 5 parts Zinc nitrate 1 part Water 94 parts Example 6 The following treatment liquid was used as the treatment liquid with the ratio of softwood pulp to P-chito of 70:30, and a latent bulky pulp composition was prepared in the same manner as in Example 5. Was manufactured and evaluated. The results are shown in the table.

Treatment liquid Dimethylol dihydroxyethylene urea 10 parts Zinc nitrate 1 part Water 89 parts Manufactured and evaluated. The results are shown in the table.

Treatment solution Glycerol diglycidyl ether 10 parts Zn (BF ₄ ) ₂ 2 parts Water 88 parts

Claims (8)

(57) [Claims] A latent bulky pulp composition obtained by reacting a crosslinking agent with 100 parts by weight of a mixture of 5-95 parts by weight of pulp and 95-5 parts by weight of hydrophobic fibers. 2. The potentially bulky pulp composition according to claim 1, wherein the crosslinking agent is reacted in the presence of a fiber softener. 3. The latent bulky pulp composition according to claim 1, wherein the temperature at which the crosslinking agent is reacted is not higher than the melting point of the hydrophobic fiber. 4. A composite heat-fusible fiber obtained by composite melt-spinning two or more thermoplastic polymers having different melting points as hydrophobic fibers. Item 7. The potentially bulky pulp composition according to item 8. 5. A method for producing a bulky pulp composition, comprising mixing pulp with hydrophobic fibers, reacting a crosslinking agent and fibrillating the mixture. 6. The process for producing a bulky pulp composition according to claim 5, wherein the crosslinking agent is reacted in the presence of a fiber softener. 7. The method for producing a bulky pulp composition according to claim 5, wherein the temperature at which the crosslinking agent is reacted is equal to or lower than the melting point of the hydrophobic fiber. 8. A composite heat-fusible fiber obtained by composite melt-spinning two or more kinds of thermoplastic polymers having different melting points as a hydrophobic fiber. The method for producing a bulky pulp composition according to the above item.