JPH04185792A - Latent bulky pulp composition and method for preparing the same - Google Patents

Abstract

PURPOSE:To prepare the subject composition having excellent moldability and processability retaining the strength, and giving sheets preserving the characteristic properties of cellulosic fibers such as the liquid-absorbing property and moisture-absorbing property by blending pulp with hydrophobic fibers, reacting the blended product with a crosslinking agent and subsequently opening the crosslinked product. CONSTITUTION:5-95 pts.wt. of pulp and 95-5 pts.wt. of hydrophobic fibers (preferably containing conjugated thermally fusible fibers obtained by melt-spinning two kinds or more of thermoplastic polymers having different melting points, respectively, into conjugated fibers) are blended, made to react with a crosslinking agent, preferably at a temperature below the melting point of the hydrophobic fibers, and subsequently opened to provide the objective composition.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a sheet and a sheet that have excellent bulkiness, moldability and processability, maintain strength, and retain the excellent properties of cellulose fibers such as liquid absorption and hygroscopicity. This provides a preferred material for making mats.

[Prior art and its problems]

A technique for making pulp bulky by subjecting it to a crosslinking reaction with formalin or the like is known, but if you try to improve the bulkiness of pulp in this way, it has the disadvantage that it becomes short fibers when disintegrated after crosslinking. In order to avoid this, there is a technology that attempts to make defibration easier by attaching a defibrating agent to the pulp in an amount of 1% or more, and although it is speculated that pulp-based bulky nonwoven fabrics may be used, crosslinking reaction The number of hydroxyl groups decreases due to the increase in hydroxyl groups, and therefore the amount of hydrogen bonds involving water decreases.Also, due to its bulk, there are fewer bonding points, so even if it is made into a single sheet, the sheet strength will drop significantly even though it has excellent bulk. However, there is no moldability or processability, and a sheet of a practical level cannot be obtained.

However, as in the conventional embodiments contrary to the present invention, bulky sheets produced by mixing chopped heat-fusible fibers and a hot water-soluble fibrous binder have high bulkiness, moldability, and functionality. It is expected to have many uses.

However, in this case, if heat-fusible fibers with a light specific gravity are used, mixing with pulp fibers during paper making becomes a problem and it is difficult to obtain a uniform fiber.

On the other hand, when pulp is crosslinked and defibrated, depending on the crosslinking conditions, the pulp becomes 10 times or more bulkier than uncrosslinked pulp under no load. Although this material can be pressed to reduce its thickness, there is another problem in that it requires a great deal of cost to store and transport.

[Problem that the invention seeks to solve]

The present inventor conducted extensive research on the above-mentioned technical problems related to bulky pulp compositions. As a result, the use of specific hydrophobic fiber chops in place of heat-fusible fibers and hot-water soluble characteristic binders results in latent bulking compositions that eliminate all of the above-mentioned properties. Based on this knowledge, the present invention was completed.

As is clear from the above description, the purpose of the present invention is to create a crosslinked pulp that is easy to defibrate, is convenient to store and transport, and has excellent mixability with the binder fibers of the heat-fusible fiber base during paper making. The object of the present invention is to provide a potentially bulky pulp composition that is not bulky per se but easily becomes bulky by defibration, and a method for producing the same.

[Means for solving problems]

The present invention is intended to achieve the above goals, and the gist thereof is as follows. That is, the pulp composition of the present invention is (1) a latent bulking pulp composition obtained by reacting a crosslinking agent with a mixture of pulp and chopped hydrophobic fibers, and (2) in reacting the crosslinking agent. (3) The reaction temperature of the crosslinking agent is below the melting point of the hydrophobic fiber used; (4) Hydrophobic Preferred fibers include composite heat-fusible fibers obtained by composite melt-spinning of two or more types of thermoplastic polymers having different melting points.

A mixture of chopped pulp and hydrophobic fibers reacted with a cross-linking agent in the presence of a fiber softener produces a paper-like, sheet-like or mat-like material with a specific gravity similar to that of a mixture of ordinary pulp and hydrophobic fibers. It can be stored and transported without any problems, but it often increases costs.

It is extremely easy to interpret this underwater.

This is due to the fact that the hydrophobic fibers prevent firm adhesion due to hydrogen bonds between pulps, and the softener of the fibers improves the sliding between pulp fibers and hydrophobic fibers, making it easy to defibrate and have a flexible, bulky composition. can get things. However, it is necessary to maintain the reaction temperature of the crosslinking reaction at a temperature lower than the melting point of the fibers used in the mixture. If the temperature is near or above the melting point, the hydrophobic fibers will fuse and become difficult to dissolve, which is contrary to the purpose.

The hydrophobic fibers according to the present invention have poor affinity with water, and do not dissolve or swell upon contact with water. Such fibers include polyurethane fibers, polyesters, polyamides, Polyimide-based, polyacrylic-based, etc. that do not have hydrophilic groups in their molecules can be used.

Furthermore, the hydrophobic fibers produced using heat-fusible fibers alone or in combination can be used to produce sheets or mats as they are after resolution or by mixing them with pulp or other fibers. These can be partially melted by heating to increase sheet strength while maintaining bulkiness, and can be molded and processed by heat sealing, embossing, etc.

Specific examples thereof include polyester fibers and polyamide fibers, and particularly preferred are fibrillated polyolefin-based synthetic valves developed for paper manufacturing. More preferred is a composite heat-fusible fiber made of two or more types of polymers having different melting points.

When heat-sealing, embossing, or other forming processing is performed on a sheet or Hammat produced by blending the composite heat-fusible fibers, the heating temperature should be lower than the softening point of the high-melting point polymer in the fibers, but lower than the softening point of the low-melting point polymer. By processing at a temperature higher than the softening point, a portion of the low-melting point polymer melts, and the composite heat-fusible fibers are bonded to each other, making it easier to perform embossing. In this case, the high melting point polymer fiber does not change its shape and contributes to maintaining the strength of the sheet itself, and the part that is not heated during embossing maintains its bulk by the bulky valve, so it is bulky, has excellent embossability, is strong, and has decorative properties. A cellulose-based bulky sheet with excellent properties can be obtained.

Therefore, by mixing the required amount of composite heat-fusible fibers in advance, or by mixing and crosslinking more than the required amount, products such as valves and other N1. A mixture of fibers can be used to produce the desired sheet or mat.

There are many composite heat-fusible fibers made by combining two or more types of polymers with different melting points, and there are many ways to combine the polymers and manufacture the fibers, and as long as the fiber surface is hydrophobic, they can be used as the subject fibers of the present invention. can.

As a specific example, the first is polypropylene/polyethylene composite fiber (trade name: Chitsusovolibro ES fiber), and the melting point of the low melting point component is 135°C or lower! 71
Temperatures below 00° C. are also particularly desirable for such purposes.

In addition, polyester/low melting point polyester, polyester/low melting point polyester, polypropylene/'low melting point ethylene-acid picopolymer, nylon 66, ・'nylon 6, nylon 6,/polyethylene, polyester 7
/Nylon 6 etc. can be used in the same way.

As the fiber softener in the present invention, softeners, softening agents, and smoothing agents that are commonly used in the textile industry can be used. These reduce the frictional resistance of the fiber surface and make it slippery, making it easier to defibrate, and since the product has a crosslinked structure, it becomes soft and supple, although it is originally hard.

These softeners include cationic, anionic, amphoteric, and nonionic softeners, and cationic softeners have the ability to reduce the coefficient of friction on the fiber surface well, so they are well suited to the purpose of the present invention.

CH, CHOH RCONHCH, CH, -N-CH, CH! 0HC=O
- There are quaternary ammonium salt types such as CM, C00H R, C0NHCH, CH, -N-CH, CH, OH, amine salt types, and amide types. When the product is intended to be water-absorbing, it is desirable to use an anionic, nonionic or amphoteric softener.

In addition, fabric softeners that are commercially available for household use and are used during laundry are also effective.

A sufficient effect can be obtained with an adhesion of 0.1% or less of the softener used. Since it can usually be used with an adhesion amount of 0.05% or less, it is preferable that the COD or BOD load on the drainage water is light when fiberizing and making paper.

The cross-linking reaction gives bulk to pulp,
It has two or more functional groups in its molecule that react with cellulose, and these are fixed in the crimped shape of the pulp through intramolecular or intermolecular crosslinking of cellulose, resulting in bulkiness and excellent dimensional stability. It is estimated that.

The chemical structure of the crosslinking agent is one that has at least two or more atoms between functional groups and reacts with methylol, alkoxymethyl, aldehyde, isocyanate, epoxy, vinylcarboxylic acid, acid anhydride, and other hydroxyl groups of cellulose. It has multiple.

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

More preferably, it has a cyclic structure between the crosslinkable functional groups. In particular, compounds having an N-methylol group as a crosslinkable functional group are highly reactive and preferred. The same applies to alkoxylated N-alkoxymethyl compounds for stabilizing and/or controlling reactivity. Specific examples include:

These include dimethylol ethylene urea, dimethylol dihydroxyethylene urea, dimethylol propylene urea, dimethylol uron, (tetra, tri, di) methylol acetylene diurea, (tetra, tri, di,) methylol melamine, and the like.

When these N-methylol compounds are used, a trace amount of formalin is produced when treated at high temperatures or at a pH other than specified. As a countermeasure to this problem, there is a method of suppressing free formalin by using a formalin scavenger.

Moreover, the problem can be solved by using a non-formalin-based crosslinking agent. As such, epoxy compounds such as ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, glycerol diglycidyl ether, nopeneopentyl glycol diglycidyl ether, dihydroxyethylene urea, and 1.3 dimethyl derivatives are effective.

The amount of these crosslinking agents to be used is preferably 2% or more by weight of the bulb, and preferably 50% or less.

The method for producing the latent bulky valve composition of the present invention includes a crosslinking agent,
Bulbs and hydrophobic fiber chops are mixed and stirred uniformly in an aqueous solution containing a catalyst and a fiber softener, squeezed so that a predetermined amount of crosslinking agent is attached, and then dried and heated to undergo a crosslinking reaction.

Here, the term "chopped" refers to short fibers obtained by cutting long fibers into lengths of 11 or less, preferably several lengths.

The mixing ratio is 5 to 95 parts of bulb to 95 to 5 parts of hydrophobic fiber, preferably 20 to 20 parts by weight.

The product is in the form of a sheet, mat, or lump, depending on the drying and crosslinking reaction equipment, but the specific gravity is similar to that of a normal valve system, and there is no bulkiness, and there are no problems such as increased storage and transportation costs.

This material can be easily defibrated by performing a normal defibration operation when manufacturing a bulky sheet, and an extremely bulky bulb can be obtained. In addition, when manufacturing by mixing bulky cross-linked bulbs and heat-fusible fibers in order to maintain processability, heat-fusible fibers are mixed as the hydrophobic fibers of the present invention and processed at a temperature below the melting point. By subjecting it to a crosslinking reaction, it can be defibrated and used as it is, or it can be mixed with bulb or other fibers to make paper to produce a sheet with excellent processing and forming properties such as heat-sealability and embossability.

Normally, when making paper by mixing chopped bulbs and heat-fusible fibers, it is difficult to mix them uniformly because they are used in a diluted state. To avoid this, efforts are being made to prevent separation by devising mixing methods and using special surfactants.

The composition according to the present invention makes it easier to homogenize the heat-fusible fibers used in the bulb and makes them difficult to separate, compared to the case where they are mixed during the preparation of the sort. This property becomes even more remarkable when a crosslinking reaction is carried out on a fibrillation operation of a uniform mixture of bulbs and chopped heat-fusible fibers, ie, hydrophobic fibers.

The composition of the present invention is preferably used in combination with a papermaking method, and after being resolved in water and dried, it can be used as a raw material for a bulky sheet or mat by a dry method to achieve homogeneous and excellent processability. A cellulosic bulky sheet or mat can be obtained.

[Function and effect]

According to the present invention, it is preferable for storage and transportation as a manufacturing raw material for the cellulose-based high-density sheet, and it is preferable for making paper containing heat-fusible fibers that easily become bulky during use and make the bulky sheet excellent in processability. The resulting composition can be widely used as nonwoven fabrics and functional papers.

Example 1 (Production) Softwood pulp and polypropylene/polyethylene composite heat-fusible fiber (Chisso Polyprofiber ES chop 3 denier, cut length 5 tat, manufactured by Chisso ■) were taken at a ratio of 8=2 and treated in the following treatment solution at home. The mixture was disintegrated and mixed using a small mixer.

Treatment liquid composition Dimethyloldihydroxyethyleneurea 5 parts Zinc nitrate 0.5 parts Dialkyldimethylammonium chloride 0.02
Part (Miyoshi oil ■ Epocol 5D-75) water
After mixing 94.5 parts, suction FA is squeezed using a glass funnel until the squeezing rate is approximately 2/1 (
This was dried at 100°C for 1 hour, and then reacted by heating at 115°C for 20 minutes to obtain a latent bulky sheet. The thickness was almost the same as that of one treated in the same manner without a crosslinking agent (uncrosslinked system).

(evaluation) 0 This material was defibrated in water using a household mixer.

When the rotational load of the mixer was adjusted to 40 V with a slider and defibration was performed with weak stirring, the time required for defibration of 90 cycles or more was within 20 seconds.

After defibration, the sample was suctioned and filtered using a glass funnel while being slightly compressed to obtain a sheet-like sample, which was then dried.

The weight increase of this product was 11.3% based on the pulp used, and the thickness was measured without a load and was 10.5 times that of one that was similarly treated without a crosslinking agent.

(Sheeting) Bulky crosslinked pulp composition 97 obtained above
and polyvinyl alcohol fiber (PVA binder ff
& VP1o made by Kuraray ■! 5-2) 3 parts of polyacrylamide as a dispersant (PAM manufactured by Tetsu Seikagaku ■)
) was used to prepare paper stock by dispersing it in water. The crosslinked pulp and ES fiber chops remained uniform without separation during paper stock preparation.

This was made into paper using a Tarabee standard sheet machine and dried using a Yankee dryer to obtain a bulky sheet.

The basis weight was set to 200g/m''.The thickness was measured and JI
A tensile test was performed according to SP81.13 to measure the tear length. The sheet manufacturing conditions, tensile tests, and other measurement results are shown in the table.

Comparative Example I A crosslinking reaction was carried out in the same manner as in Example 1 except that the ESfJt fibers were not chopped and no softener was added. The fibrillation property of the product is 12 when the rotational load of the mixer is 40V Slydac.
Even for 0 seconds, the fibers in the defibrated state had a modulus of 50 or less. 80V
A bulky crosslinked pulp was produced by increasing the load, defibrating, filtering and drying.

The weight increase was 9.8 times as much as the pulp used, and the thickness was 10.2 times that of the same treatment without a crosslinking agent when measured without a load.

97 parts of the bulky crosslinked pulp obtained above and PV
A paper stock was prepared by dispersing 3 parts of A binder fibers in water using PVM as a dispersant. This was made into paper using a Tarabee semi-standard machine and dried using a Yankee dryer to obtain a bulky sheet. A tensile test and other measurements were conducted in the same manner as in Example 1.

The sheet manufacturing conditions, tensile test and other measurement results are shown in the table.

Comparative Example 2 A paper stock was prepared by dispersing 77 parts of softwood pulp, 20 parts of ES chops, and 3 parts of binder fiber in water using PAM as a dispersant. In this case, when mixing and stirring, ES
Since the chops were easily floated and separated by incorporating air bubbles, the agitation speed was slowed down and a homogeneous state was made into a paper using a Tarabee semi-standard machine, dried using a Yankee dryer to obtain a sheet, and tensile testing was carried out in the same manner as in Example 1. @ was measured. The sheet manufacturing conditions and the measurement results of tensile test performance are shown in the table.

Example 2 A potentially bulky pulp composition was produced and evaluated in the same manner as in Example 1, except that the ratio of softwood pulp and ES chop was 85:15, and the treatment liquid had the following composition. The results are shown in the table.

Treatment liquid Dimethylol dihydroxyethylene urea 10 parts Zinc nitrate 1 part Polyamine/polyamide type softener 0.02 parts (Hisoflon MX manufactured by Miyoshi Yushi ■) Water 89
Furthermore, a bulky sheet was produced in the same manner as in Example 1, and its tensile test performance was measured. 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 the ratio of softwood pulp and ES chop was 85:15 and the treatment liquid had the following composition. The results are shown in the table.

Treatment liquid Tetramethylol acetylene diurea 5 parts Zinc nitrate 1 part Epocol 5D-750.02 parts Water 94
Furthermore, a bulky sheet was obtained in the same manner as in Example 1, and its tensile test performance was measured. 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 the ratio of softwood pulp and ES chop was 85:15 and the treatment liquid had the following composition. The results are shown in the table.

Treatment liquid glycerol diglycidyl ether 10 parts Z
n (BF4)! 2 parts Epocor 5D-75 0.02 parts water
88 parts A bulky sort was further obtained in the same manner as in Example 1, and the tensile test ability was measured. The results are shown in the table. Example 5 Same as Example 1 except that the ratio of softwood pulp and polypropylene fiber (P-chop manufactured by Chisso ■) was 80:20, the treatment liquid was as follows, and the reaction temperature was 120°C for 15 minutes. Similarly, a potentially bulky pulp composition was produced and evaluated. The results are shown in the table.

Treatment liquid dimethylol dihydroxyethylene urea 5 parts zinc nitrate 1 part water 94
Section Example 6 A potentially bulky pulp composition was produced and evaluated in the same manner as in Example 5, with a ratio of softwood pulp and P chop of 70:30 and the following treatment solution.

The results are shown in the table.

Treatment liquid Dimethylol dihydroxyethylene urea 10 parts Zinc nitrate 1 part Water 89 parts Example 7 A potentially bulky pulp composition was prepared in the same manner as in Example 5 using the following treatment liquid with a ratio of softwood pulp and P chop of 80:20. Manufactured and evaluated.

The results are shown in the table.

Processing liquid

Claims (8)

[Claims] (1) A latent bulky pulp composition obtained by reacting a crosslinking agent with 100 parts by weight of a mixture of 5 to 95 parts by weight of pulp and 95 to 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 potentially bulky pulp composition according to claim (1), wherein the temperature at which the crosslinking agent is reacted is below the melting point of the hydrophobic fibers. (4) Claim (1) characterized in that the hydrophobic fiber contains a composite heat-fusible fiber obtained by composite melt-spinning of two or more types of thermoplastic polymers with different melting points.
The potentially bulky pulp composition described in Section 1. (5) A method for producing a bulky pulp composition, which is produced by mixing pulp and hydrophobic fibers, reacting with a crosslinking agent, and defibrating the mixture. (6) A method for producing a bulky pulp composition according to claim (5), which comprises reacting a crosslinking agent 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 below the melting point of the hydrophobic fibers. (8) Claim (5) characterized in that the hydrophobic fiber contains a composite heat-fusible fiber obtained by composite melt-spinning of two or more types of thermoplastic polymers with different melting points.
A method for producing a bulky pulp composition as described in 1.