JPS6020520B2 - Method for manufacturing binder for papermaking - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for producing a papermaking binder, and more specifically, to a method for producing a papermaking binder using a substance obtained by reducing the molecular weight of chitin or its derivatives as a raw material. be.

When producing thin molded articles such as paper and nonwoven fabrics by papermaking methods from synthetic pipes, synthetic fibers, or mixtures of these and natural pulp, binders are used to impart adhesive strength to these fibers. Until now, this binder has been used, for example, acrylic resin, vinyl acetate resin,
Synthetic resins such as vinyl chloride resins, SBR, NBR, M
Synthetic rubbers such as BR have been used, but dialdehyde starch and polyvinyl alcohol have been particularly preferred because they are soluble in hot water. Each of these binders is appropriately selected depending on the purpose of use of the paper or nonwoven fabric, but when paper or nonwoven fabric is used in direct contact with the human body, all of these binders may cause irritation to the human body such as itching and rashes. It was unsuitable for medical use because it caused a rejection reaction. The present inventors aimed to develop a papermaking binder that can overcome the drawbacks of conventional binders and provide paper and nonwoven fabrics that can be used for medical purposes.As a result of extensive research, we have discovered that chitin or its derivatives It was discovered that a binder suitable for the purpose can be obtained as a raw material, and the present invention was completed based on this knowledge.

That is, in the present invention, low-molecular-weight chitin obtained by heating and dissolving chitin powder in dichloroacetic acid or a mixture of dichloroacetic acid and other organic solvent is suspended in caustic alkali in the presence of a surfactant, and then frozen. After melting,
The present invention provides a method for producing a binder for papermaking, which comprises alkylating the binder, then adding formic acid thereto to form a swollen and frozen yarn or granules.

Chitin is a type of polysaccharide consisting of amino sugars in which D-glucosamine, whose amino group is acetylated, is bonded to 8-1,4 glucosides. It is known to be more stable and less reactive than cellulose, which is widely available and has a similar chemical structure, and is insoluble in most inorganic and organic solvents.

In the method of the present invention, a low-molecular version of chitin is used. This low-molecular version can be achieved, for example, by adding chitin powder to dichloroacetic acid or a mixture of dichloroacetic acid and another organic solvent and dissolving it by heating. carried out by. next,
Low-molecular-weight alkylated chitin can be prepared by adding, for example, a solution of low-molecular-weight chitin obtained as described above at 12 psi in the presence of an alkali such as sodium hydroxide or potassium hydroxide and a surfactant. It can be obtained by freezing the compound at a temperature of -300° C. and then reacting it with an alkyl halide such as alkyl chloride or alkyl bromide at a low temperature such that no deacetylation reaction occurs after thawing.

Examples of this alkylated chitin include 0-methyl chitin, ○-ethyl chitin, 01n-propylchitin, ○-isopropylchitin, 01n-butylchitin, 0-isobutylchitin, 01te-butylchitin, 0-n-amyl chitin, 0- Examples include isoamyl chitin and 0-te-amyl chitin. To remove the alkylated chitin sutures in the method of the present invention, for example, the alkylated chitin obtained as described above is dissolved in a solvent such as dichloroacetic acid to form a solution, and this is placed in a coagulating liquid such as alcohol or ethyl acetate using a paper thread. This can be done by extruding through and solidifying.

Further, granules can be obtained by evaporating the solvent from the above solution and appropriately grinding the residue.
As the solvent in this case, in addition to the above-mentioned dichloroacetic acid and its mixture, formic acid and the like can also be used. In the present invention, when the binder is in the form of short fibers, its thickness is 1 denier or more, preferably 5 denier or less, and the length is 3 denier or less. If the thickness is too large, the adhesive force will be reduced, and if the fiber length is too long, the dispersibility when added to the fibers will be poor, which is not preferable. On the other hand, in the case of a granular binder, the particle size is 1 Yanagi or less,
Preferably it is 0.5 ribs or less.

If the particle size is larger than one rib, the swelling or solubility in water will be insufficient, making it impossible to obtain the necessary adhesive force. The binder of the present invention is blended at a ratio of 10 to 10 parts by weight per 10 parts by weight of raw material fibers such as synthetic pulp or synthetic fibers, and is dispersed in water or other soot to form paper.

In this case, raw material fibers include, for example, rayon, acetate, nylon, polyester, voripinyl alcohol,
Synthetic pulps and fibers made of polyvinyl chloride, polypropylene, polyvinylidene chloride, etc., or mixtures of these synthetic pulps, synthetic woven strands, and natural cellulose fibers are used.

When producing paper and nonwoven fabrics from these fibers, sizing agents, pigments, and various other additives may be used together.
In the present invention, there is no problem in using these additives in combination with the binder of the present invention.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Low-molecular-weight chitin is suspended in a sodium hydroxide solution in the presence of a surfactant and frozen at 1:20 p.m.

After melting this at room temperature, te91butyl bromide and 12-14
7.0 parts by weight of tem-butyl chitin obtained by reaction at ℃ was added with formic acid. Add 8 parts by weight, swell, and then -20
Disperse the molecules by freezing at °C. A viscous dope was prepared by adding 10.4 parts by weight of dichloroacetic acid to the gel. This dope was then extruded through a platinum nozzle (0.1 x 5 capes) into the first coagulation bed of ethyl acetate, followed by the second coagulation bed of methyl alcohol, and then drawn in air at a drawing ratio of 1.1 It was stretched twice and cut into three breast lengths. This ten
Parts by weight of butyl chitin fibers 2 and 80 parts by weight of rayon fibers (1. phantom x 5 wind) were added to water and uniformly dispersed, and then paper was made according to JIS P8209 and air-dried. The obtained rayon fiber paper has a density of 0.31
It had a tearing length of 3.0 and a specific bursting strength of 2.8. Example 2 In the same manner as in Example 1, 2-amyl chitin fibers were prepared from chitin and 2-pentane bromide, and the fibers were cut into three pieces.

Claims (1)

[Claims] 1 Low-molecular-weight chitin obtained by heating and dissolving chitin powder in dichloroacetic acid or a mixture of dichloroacetic acid and another organic solvent was suspended in caustic alkali in the presence of a surfactant, and then frozen and thawed. A method for producing a binder for papermaking, which is then alkylated, followed by adding formic acid to the resulting mixture, subjecting it to swelling and freezing treatment, followed by spinning or granulation.