JPH0450394A - Silk pulp for papermaking, silk raw paper and production thereof - Google Patents

Abstract

PURPOSE:To obtain the subject silk pulp for woven cloth, decoration and handicraft having fineness with readily bending by cutting (waste) silk yarn and digesting with alkali. CONSTITUTION:Silk yarn produced from raw silk yarn or waste silk yarn generated in spinning process is cut to, e.g. 2.5mm and digested with alkali to afford the aimed silk pulp. Said silk pulp is mixed with paper mulberry pulp, MITSUMATA pulp or GAMPI pulp in a weight ratio of 1:0.3-0.7 to afford silk raw paper.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to foil silk base paper for textiles, silk pulp and silk base paper for paper making for decorative and handicraft purposes, and a method for producing the same.

<Prior Art> Conventionally, Nishijin-ori is a fabric in which the warp and weft are woven using a loom such as a hollow-pulling machine or a jacquard machine. In order to express the luxuriousness that is one of the characteristics of this textile, advanced techniques such as kinde, brocade, and karaori are required, and gold and silver thread, gold and silver leaf paper, and weft and ground texture of each color representing the pattern are woven. Latitude is used. Currently, foil paper and habutae are used to make these foil threads and wefts, which are made by mixing bast fiber pulp such as mitsumata and stratified fiber pulp.

After foil processing, the foil paper is cut into thin strips to make foil threads, but they have the drawback of being easily broken and lacking in the texture of silk.

Most of the uses of silk were limited to high-end clothing such as Japanese clothing, but recently it has become widely used as a material for Western clothing. In addition, research and development in new fields such as the development of raw silk and silk thread with new characteristics, composite technology of silk and other fibers, and new chemical processing technology for silk thread became active.

<Problem to be solved by the invention> Raw silk produced by silkworms such as domestic silkworms (also called silk silk) is made up of two fibroin fibers, although there are some differences between them.
It is a protein fiber to which sericin, which accounts for about 25% of the total, is stuck. However, in this state, high-quality yarn cannot be obtained by spinning, so either the raw silk is woven into warp and weft yarns, and then scoured after making a fabric, or the raw silk is first scoured to create warp and weft yarns. A weaving method is used.

In both cases, silk fabrics are made by scouring the raw silk and removing the sericin. Fibroin fibers that make up silk fibers differ from cellulose fibers in that they contain neutral glycine (Gl).
y), alanine (Ala), and serine (Ser) account for about 84% of the total amino acids, with a ratio of 4:3:1. Moreover, this fiber is (Gly-Ala-Gly-Ala-Gly-3e
r) Crystals in which n repeating structures are highly oriented occupy the main portion. The fibroin molecules that make up this fibroin are composed of two types of molecules with different sizes: one polymer M (molecular weight 350,000) and several low molecular chains with a relatively small molecular weight (250,000). Collectively, they form small crystal structures, with both chains held tightly together by sulfur-sulfur and hydrogen bonds. Furthermore, these small crystal structures come together to form fibroin fibers consisting of crystalline parts and amorphous parts, which form the bone structure of silk threads. Generally, the structure of oriented fibroin molecules in the crystal part is called the β-structure.

In addition, fibroin fibers contain small amounts of about 14 types of amino acids, which are said to bring about subtle changes in the properties and solubility of silk fibers.

Pulp fibers made by cutting silk threads are neutral and have a small amount of hydrophilic groups, so it is difficult for water to penetrate into the crystalline parts, and compared to cellulose natural fiber pulp, it is difficult to swell and has poor water retention. . In addition, silk pulp fibers, which are highly flexible fibers, tend to become entangled in water and are difficult to disperse uniformly, so even when paper is made, it is bulky and only paper with weak fiber-to-fiber bonds can be made. do not have.

Purpose The purpose of the present invention is to partially modify silk fibers to improve water retention and dispersibility, to produce silk pulp for papermaking, and to produce practical silk base paper that exhibits the texture of silk. At the same time, we are developing technology to produce silk pulp for papermaking and other natural fiber pulps,
(and) To obtain high quality silk base paper from mixed pulp blended with synthetic fiber pulp.

Means for Solving the Problems The means for solving the problems according to the present invention is to cut silk threads produced from raw silk or waste silk threads produced during the spinning process, and to obtain silk pulp for papermaking by alkali digestion.

Effect> In the above-mentioned means for solving the problem, by alkali-cooking cut silk threads or waste silk threads in, for example, a 0.7% caustic soda solution, silk fibers that are delicate, easily bent, and have relatively poor water retention properties can be produced. It is possible to obtain papermaking silk pulp with good dispersibility, and by adding paper strength enhancers and sizing agents to papermaking silk pulp or blended pulp with other pulps, it is possible to obtain silk pulp with good dispersibility. It is possible to make silk base paper that shows the combination.

<Example> Generally, in pulp fibers for paper manufacturing, the fiber length, the bonding area between fibers, and the bonding strength have a large influence on the strength of the paper. When paper is made with pulp fibers uniformly dispersed, the longer the fiber length, the greater the tearing length of the paper, but beyond a certain fiber length, the fibers become entangled even if a dispersant is used effectively. This results in a significant decrease in dispersibility. A similar phenomenon is observed in the case of silk pulp fibers; in order to produce silk base paper with uniform texture, it is necessary to cut silk threads to an optimal length to produce silk pulp for paper production.

Using five types of silk pulp with different fiber lengths (1 to 5 mm), the dispersibility of pulp fibers in water was determined from the measurement results of sedimentation velocity and sedimentation volume, and from the strength and formation of handmade paper. ,
It has been found that the fiber length of silk pulp for papermaking is best between 2.5 and 3.0 mm.

Silk pulp fibers cut to longer fiber lengths tend to become entangled, and even when paper is made using a dispersant, hand-made paper with good texture cannot be obtained. In addition, paper with lower strength can be made from silk pulp with shorter fibers.

Wet silk threads or waste silk threads produced in gaps during spinning are made into fiber bundles (
Even if handmade paper is made from silk pulp cut to 2.5 mm, it is difficult to make bulky and strong paper. To further improve paper strength and produce paper that exhibits the feel of silk, it is necessary to modify silk pulp fibers.

Silk fibers easily swell and dissolve in formic acid or concentrated solutions such as lithium bromide and calcium chloride. However, in these solutions, the β-structure of silk fibroin fibers collapses and easily changes to an amorphous α-structure, so a part of the fiber structure is modified to produce silk pulp for papermaking with high water retention. The use of these compounds in the production of is technically problematic.

Silk pulp for papermaking was produced by expanding the amorphous part of silk pulp fibers and cooking them using caustic soda, which improves the swelling and water retention properties of the fibers.

Cooking conditions using caustic soda were selected based on the results of measuring the yield and dispersibility of papermaking silk pulp and the strength of handmade paper2.
A yield of 75 to 80% was obtained by cooking silk pulp cut into 5 mm pieces in a 7% caustic soda solution at a liquid ratio of 1:16 kg/I at 70°C for 1 hour with occasional stirring.
of silk pulp for paper making is obtained. On the other hand, if the concentration of the caustic soda solution is increased or the cooking conditions are made harsher, the silk pulp fibers will dissolve and the pulp yield will decrease, resulting in a less strong paper with poor silk feel. The strength of handmade paper reaches a constant level at a pulp yield of 75-80%.

Subsequently, the pulp is beaten for 1 to 2 hours to promote fibrillation of the papermaking silk pulp fibers, and screened to remove mixed long fibers and bound fibers to produce carefully selected papermaking silk pulp.

The strength of handmade paper made from papermaking silk pulp is
g/m2, tensile strength 0.72 kg/15 mm, tear strength 3.47 g, bursting strength 0.743 kg/cm
2 still does not reach the target strengths. In addition, since the wet strength was extremely low at 0.065 kg/15 mm, we researched and developed a paper manufacturing method using a paper strength enhancer and a sizing agent.

Due to the electrical charge state of silk pulp fibers, we attempted to improve paper strength by using aqueous or colloidal solutions of cationic acrylamide polymers or ampholytic polymers. In addition, carboxymethyl cellulose is used to further improve the dispersibility of silk pulp fibers after using the paper strength agent.

The wet strength of silk base paper is improved by using an alkyl ketene dimer-based synthetic sizing agent that has a good sizing effect.

For example, Polystron PS311 manufactured by Hazuki Chemical Industry Co., Ltd. is effective as an acrylamide-based paper strength enhancer.
and Acostar C122 manufactured by Mitsui Cyanamid Co., Ltd.
However, synthetic sizing agents include Hazuki Kagaku Kogyo Co., Ltd.'s Size Pine 903 and Dick Vercules Co., Ltd.'s Size Pine 903.
Vercon 40 manufactured by J.D. Co., Ltd. exhibited good papermaking effects.

Polystron PS311 in an amount equivalent to 3 to 4% of the amount of papermaking silk pulp was dissolved in a large excess of water, added to the pulp suspension, and adsorbed, and then carboxylic acid in an amount equivalent to 0.15% was dissolved in a large excess of water. Add methylcellulose diluted in water to disperse the pulp fibers.

In addition, when using ampholytic electrolytic polymer colloid Acostar C122 as a paper strength enhancer, Acostar C122 equivalent to several percent of the amount of papermaking silk pulp is dispersed in a large excess of water and added to the pulp suspension. . In this case, since the dispersibility of pulp fibers is good, the synthetic sizing agent size pine that does not require the use of carboxymethyl cellulose is used with 90B and Barcon 40.
is 0.2 of the pulp amount after adding the above paper strength enhancer.
An amount corresponding to ~0.35% is dispersed in a large amount of water,
Add to pulp suspension.

The required amounts of paper strength enhancers and sizing agents vary slightly depending on the silk fiber and processing conditions, but should be determined based on the dispersion state of papermaking silk pulp in water and the strength and formation of handmade paper. It is recommended that you decide accordingly.

Silk pulp for papermaking can be blended with other natural fiber pulps and synthetic fiber pulps to produce silk base paper. Cord,
When bast fiber pulp such as mitsumata, laminar, kenaf, etc. or abaca pulp is blended with silk pulp, silk base paper with stronger paper strength can be obtained.

As the synthetic fiber pulp, rayon pulp, polyester pulp, nylon pulp, etc. can be used, but it is preferable to add a fibrous low melting point binder to the paper.

The amounts of paper strength agents and sizing agents required when making silk base paper by blending papermaking silk pulp with other pulps are based on the amounts needed when making paper using only silk pulp. It is calculated from the amount of silk pulp blended. In this case as well, the amount of additives to improve the papermaking effect varies slightly depending on the type of pulp, so the amount to be added must be determined in advance while considering the dispersibility of the blended pulp and the strength and formation of the handmade paper. It is necessary to keep

Next, the details of the present invention will be explained with reference to Examples.

(First Example) 300g of Chinese silk pulp cut into 2.5mm pieces was
4.81% 0.7% caustic soda solution heated to 0°C (
After the solution was well absorbed, alkaline cooking was carried out for 1 hour at the same temperature with occasional stirring. The pulp after cooking is washed with water and beaten for one hour using a small laboratory beater. Next, the mixture is screened (8/1000) to remove the long fibers present therein. The yield of the carefully selected papermaking silk pulp obtained in this way was 78%, which was almost the same as the yield of papermaking silk pulp when the waste silk produced from the spinning process was cut and alkali digested.

Subsequently, handmade paper is made from papermaking silk pulp or a mixed pulp that is a blend of this pulp and other pulps.

At this time, polystron PS3 equivalent to 4% of the amount of papermaking silk pulp was added to the pulp suspension (pulp concentration 0.25%).
11.0.15% carboxymethyl cellulose and 0.15% carboxymethylcellulose.
A dilute solution of 903 was added to 35% size pine in this order to disperse the pulp well, producing handmade paper with a basis weight of 60 g/m2.

Among handmade silk base papers made by blending other pulps, it has been found that silk base paper with good texture and strong strength can be obtained from gampi pulp or a blended pulp of mitsumata pulp and papermaking silk pulp. Ta. In this case, the paper strength agent and sizing agent are added in decreasing amounts depending on the amount of silk pulp in the blended pulp. Figure 1 shows the strength of handmade paper made from various blended pulps.

The measurements were performed according to JIS standards.

(Second Example) 150 kg of Chinese silk pulp with a fiber length of 2.5 mm was heated in advance to 80°C in a 0.7% caustic soda solution of 2400 kg.
1 (liquid ratio 1:16 kg/l) was added to a flat lid for cooking, and after uniformly dispersing the pulp, alkaline cooking was carried out at 70°C for 1 hour with occasional stirring. After washing with water, the silk pulp is beaten using a beater for 1 hour to promote fibrillation of the pulp fibers and increase water retention. Subsequently, mixed long fibers and impurities are removed using a flat screen equipped with an 8-cut screen, and then a wet sheet for papermaking is produced using a wet machine. The yield of the purified silk pulp obtained was 82%.

On the other hand, two types of bleached mitsumata pulp wet sheets produced by soda-digesting Chinese mitsumata white bark, calcium hypochlorite bleaching, and disintegration were used to produce two types of bleached mitsumata pulp with different blending ratios with papermaking silk pulp. Adjust mixed pulp. Silk base paper was then produced using a circular mesh paper machine according to the paper making process shown in FIG.

Polystron PS311, carboxymethyl cellulose, synthetic sizing agent Size Pine, 903 or Burcon 40 were added in amounts equivalent to 4%, 0.15%, and 0.35% of the silk pulp amount in the blended pulp, respectively. Dissolve and dilute in water and add to the pulp suspension at the location shown in Figure 2. In addition, a polyethylene oxide solution was used to facilitate the peeling of the silk base paper from the dryer.

The test results for the mechanically made paper are shown in Table 12 and Table 2.

Table 1. Test results for silk base paper (mixing ratio of papermaking silk pulp and mitsumata pulp 1:1) Table 2. Test results of silk base paper (mixing ratio of papermaking silk pulp and mitsumata pulp 7:3) Basis weight 52 g/m2 Basis weight 17 g/m2 Basis weight 49 g/m2 Note that the present invention is not limited to the above examples. Of course, many modifications and changes can be made to the above embodiments without departing from the scope of the present invention.

That is, the present invention includes the following technology.

(1) A method for producing silk pulp for papermaking, which comprises cutting silk threads produced from various types of raw silk or waste silk threads produced during the spinning process and alkali-digesting them to obtain silk pulp for papermaking.

(2) Silk pulp for papermaking produced by the method described in item (1) above.

(3) Silk base paper produced from a mixed pulp containing the papermaking silk pulp described in item (2) above and other natural fiber pulp or synthetic fiber pulp.

(4) The papermaking silk pulp described in item (2) above and the pulp, mitsumata pulp, or stratified pulp are combined in a ratio of 1:0.3 to 0.3 to 0.
．． Silk base paper characterized by being produced by mixing at a ratio of 7:1.

(5) The papermaking silk pulp described in (3) above and the polyester pulp or nylon pulp at a ratio of 1:0.25.
Silk base paper characterized in that it is produced by mixing at a ratio of ~0.7.

<Effects of the Invention> According to the present invention, cut silk threads or waste silk threads are alkali-cooked in, for example, a 0.7% caustic soda solution to produce delicate and easily bendable silk threads with relatively low water retention properties. Silk fibers can provide silk pulp for papermaking with good dispersibility.

Further, by adding a paper strength enhancer and a sizing agent to papermaking silk pulp or pulp mixed with other pulps, it is possible to make silk base paper that has the feel of silk.

Silk paper containing mitsumata pulp produced by the papermaking technology of the present invention has been highly evaluated as a foil paper used in Nishijin-ori. In addition, new uses for silk base paper have been found for textiles, decoration, and handicrafts.

[Brief explanation of the drawing]

FIG. 1 is a line showing the blending ratio of pulp in an example of the present invention, and FIG. 2 is a block diagram of the papermaking process. Applicant Miki Tokushu Paper Co., Ltd.

Claims (1)

[Scope of Claims] 1. A method for producing silk pulp for paper making, which comprises cutting silk thread produced from raw silk or waste silk produced during the spinning process and alkali-digesting it to obtain silk pulp for paper making. 2. Silk pulp for papermaking produced by the production method according to claim 1. 3. Silk base paper produced from a mixed pulp containing the papermaking silk pulp according to claim 2 and other natural fiber pulp or (and) synthetic fiber pulp. 4. Silk base paper produced by mixing the papermaking silk pulp according to claim 2 with kozo pulp, mitsumata pulp, or gampi pulp at a ratio of 1:0.3 to 0.7. 5. Silk pulp for papermaking according to claim 2 and polyester pulp or nylon pulp at a ratio of 1:0.25 to 0.7
Silk base paper characterized by being manufactured by mixing the following ratios.