JPS59172566A - Paste and production thereof - Google Patents

Abstract

PURPOSE:To produce inexpensively a paste having excellent adhesion, tack, film-forming properties, moisture resistance, etc., by culturing a pullulan-producing strain in a medium contg. roasted dextrin as a carbon source. CONSTITUTION:A pullulan-producing strain (e.g. Pullularia pullulans AHU9533) is cultured in a medium (conventional nitrogen source and inorg-salts may be used) contg. roasted dextrin (degree of hydrolysis: 0.5-20) as a carbon source at an initial pH of 5-7.5 and at 22-30 deg.C for 5-8 days to produce pullulan having an MW of 10<3>-10<6>. The cultured medium is sterilized by heating, filtered, concentrated, dried and powdered to obtain a paste (the preferred ratio of produced pullulan to roasted dextrin is 7:3-3:7 by weight).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a rewetting propellant, a caking agent, and a composition obtained by culturing pullulan-producing bacteria in a medium containing roasted dextrin as a carbon source. The present invention relates to a paste with excellent adhesive strength, caking strength, and film properties, which is suitably used as a paste for di-fiber production, and a method for producing the same.

Conventionally, roasted dextrin has a significantly low viscosity of the size liquid, and the stability of the size liquid improves depending on the degree of decomposition, and those with a high degree of decomposition are completely soluble in cold water.1 Adhesive power1 Caking power (High temperature and strong) Taking advantage of these characteristics, we can produce paper products, stamps, labels, duct tape, transfer paper, sand molds for castings,
It is used as a carbonizing agent for electric welding rods, grindstones, plasterboards, and paints, as a diluent for medicines, dyes, and enzymes, and as a sizing agent for finishing textiles and printing.

In addition to the above-mentioned properties, roasted dextrin also has the cost advantage of being cheaper than other sizing agents (e.g., polyvinyl alcohol, gelatin, glue, gum arabic, pullulan), and its durability. Mildew resistance, moisture resistance and brittleness of coatings, carrability of coated paper.

There is a problem with the compatibility etc.

On the other hand, pullulan has a low viscosity as a paste, dissolves very well in cold water, has good adhesion and cohesive strength, and has a film that is moisture resistant and not brittle. However, because it is more expensive than other adhesives, it is currently hardly used in the industrial field.

Normally, pullulan is produced by aeration culture using the production strain for 5 to 8 days in a liquid medium containing sucrose, glucose, or starch partial hydrolyzate (patent application 1979-79413) that has been hydrolyzed with enzymes or acids in a wet manner. It is obtained by separating and purifying pullulan produced from the culture key solution.

However, it is difficult to obtain pullulan in high yield in a short period of time, and after 46 days, the enzyme is inactivated by heating, the bacterial cells are removed, and an organic solvent such as methanol is added in an equal amount or more. In addition, pullulan powder was obtained by precipitating pullulan, collecting it, dissolving it in water, repeating the same precipitation, purification, and drying, making it very expensive.

The inventors of the present invention have made extensive efforts to obtain a sizing agent that has good adhesive strength, caking strength, film properties, and moisture resistance, and is also inexpensive. It was discovered that a sizing agent whose main component is a composition obtained by culturing pullulan-producing bacteria in a medium containing pullulan is optimal and superior to a simple mixture of pullulan and roasted dextrin, and the present invention was completed. I ended up doing it.

Roasted dextrin used as a carbon source for the culture medium)
Natural starch obtained from wheat, rice, tapioca, sago, etc., amylose and amylopectin fractions, cross-linked starch, etherified starch, esterified starch, oxidized starch, acid-treated starch, etc. are used as raw materials and heated with a small amount of mineral acid. White and colored dextrins obtained by the process and acid-free or alkaline-expressed pretty gums are used.

Roasted dextrin) II has a special feature in that it can be obtained not only through a wet acid hydrolyzate or a mere 110 water decomposition reaction such as enzyme-modified dextrin, but also through a transfer reaction and a recombination reaction of cut molecules. , wet hydrolyzate, enzyme-modified dextrin) It differs from IIin in its molecular structure and properties.

The roasted dextrin used by the present inventors can have a hydrolyzed freshness (hereinafter abbreviated as DE, expressed as a value calculated by adding reducing sugar value to dextrose) of 0.5 to 20. The concentration at which this roasted dextrin is used in the culture medium is between 5 and 40%, preferably between 15 and 30%.

Other nitrogen necessary for the culture medium is commonly used nitrogen or inorganic nitrogen. Inorganic salts may also be used, such as known salts. That is, potassium phosphate, sodium chloride, magnesium sulfate, iron sulfate, etc. are used.

Any strain capable of producing pullulan can be used as the pullulan-producing strain.
pullulans AHU 9553, Pullulans
aria pullulans I F O6353,
Dematium pullulans I F O4
464, Aureobasidium pullula
Many strains such as nsrr06401 and 6402.6353 can be used.

During cultivation, the initial pH is adjusted to 5.0 to 7.5, the culture temperature is adjusted to 22 to 30'C+Ca, and aeration and stirring are carried out by a conventional method. The required culture time is usually 5 to 8 days, but in the present invention, the culture is carried out at a higher Km degree than usual, and the remaining roasted dextrin can be effectively utilized, so the required culture time is reduced to 3 to 8 days.
It can be shortened to 5 days.

After culturing, it is usually necessary to heat the culture solution to inactivate enzymes, remove bacterial cells, decolorize, concentrate, and separate and purify using an organic solvent. When used, the culture solution can be heated to inactivate the enzyme, sterilized, and left as is, or if necessary filtered, agglomerated, and powdered by one method such as drum drying, spray drying, or organic solution hinge precipitation. .

The pH of the glue solution of the present invention is 3-8, and the viscosity is 10'-10.
'cps (15% aqueous solution, 30°C, B-type rotational viscometer), the molecular weight of the produced pullulan is 17-10.

The ingredients in the glue of the present invention are the produced pullulan, the remaining roasted dextrin, and other things (dextrin that has been denatured and has a different structure from the roasted dextrin used in the medium, monosaccharides, enzymes). It is thought that pullulan, which has a different structure from the pullulan produced when modified dextrin and acid-saccharified starch syrup is used as a carbon source, is produced as a by-product.), and the main components are pullulan and roasted dextrin. Although the ratio varies depending on the culture conditions, it falls within the range of pullulan:roasted dextrin=7:3 to 3 (weight ratio). Furthermore, it has been found that the sizing agent of the present invention has lower adhesive strength and caking strength than a mixture of pullulan and roasted dextrin in these ratios, and also has a lower manufacturing cost.

The adhesive of the present invention has good adhesive strength, caking strength, film properties, moisture resistance, etc., and is therefore used in paper making, stamps, labels, gummed tape, transfer paper, foundry sand molds, electric welding rods, grindstones, ceramics, gypsum boards, etc. It can be effectively used as an adhesive for paints, a sizing agent for finishing or sizing fibers, and a coating binder for paper manufacturing.

Next, the present invention will be explained in more detail with reference to Examples.Example 1 In the production of the sizing agent of the present invention, Dematium pul
lulans IFO4464 strain, we used sucrose, glucose, acid-saccharified starch syrup (DE45), and roasted dextrin (D E O, 7, 5, 10, 17) as urea sources to examine the effects of the type of carbon source and culture time. .

The composition of the medium used was 20.0% carbon source, HP840.
2%, Naclo, 2%, peptone 0.4%, MgSO
47HA0.04 <,Pet04.7Ha0 0.0
01%, initial pH 7.5, roasting temperature 2B'
C. Culture time 3.4.5 days, rotary shaker.

Table 1 shows the yield of pullulan produced (9/l).

In addition, as a result of measuring the molecular ambiguity of pullulan obtained by gel filtration method, the one obtained from sample number 1 and 6 in Table 1 is approximately 10', and the one obtained from sample number 5 is approximately ]07, sample number 4 is about 10',
Sample number 3 was 10'.

(Unit: Da//) Example 2 The culture solution obtained in Example 1 (sample numbers 1 to 6) was heated to inactivate the enzyme, sterilized, filtered, and concentrated to make a 25% paste solution 1
For comparison, commercially available pullulan (Molecular Tube 300,000), roasted dextrin (DE3), and 25% sizing solution of a mixture of pullulan and roasted dextrin (IJ) in a ratio of 7:3 were used. Adhesion test was conducted under the following conditions using each glue solution on high-quality kraft paper for 3 Q mX
60 rrrn Cut one end of 30mm x 3mm
The paste was applied so that 30p of glue solids per rice cake.

5. After application, leave it for 120 seconds, overlap one end of 30wn x 60 sheets of kraft paper on the shelf and glue it, and after adhesion 10.
The adhesive force was measured after being left for 20 seconds.

The results are shown in Table 2.

(Unit: g) Example 3 Using the size liquid sample of Example 2,
09/d, dried at 70'C for 1 hour, kept at equilibrium in a constant temperature and humidity room at 20'C and 65% RH for 1 day, and then the same procedure as in Example 2 was carried out. 30 shoulders x 60
Cut it into pieces of 30 mm x 30 mm, wet the glue side of one end with water, leave it for 2.5.10 seconds, overlap one end of the same shape of kraft paper 30 my x 30 mm, and press it with a 5009 front die. 5. The adhesive force was measured after being left for 10 seconds. The results are shown in Table 3.

Table 3 (Unit: y) Example 4 1% of the sample used in Example 2 was added as a binder to the returned powder, which is the raw material for briquettes, and a briquette with a diameter of 30 m and a height of 10+++ m was prepared at a moisture content of 17% and a pressure of 1 ton. After molding into a cylindrical shape, 100
After drying in CIc for 1 hour, it was maintained in an equilibrium state for 1 day in a constant temperature and humidity chamber at 20'C and 65% RH, and then the fracture strength was measured using a Tensilon type testing machine.

The results are shown in Table 4.

Table 4 Then, cotton canvas and cotton broadcloth were soaked, squeezed once with a mangle, and dried at 100'C for 5 minutes.

The obtained starched cloth was subjected to a bending test (J, IS-L
-1096, Method A) was performed. The results are shown in Table 5.

Table 5 (Unit 'an) As is clear from the results of the above examples, the sizing agent of the present invention has adhesive strength, caking strength, and fiber hardening effect that are superior to pullulan, roasted dextrin, and mixtures thereof. ■I was told not to do anything.

Claims (2)

[Claims] (1) A sizing agent whose main component is a composition obtained by culturing a pullulan-producing strain in a medium containing roasted dextrin as a carbon source. (2) A method for producing a sizing agent, which comprises culturing a pullulan-producing strain in a medium containing roasted dextrin as a carbon source.