WO1998033968A1

WO1998033968A1 - Amylopectin potato starch products as sizing agents for textile yarns

Info

Publication number: WO1998033968A1
Application number: PCT/NL1998/000063
Authority: WO
Inventors: Reinald Henk Huizenga; Jan Mantingh; Fenna Pomp-De Wit
Original assignee: Coöperatieve Verkoop- En Productievereniging Van Aardappelmeel En Derivaten Avebe B.A.
Priority date: 1997-01-30
Filing date: 1998-01-30
Publication date: 1998-08-06
Also published as: AU5884698A; NL1005141C2

Abstract

The invention relates to the use of chemically modified amylopectin potato starch products as sizing agent for sizing natural and/or synthetic yarns. The invention also relates to a process for sizing natural and/or synthetic yarns using chemically modified amylopectin potato starch products as sizing agent.

Description

Title: Amylopectin potato starch products as sizing agents for textile yarns .

The invention relates to the use of chemically modified amylopectin potato starch as sizing agent for natural and/or synthetic textile yarns and textile blended yarns as well as to a process for sizing textile yarns using these starch products .

In the weaving process, the warp yarn is subject to abrasion and to considerable differences of tension through cyclic stretching. As a result of stretching, the yarn has a tendency towards breaking. Abrasion causes fibers to partly get loose from the thread. These projecting fibers of different yarns can become entangled, which results in thread breakage. Breakage of the yarn decreases the efficiency of the weaving process. The material that gets loose during abrasion tends to fuzz formation. The resulting fuzz may be interwoven in the textile product, which is undesirable. The necessary removal of the loose textile material from the working accommodation increases the cost of weaving.

To overcome these problems and to increase the weaving efficiency, the warp yarn is sized. The warp yarn is sized by giving all the warp yarns lying parallel in one plane an immersion passage through a sizing agent solution. Subsequently, the yarn is pressed off to remove the excess size solution. Then the pressed-off yarn is dried on heated drums or by means of hot air. Finally, the dried yarns are split and wound on the warp beam which goes to the loom. In the sizing process, a film of the sizing agent is applied around the textile yarn. This film reinforces and protects the yarn. In the sizing process, the fibers projecting from the yarn body are also adhered to the thread. Consequently, the sized yarn becomes smoother, which results in less abrasion in the weaving process. Sizing agents are usually applied in combination with auxiliary agents, such as fats and washing products, which further improve the smoothness of the sized yarn.

Well-known water-soluble sizing agents are native starches, modified starches (physically, enzymatically and/or chemically modified) , polyvinyl alcohol, carboxymethyl cellulose and polyacrylates . Mixtures of these sizing agents are also often used. After the weaving process, the sizing agents are mostly removed from the textile fabric again. The sizing agent to be used must satisfy different requirements, such as good penetrativeness, good adhesiveness, good film-forming properties and the ability to form an elastic sizing film. A suitable sizing agent imparts to the sized yarn desirable properties, such as a high wear resistance (abrasion resistance) , a high weaving efficiency and good washing-out properties of the woven textile product. The use of the various chemically modified starch products as sizing agents for textile yarns has been extensively described by K.W. Kirby; Textile Industry, in the book by O.B. Wurzburg (Ed.): Modified Starches: Properties and Uses CRC Press Inc. Boca Raton, Florida, 1986, pages 229-252. Mentioned as chemically modified starches are: acid-modified starch, oxidized starch, crosslinked starch, starch ethers and starch esters. As starting material for the modification, the various types of starch may be used, such as maize starch, potato starch (with about 20 wt.% amylose), tapioca starch and wheat starch. It is an object of the present invention to provide a sizing agent on the basis of chemically modified starch that gives very favorable sizing properties, weaving properties of the sized yarn and washing-out properties of the woven cloth. It has been found that this object can be achieved according to the invention by using chemically modified amylopectin potato starch as sizing agent for natural and/or synthetic textile yarns. Hereinafter follows a brief explanation about amylopectin potato starch.

Most types of starch consist of granules in which two types of glucose polymers occur, viz. amylose (from 15 to 35 wt.%, based on the dry substance) and amylopectin (from 65 to 85 wt.%, based on the dry substance). Amylose consists of unbranched or little branched molecules of an average degree of polymerization of from 1000 to 5000 (depending on the type of starch) . Amylopectin consists of very large, highly branched molecules of an average degree of polymerization of about 2,000,000. The commercially most important types of starch, viz. maize starch, potato starch, wheat starch and tapioca starch, contain from 15 to 30 wt.% amylose.

Of some types of cereal, viz. barley, maize, millet, milo, rice and sorghum, there exist natural varieties, the starch granules of which consist substantially entirely of amylopectin. Calculated as weight percentage based on the dry- substance, these starch granules contain more than 95% and usually more than 98% of amylopectin. The amylose content of these cereal starch granules is therefore less than 5% and usually less than 2%. It has been found that, during the formation of amylopectin cereal starch granules in the cereal plant, the enzyme that catalyzes the synthesis of amylose molecules is absent . The above cereal varieties are sometimes referred to as waxy cereal grains and the amylopectin starch granules isolated therefrom as waxy cereal starches .

In contrast with the situation regarding various cereals, no potato varieties are known from nature the starch granules of which consist substantially exclusively of amylopectin. The potato starch granules isolated from potato tubers usually contain about 20% amylose and 80% amylopectin (wt.%, based on the dry substance) . In the past 10 years, however, successful efforts have been made to breed, through genetic modification, potato plants that form starch granules in the potato tubers, which consist as to more than 95 wt.% (based on the dry substance) of amylopectin. In the formation of starch granules in the plant, various enzymes are catalytically active. Of these enzymes, the granule-bound starch synthase (GBSS) is involved in the formation of amylose. The synthesis of the GBSS enzyme is dependent on the activity of genes that code for the GBSS enzyme. Elimination or inhibition of the expression of these specific genes leads to the synthesis of the GBSS enzyme being prevented or limited. The elimination of these genes can be realized through genetic modification of potato plant material. An example thereof is the amylose-free mutant of the potato (amf) , the starch of which contains substantially only amylopectin, due to a recessive mutation in the GBSS gene. This mutation technique has been described, inter alia, in the following two journal articles:

- J.H.M. Hovenkamp-Hermelink et al .

Isolation of amylose-free starch mutant of the potato

(Solanum tuberosum .)

Theor. Appl . Genet. (1987), 75: 217-221.

- E . Jacobsen et al . Introduction of an amylose-free (amf) mutant into breeding of cultivated potato, Solanum tuberosum L. Euphytica (1991), 53, 247-253.

Elimination or inhibition of the expression of the GBSS gene in the potato is also possible by the use of so-called antisense inhibition. This genetic modification of the potato has been described in Canadian patent 2,061,443; International patent specification WO 92/11376 and the following journal article: - R . G . F . Visser et al .

Inhibition of the expression of the gene for granule-bound starch synthase in potato by antisense constructs. Mol. Gen. Genet. (1991), 225: 289-296.

By the application of genetic modification it has been found possible to breed and grow potatoes the starch granules of which contain little or substantially no amylose. The term amylopectin potato starch is herein understood to mean the potato starch granules isolated from potato tubers, having an amylopectin content of at least 95 wt.%, based on the dry substance.

As regards production possibilities and properties, there are significant differences between amylopectin potato starch on the one hand and the waxy cereal starches on the other. This also holds, in particular, for waxy maize starch, which is commercially by far the most important waxy cereal starch. The growth of waxy maize, which is suitable for the production of waxy maize starch, is not commercially feasible in countries with a cold or temperate climate, such as the Netherlands, Belgium, England, Germany, Poland, Sweden and Denmark. However, the climate in the above countries is suitable for the growth of potatoes .

The composition and properties of amylopectin potato starch differ from those of the waxy cereal starches. For instance, amylopectin potato starch has a much lower content of lipids and proteins than the waxy cereal starches. Problems regarding odor and foam formation, which may arise because of the lipids and/or proteins when using waxy cereal starch products (native and modified) , do not occur, or do so to a much lesser extent, when use is made of corresponding amylopectin potato starch products . As opposed to the waxy cereal starches, amylopectin potato starch contains chemically bound phosphate groups. As a result, in dissolved condition amylopectin potato starch products possess a specific polyelectrolyte character. Chemically modified starches are herein understood to mean starch products obtained by chemically modifying starch through acid modification, oxidation, esterification, etherification, graft polymerization and/or crosslinking. Before, during or after the chemical modification a physical modification (for instance, through roller drying, extrusion or a heat-moisture treatment) or an enzymatic modification of the starch may also be carried out. Methods for preparing the various chemically modified starches have been described in the book O.B. Wurzburg (Ed.). Modified Starches: Properties and Uses; CRC Press Inc. Boca Raton, Florida, 1986. These methods can also be used for preparing chemically modified amylopectin potato starch used according to the invention as sizing agent. Aqueous solutions of these sizing agents, also referred to as sizing bath or sizing paste, may be made in the conventional manner, for instance in open or closed boiling apparatus . The treatment of the textile yarns with the aqueous solutions of chemically modified amylopectin potato starch products according to the invention can be carried out by the methods conventional for sizing yarns. The yarns can, for instance, be passed continuously through a solution of the sizing agent, or a solution of the sizing agent may be applied to the yarn by spraying or by means of a roller. After passing the sizing paste, the layer of yarn is pressed out, for instance between two rollers. Then the pressed-out yarns are dried on heated cylinders or by means of hot air.

To obtain a good penetration of the sizing agent into the yarn, the sizing bath is preferably kept at a temperature of from 30 to 90°C. The concentration of the sizing agent in the sizing bath is preferably between 2 and 20 wt.%. The amount of sizing agent absorbed by the yarn (absorption; weighting) is preferably between 2 and 30 wt.% of sizing agent (dry substance) based on yarn (dry substance) . Besides the chemically modified amylopectin potato starch, the sizing solutions to be used may further contain slight amounts of auxiliary substances conventional in the sizing process, such as waxes, fats, antifoaming agents, antistatic agents and plasticizers . The sizing solutions may additionally contain other sizing agents, such as polyvinyl alcohol, polyacrylates or carboxymethyl cellulose. It has been found that chemically modified amylopectin potato starch is very suitable as sizing agent for textile yarns. The yarns. sized according to the invention are well- resistant to mechanical influences (high wear resistance) in that they are coated with a strong, elastic, smooth covering. In the weaving mill, excellent results are obtained with these yarns (high weaving efficiency) .

As stated before, the invention relates to a process for sizing textile yarns. In this connection, the term yarns is herein understood in the most general sense and is deemed to comprise all threads or yarns occurring in the textile industry. They may consist of continuous threads or of fibers, be of a natural, semi-synthetic and/or synthetic type and be twisted or not twisted (SW 57) .

The invention will be further explained in and by the following examples. According to the examples the sized yarns have been examined for some characteristic properties . The figures set forth in this connection have the following meaning :

Absorption (weighting)

The absorption (weighting) is the amount of sizing agent (weight percentage) based on the unsized yarn according to the formula:

Weight before desizing - Weight after desizing x C

Absorption (%) =

Weight after desizing x C

Weight of control yarn before desizing

Weight of control yarn after desizing

Wear resistance

Sized yarn is stretched in the wear test apparatus. Then 50 samples are measured. During this measurement the yarn wears cyclically along itself until breakage. The number of strokes until breakage of each yarn is recorded separately, followed by calculating in what interval 95% of the samples breaks .

Washing-out properties

Test method:

A sample of unbleached cotton band is finished with a 10% sizing solution of the relevant sizing agent (wet absorption ca. 100%) . After drying (5 min. at 100°C) , it is washed out with the following solutions (95°C) : I - 2 g/1 soda II - 2 g/1 non-ionic moistener III - water

After each washing passage, the band sample is pressed off on the Benz foulard at a rate of 3.5 m per minute and a pressing-off pressure of 25 kg/cm. 6 sec . I

36 sec . II

15 sec . III

72 sec . II

15 sec . III

To the still wet sample band a 0.01 N iodine solution is applied dropwise. The stain is compared with a standard. From this it can be determined whether a product can be desized without the use of enzymes or oxidizing agents.

Weaving efficiency The weaving efficiency is herein defined as

Realized weaving time Weaving efficiency = x 100 %

Theoretical weaving time

Example 1

In this example, chemically modified starches on the basis of normal potato starch (21 wt.% amylose) and on the basis of amylopectin potato starch are compared with each other regarding the use as sizing agent. The chemically modified starches were prepared by extrusion of an alkaline reaction mixture of starch and monochloroacetic acid. Thus the following carboxymethylated extruded starch products were obtained: A. Carboxymethyl derivative of potato starch (AZM) having a DS (Degree of Substitution) of 0.13 (Commercial product

Quicksolan (MS of AVEBE)

B. A corresponding carboxymethyl derivative of amylopectin potato starch (AAZM) having a DS of 0.13 C. A carboxymethyl derivative of amylopectin potato starch having a DS of 0.08. Dissolving method

To 600 ml mains water was added the required amount of starch product. This was followed by boiling with steam while stirring for 20 minutes. Then the volume was supplemented to 1 liter, and stirring was performed for 1 minute with the Kotthoff mischsirene (at 2800 rpm) . Then the solution was heated to 85°C. After measuring the viscosity, the solution was used for sizing textile yarn.

Sizing

Cotton yarns (Ne 36/1; 25 threads) were sized (twice immersing; twice pressing off) on a laboratory sizing machine. The sizing temperature was 85°C, the pressing-off pressure 5 kg/3.5 cm and the drying temperature 140°C. The sizing rate was 50 m/min.

Evaluation of sized yarns

The sized yarn was conditioned at 20°C and 65% relative air humidity and then tested for weighting (absorption) and wear resistance. Table 1 gives the results of a number of recipes .

Table 1 Weighting and wear resistance

Carboxyme thy 1 Starch DS Weighting Limits starch on the product carboxy % wear rebasis of concentration methyl sistance in sizing paste 200/2 t..% cN

Potato 9 0.13 13.0 82-100 starch (AZM)

AZM 11 0.13 18.4 133-162

AZM 14 0.13 27.6 300-435

Amylopectin 12 0.13 17.8 126-155 potato starch (AAZM)

AAZM 12 0.13 17.2 151-186

AAZM 12 0.13 17.3 142-175

AAZM 12 0.13 16.0 131-165

AAZM 12 0.13 16.0 127-159

AAZM 12 0.13 15.1 119-148

These results are given in Figure 1, in which the wear resistance is plotted against the weighting. Table 1 and Figure 1 show that yarn sized with a carboxymethylated amylopectin potato starch (AAZM) , at equal weighting by sizing agent, has a better wear resistance compared to the same yarn sized with a corresponding derivative on the basis of normal potato starch.

Example 2

In this example it is demonstrated that the washing-out properties of carboxymethyl amylopectin potato starch, when the degree of substitution (DS) of carboxymethyl substituents falls from 0.13 to 0.07, does not decrease. A sample of unbleached cotton band was finished with a solution (concentration 10 wt.% starch product) of the relevant sizing agent. The wet absorption was about 100%. The treated fabric was dried for 5 minutes at 100°C. Then the washing-out properties were determined as described before. The results are given in Table 2.

Table 2

Washing-out properties of carboxymethyl amylopectin potato starch of different DS

DS Washing-out properties

0.133 9 0.102 9 0.070 9

Example 3

A practical test was carried out on a Sucker Mύller sizing machine. Yarn: Polyester/cotton 65/35 Ne 30/1

43 x 22.5

Construction cloth = X 177.5

30 x 16

Sizing bath composition (in wt.%):

Carboxymethyl potato starch (DS 0.13! 8.4 % Polyvinyl alcohol (PVA 8-88) 5 % Antifoaming agent (Foamaster 340) 0.04% Antistatic agent ,(Kartax) 0.04% Wax (Olinor NW 81) 0.2 % When carboxymethyl potato starch (DS 0.13) is replaced by carboxymethyl amylopectin potato starch (DS 0.13), the weaving efficiency on a Picanol loom (600 rpm) is increased from 82% to 92%.

Example 4

A practical test was carried out on a Sucker Mϋller sizing machine .

Yarn: Cotton Ne 22/1

38.5 x 26.5

Construction cloth : X 171

22 x 22

Sizing bath composition (in wt.%)

Carboxymethyl potato starch (DS 0.13) 9.4 % Polyacrylate (Size CB; dry substance) 2.5 % Wax (Olinor NW 81) 0.2 %

When carboxymethyl potato starch (DS 0.13) is replaced by carboxymethyl amylopectin potato starch (DS 0.13), the weaving efficiency on a Sulzer loom (250 ppm) is increased from 94 to 97%.

Claims

1. Use of chemically modified amylopectin potato starch products as sizing agent for sizing natural and/or synthetic yarns .

2. Use according to claim 1, characterized by using the chemically modified amylopectin potato starch products in combination with other sizing agents, such as polyvinyl alcohol, carboxymethyl cellulose or polyacrylate.

3. A process for sizing natural and/or synthetic yarns, characterized by using chemically modified amylopectin potato starch products as sizing agent.